Temporal Changes in Mobility and Sexual Division of Labor in Holocene South
Australians: An Analysis of External Bone Metrics in the Roonka Flat Sample
by
Ethan C. Hill, BA in Anthropology
A Thesis
In
Physical Anthropology
Submitted to the Graduate Faculty
of Texas Tech University in
Partial Fulfillment of
the Requirements for
the Degree of
Master of Arts
Approved
Arthur C. Durband
Chair of Committee
Robert R. Paine
Ximena E. Bernal
Dominick Casadonte
Interim Dean of the Graduate School
May, 2014
Copyright 2014, Ethan C. Hill
Texas Tech University, Ethan C. Hill, May 2014
ACKNOWLEDGEMENTS
I would like to initially thank the First People of the River Murray who graciously
allowed me to study the Roonka Flat skeletal sample and Dr. Keryn Walshe for
facilitating examination of the remains at the Hindmarsh annex of the South Australian
Museum. Dr. Walshe’s hospitality and insistence to help in whatever way she could to
my research was deeply appreciated.
The completion of this thesis was is in large part to the patient and thoughtful
guidance of Dr. Arthur Durband. His attention to detail and knowledge of the larger
processes at play in Holocene Australia was an unrivaled resource in this endeavor. More
importantly, I need to thank Dr. Durband for his influence throughout my academic
career. His advisement has been an integral part of my growth as a student and
professional, but also as a person. For that, I am deeply and eternally grateful and I look
forward to a long and productive collaboration.
Further, I would be remiss to not mention the role that Dr. Robert Paine played in
the development of this thesis. Dr. Paine’s constructive critiques to my original proposal
and throughout the data collection and writing processes strengthened the final product.
No matter which part of the overall process I was in, he always had helpful advice to
contribute.
Dr. Ximena Bernal was also highly influential in the development of my thesis
project. My research paradigm that approaches studying prehistoric human samples in a
human behavioral ecology framework was developed after thought-provoking
discussions with Dr. Bernal. Her contribution to my research molded me into a more
complete student and for that I am thankful.
ii
Texas Tech University, Ethan C. Hill, May 2014
I would also like to thank my wife, Weslyn, whose constant encouragement was
vital to the success of this project. Her love and support helped me better appreciate the
larger picture of what I was trying to accomplish and helped me through all-to-frequent
stressful events. I would also like to thank Eleanor Adams who so kindly helped Dr.
Durband and me transfer the Roonka Flat remains to the Hindmarsh annex for convenient
study and Dr. Brian Cornish for his insightful contributions to my understanding of the
skeletal remains.
iii
Texas Tech University, Ethan C. Hill, May 2014
TABLE OF CONTENTS
ACKNOWLEDGEMENTS ............................................................................................. ii
ABSTRACT ...................................................................................................................... vi
LIST OF TABLES ......................................................................................................... viii
LIST OF FIGURES ......................................................................................................... iv
I. INTRODUCTION AND BACKGROUND ..................................................................1
Bone functional adaptation ...........................................................................................3
Optimal foraging theory ................................................................................................9
Holocene environment of South Australia .................................................................13
Archaeological models of Holocene behavior change ...............................................16
Archaeology of South Australia and the Murray River valley ................................20
Synthesis of archaeological models and OFT ............................................................23
Purpose of study ...........................................................................................................26
II. MATERIALS AND METHODS ...............................................................................28
Roonka Flat sample .....................................................................................................28
Methods .........................................................................................................................32
Analysis of mobility: the femur and tibia .................................................................32
Analysis of sexual division of labor: the humerus, ulna, and radius .....................35
Statistical methods.....................................................................................................37
III. RESULTS...................................................................................................................38
Lower limb diaphyseal shape index results ...............................................................38
Upper limb bilateral asymmetry results ....................................................................42
IV. DISCUSSION.............................................................................................................49
Mobility implications from lower limb circularity results .......................................49
iv
Texas Tech University, Ethan C. Hill, May 2014
Sexual division of labor implications from bilateral asymmetry results ...............50
Pre-ENSO behavior at Roonka Flat ...........................................................................52
Post ENSO behavior at Roonka Flat ..........................................................................54
IV. CONCLUSION ..........................................................................................................65
BIBLIOGRAPHY ............................................................................................................67
APPENDIX
A. EXTERNAL DIAPHYSEAL MEASUREMENTS ..................................................77
v
Texas Tech University, Ethan C. Hill, May 2014
ABSTRACT
The Roonka Flat skeletal sample is an important contribution to our
understanding of biological and behavioral adaptations in South Australians during the
Holocene. The development of the El Niño Southern Oscillation (ENSO) ~ 4 kya caused
significant changes in climate, vegetation, and faunal assemblages between the early
Holocene and the late Holocene. A transition from wetter and warmer conditions preENSO to cooler and dryer climate post-ENSO would have had an impact on human
populations inhabiting South Australia. In fact, archaeological deposits across the
continent denote a change toward a lighter, more flexible tool kit and a more diverse diet
at the onset of the post-ENSO period. Further, present archaeological evidence supports
predictions made by optimal foraging theory that South Australian Aboriginals became
more mobile and demonstrated more marked sexual division of labor after the onset of
ENSO.
The purpose of this study is to use the framework of bone functional adaptation to
test these predictions by examining changes in long bone diaphyseal metrics between preENSO and post-ENSO skeletons from the Roonka Flat sample. If people became more
mobile post-ENSO, then they should exhibit more ovular femoral and tibial diaphyses;
and if they had marked sexual division of labor, then males and females should
demonstrate differing patterns of upper limb bilateral asymmetry in the humerus, radius,
and ulna. Results from the femur, humerus, and ulna support these predictions. The
whole population becomes more mobile post-ENSO to better exploit less productive
patches by expanding their foraging radii. This change toward increased mobility is more
notable in females. Further, males and females demonstrate sexual division of labor with
vi
Texas Tech University, Ethan C. Hill, May 2014
males exhibiting a notable right-side bias reflecting the use of hunting implements such
as spears, while females have relative symmetry between the right and left sides perhaps
due to the increased use of technologies like grindstones and digging sticks used to gather
and process high handling-cost foods.
vii
Texas Tech University, Ethan C. Hill, May 2014
LIST OF TABLES
1.1
Testable predictions with supporting evidence from optimal foraging theory
and archaeological record ......................................................................................27
2.1
Roonka Flat sample by period and sex ..................................................................29
2.2
Bones examined by period, sex, and individual ....................................................30
2.3
Measurements taken on Roonka femora and tibiae ...............................................34
2.4
Measurements taken on Roonka humeri, ulnae, and radii .....................................36
3.1
Sex comparison of femoral midshaft external dimensions ....................................38
3.2
Temporal comparison of femoral midshaft external dimensions ..........................38
3.3
Sex comparison of tibial midshaft and nutrient foramen external dimensions ......40
3.4
Temporal comparison of tibial midshaft and nutrient foramen external
dimensions .............................................................................................................41
3.5
Sex comparison of humeral midshaft bilateral asymmetry results ........................43
3.6
Temporal comparison of humeral midshaft bilateral asymmetry results...............43
3.7
Sex comparison of ulnar bilateral asymmetry results ............................................45
3.8
Temporal comparison of ulnar bilateral asymmetry results ..................................45
3.9
Sex comparison of radial midshaft bilateral asymmetry results ............................47
3.10
Temporal comparison of radial midshaft bilateral asymmetry results...................47
viii
Texas Tech University, Ethan C. Hill, May 2014
LIST OF FIGURES
1.1
Map of southeastern Australia with an emphasis on the Murray River system.......2
1.2
Visual representation of external diaphyseal dimensions and corresponding cross
section ......................................................................................................................5
4.1
Depiction of typical tula use ..................................................................................61
ix
Texas Tech University, Ethan C. Hill, May 2014
CHAPTER I
INTRODUCTION AND BACKGROUND
Archaeologists have long debated the life ways of human populations in
prehistoric Australia (Bowdler, 1981; Lourandos, 1983, 1997; Flood, 2001; Hiscock,
2002, 2006). While archaeological evidence is vital for understanding human behavior,
human prehistory in Australia cannot be understood without also framing it within an
ecological context. This continent experienced a shift from optimal climatic conditions
for humans in the early Holocene to a markedly deteriorated environment later in the
epoch. Environmental instability was particularly noted in South Australia (Kershaw,
1995). The new environmental stressors introduced by climatic instability and reduced
precipitation had a salient influence on the behavior of prehistoric South Australian
Aboriginals
In fact, the archaeological record of South Australia exhibits distinct changes in
tool kit and faunal assemblages in the late Holocene corresponding to dryer conditions
(Lourandos, 1983, 1997; Mulvaney and Kamminga, 1999; Flood, 2001; Hiscock, 2002,
2006). While models that explain these alterations are quite detailed in their description
of Aboriginal society, they can be reduced to what they claim about human mobility and
sexual division of labor (Hiscock, 2002, 2006; Lourandos, 1983, 1997). These two
aspects of human behavior are intimately linked to foraging decisions and are thus
significantly influenced by environmental conditions (Bird and O’Connell, 2006).
Therefore synthesizing foraging and archaeological evidence will form a more complete
model concerning mobility and sexual division of labor in Holocene South Australia.
1
Texas Tech University, Ethan C. Hill, May 2014
The Roonka Flat cemetery site from South Australia provides an ideal opportunity
to test predictions made from synthesized archeological and foraging models (Pretty,
1977, 1986, 1988; Prokopec, 1979). Burials from this site date to phases throughout the
Holocene, thus facilitating comparisons between early and late Holocene samples
representative of an ameliorated and harsh climate respectively. Since human skeletons
are affected by repetitive and strenuous activities, the examination of external long bone
metrics can be used to determine whether environmental conditions did indeed influence
South Australian Aboriginal behavior during the Holocene.
Fig. 1.1. Map of southeastern Australia with an emphasis on the Murray River system (modified from
Pretty, 1986)
2
Texas Tech University, Ethan C. Hill, May 2014
Bone functional adaptation
This study has several concepts that need to be further explained before they are
applied to the query at hand. An analysis of human behavior should be multifaceted cite.
Humans are subject to environmental forces, but are also able to culturally and
technologically adapt to their ecological setting. Consulting ecological and archaeological
models will form testable predictions of behavioral change that will then by examined
through the concept of bone functional adaptation. While bone shape is largely
determined at the genetic level, it is also a plastic tissue that is subject to remodeling
(Frost, 1987,1988; Ruff, 2000; Lovejoy et al., 2003; Ruff et al., 2006). Methodologies
that examine the shape and density of human cortical bone are important tools for
understanding behavior of both recent and prehistoric humans (Lovejoy et al., 1976;
2003; Lovejoy and Trinkaus 1980; Ruff and Hayes, 1983a,b; Ruff et al., 1984; Trinkaus
et al., 1994; Trinkaus and Ruff, 1999a, b; Stock and Pfeiffer, 2001, 2004).
Throughout an individual’s life, bone is constantly being deposited to areas under
physical stress and resorbed in locations of the bone where extra buttressing is not needed
to resist compressional, bending, or torsional strains (Ruff et al., 2006). Bone functional
adaptation suggests that bone shape, especially throughout long bone diaphyses, can
serve as a record of an individual’s lifetime behavior (Ruff, 2000; Ruff et al., 2006).
Frequency and duration of strenuous activities produce lasting changes in internal and
external bone structure (Ruff and Hayes, 1983a,b). Since long bones remodel in response
to physical activity, many studies have used bone functional adaptation to examine
foraging, food processing, and mobility behavior in skeletal samples (Ruff, 2000; Stock
and Pfeiffer 2001, 2004; Ruff et al., 2006).
3
Texas Tech University, Ethan C. Hill, May 2014
Many of these studies have examined the internal structure of long bone shape
through cross-sectional geometry (Ruff and Hayes, 1983a,b; Ruff, 2000; Stock and
Pfeiffer, 2001, 2004; Holt, 2003; Ruff et al., 2006; Marchi 2008). Long bone cross
sections can be prepared in several ways, but the goal is to acquire a measurable
representation of a perpendicular slice through the diaphysis (Ruff, 2000; Ruff et al.,
2006). The most common cross-sectional properties that are measured are cortical area
(CA), second moments of area (I), and polar second moments of area (J) (Ruff, 2000;
Ruff et al., 2006). These variables help to measure diaphyseal resistance to
compressional, bending, and torsional strains respectively (Ruff, 2000; Ruff et al., 2006).
The cross-sectional properties that are germane to this study are second moments of area.
Second moments of inertia quantify bone deposition within a particular axis of interest
(e.g. maximum/minimum, anterior/posterior, etc.). Axes with greater bone deposition are
assumed to reflect increased tolerance to physical strains.
While cross-sectional geometry can be highly informative, methods of data
collection complicate the process. Earlier research was highly invasive and relied on
having photographs of physically exposed cross sections (Ruff, 2000). Either previously
broken bones could be used or the bone would have to be manually sectioned with a saw
(Ruff, 2000). This approach could possibly be justified if only several skeletons were
being examined, but for a larger study like the present one, the destructive costs far
outweigh any academic gain. More recent studies use non-invasive computed
tomography (CT) scanning to obtain digital cross sections (Ruff, 2000; Ruff et al., 2006;
Shaw and Stock, 2011). While this is definitely preferable to physical methods from a
preservation perspective, it can be a costly endeavor to scan a large number of skeletons
4
Texas Tech University, Ethan C. Hill, May 2014
(Ruff et al., 2006). Further, gaining permission from local indigenous groups can be a
long and arduous process.
While studies that examine the internal structure of long bones through crosssectional geometry are preferable, other research has been successful at extrapolating the
theoretical background of bone functional adaptation to external bone anatomy (e.g.
circumference and diameter) (Ruff, 1987; Bridges, 1989; Bridges et al., 2000; Pearson,
2000; Wescott, 2001, 2006; Stock and Shaw, 2007; Weiss, 2009). External bone
dimensions cannot give information regarding cortical bone density or thickness, but they
reflect internal cross-sectional geometrical properties (Ruff, 1987; Bridges et al., 2000;
Wescott, 2006). Numerous studies have supported the validity of using diameters and
circumferences as proxies for overall bending rigidity and strength in long bone
diaphyses (Fig. 1.2) (Bridges, 1989; Pearson, 2000; Wescott, 2001, 2006; Weiss, 2009).
Also, several analyses that examined the same sample through both methods found
complimentary results (Larsen, 1981; Ruff et al., 1984; Cole, 1994; Ruff, 1994).
Fig. 1.2. Visual representation of external diaphyseal dimensions and corresponding cross section (from
Stock and Shaw, 2007)
5
Texas Tech University, Ethan C. Hill, May 2014
Additionally, experimental studies have corroborated the use of external long
bone properties as proxies for cross-sectional dimensions (see Wescott, 2006 for
extended discussion). Pearson (2000) compared cross-sectional J properties to estimated
torsional rigidity from external dimensions and found a correlation of 0.898. Wescott
(2001) also backed this assertion with a correlation of 0.829. Other analyses have
specifically analyzed the relationship between cross-sectional diaphyseal shape to
external measurements in the femora of over 500 individuals (Rockhold, 1998; Wescott,
2001). These studies found that external measurements can explain 70-98% of the
variation seen in cross-sectional geometrical analyses of the femur (Rockhold, 1998;
Wescott, 2001). External measurements are not as accurate as cross-sectional geometry
and tend to show more overlap between samples (Ruff, 2002), but when sample
differences are observed they reflect significant results that would be supported by crosssectional research (Rockhold, 1998; Pearson, 2000; Wescott, 2001, 2006).
However, this is not to claim that external measurements of bone strength can be
directly compared to cross-sectional data (Pearson, 2000; Ruff, 2002; Wescott, 2006).
They are two distinct data sets that reveal similar types of information about human
behavior. Both are valuable avenues of inquiry that can complement each other (Pearson,
2000; Wescott, 2006; Ruff, personal communication). External dimensions may not
reveal internal structure like cross-sectional analyses, but they are sufficient for observing
overall bone robusticity and diaphyseal shape (Bridges, 1989; Bridges et al., 2000;
Pearson, 2000; Wescott, 2006). Thus, external bone metrics can be used to examine how
human behavioral patterns differ between skeletal samples by looking at bilateral
6
Texas Tech University, Ethan C. Hill, May 2014
differentiation in limb usage and differences in long bone diaphyseal shape (Bridges,
1989; Bridges et al., 2000).
It has been well established that bones of the lower limb become more ovular as
human populations become more mobile (Ruff and Hayes, 1983a, b; Stock and Pfeiffer,
2001, 2004; Holt, 2003; Marchi, 2008). Physical activity of the lower body associated
with bipedal locomotion causes more strains to be placed in the anteroposterior (AP)
plane of the bone from the adducting and abducting muscles of the knee joint (Ruff et al.,
2006). These strains cause more bone deposition in the AP plane while bone in the
mediolateral (ML) plane remains unaffected or loses mass (Ruff et al., 2006). A highly
informative index of overall mobility is the ratio between these two values, which
provides a measure of diaphyseal shape in femora and tibiae (Sparacello and Marchi,
2008). In the lower limb, diaphyseal shape is more closely linked to overall mobility than
overall robusticity, which tends to be more influenced by the topography of the
environment (Holt, 2003; Sparacello and Marchi, 2008). Since the present study is
conducted with samples that reside in the same geographical location, diaphyseal shape is
more revealing than overall robusticity. A higher value represents more bone in the AP
plane relative to the ML plane of the diaphysis.
Many authors have noted that diaphyseal shape of the femur is the most reliable
indicator of human mobility (Ruff, 2000; Holt, 2003; Ruff et al., 2006; Stock, 2006;
Marchi, 2008; Sparacello and Marchi, 2008), thus this study anticipates more significant
results from this bone. However, the tibia will also be examined in this analysis and may
yield additional insights. Moreover, shape differences between samples in the tibia may
be especially significant since the tibia is more resistant to locomotive induced
7
Texas Tech University, Ethan C. Hill, May 2014
remodeling (Stock, 2006). Distal limb segments are more conservative in the addition of
new bone tissue as a means to maintain energetic efficiency (Lieberman and Pearson,
2001; Marsh et al., 2004; Stock, 2006). Thus, a unit of bone tissue added to the tibia is
more costly than the same amount added to the femur (Lieberman and Pearson, 2001;
Marsh et al., 2004). Like cross-sectional geometrical properties, external dimensions
become more ovular – have higher diaphyseal shape indexes – in the femora and tibiae of
individuals who are more mobile (Bridges, 1989; Bridges et al., 2000; Wescott, 2001,
2006; Lovejoy et al., 2003).
External diaphyseal dimensions of the upper limbs can also serve as a valuable
source of information concerning human behavior in archaeological samples. Various
studies have examined upper limb bilateral asymmetry to make inferences about
subsistence-related behaviors and sexual division of labor in skeletal samples (Bridges,
1989, 1995; Fresia et al., 1990; Bridges et al., 2000; Wescott and Cunningham, 2006;
Maggiano et al., 2008; Sládek et al., 2007; Weiss, 2009). Differences in robusticity
between the right and left sides are often reflective of the types of activities being
performed (Weiss, 2009). Asymmetry usually indicates more right-side dominance, while
more symmetric values reflect roughly equal involvement of the right and left sides
(Weiss, 2009).
Experimental evidence from modern athletes corroborates these assertions
(Haapasalo et al., 2000; Kontualainen et al., 2002; Nikander et al., 2006; Shaw and Stock,
2009). The swinging motion used by tennis (Haapasalo et al., 2000) and racquetball
players (Kontualainen et al., 2003), as well as the throwing motion of cricket bowlers
(Shaw and Stock, 2009) was shown to produce significantly higher levels of upper limb
8
Texas Tech University, Ethan C. Hill, May 2014
bilateral asymmetry than control groups. These results remained consistent even when
compared to other athletes such as volleyball players, soccer players, and weightlifters
who exhibited relative symmetry of the upper limbs (Nikander et al., 2006).
In foraging populations, upper limb asymmetry is most often associated with
hunting activities (Bridges, 1989; Fresia et al., 1990; Trinkaus et al., 1994; Bridges et al.,
2000; Weiss, 2009). Hunting overwhelmingly relies on the use of one-handed weapons
that are thrown, thrust, or swung (e.g. spears, clubs, blades, etc.) (Trinkaus et al., 1994;
Bridges et al., 2000). Additionally, research has also linked the use of one-handed multiutility tools such as stone axes to high bilateral asymmetry (Sparacello and Marchi,
2008). Inversely, symmetry of the upper limbs is normally associated with food
processing technologies such as grindstones, mortars and pestles, and millstones
(Bridges, 1989; Bridges et al., 2000; Sparacello and Marchi, 2008; Weiss, 2009). While
food processing is normally associated with agriculture, any foraging group that
incorporates high handling cost foods into their diet will use these technologies (Bridges
et al., 2000). By measuring asymmetry in the upper limbs it is possible to make
inferences about sexual division of labor. If men and women are performing similar
activities they will have similar levels of asymmetry, but if a stark division of labor is
present men will likely be more asymmetric than women.
Optimal Foraging Theory
While mobility and sexual differentiation of behavior will be measured in this
study using a bone functional adaptation framework, consulting optimal foraging theory
can help form predictions about behavior change within the context of a particular
9
Texas Tech University, Ethan C. Hill, May 2014
ecosystem. Since the environment of South Australia alters dramatically from the early to
late Holocene, foraging models can prove useful in forming testable assumptions about
the behavior of prehistoric Australian Aboriginals. Optimal foraging theory (OFT) is a
family of models that posit that animals will maximize caloric returns in relation to
energetic costs to raise individual fitness (MacArthur and Pianka, 1966; Sih and
Christensen, 2001; Stephens et al., 2007). This study will utilize three OFT models in
particular: encounter-contingent prey choice (MacArthur and Pianka, 1966), patch choice
(Stephens et al., 2007; O’Connell and Allen, 2012), and marginal value theorem
(Charnov, 1976).
The “encounter-contingent prey choice model” (PCM), sometimes referred to as
“diet breadth” or “optimal diet”, attempts to explain foraging behavior through search
and handling costs (MacArthur and Pianka, 1966). Search describes all activities prior to
prey encounter, and handling is defined as the energetic costs related with pursuit,
capture, collection, and processing of prey items after initial encounter (MacArthur and
Pianka, 1966). PCM predicts that foragers prefer food items that maximize net caloric
gain by having relatively low handling costs in relation to caloric benefit (MacArthur and
Pianka, 1966). High-ranking items are consumed first and lower-ranked items are
pursued in descending order based on net caloric gain (MacArthur and Pianka, 1966).
According to PCM, post-encounter profitability is more important in foraging decisions
than the overall abundance of a food item (MacArthur and Pianka, 1966; Bird and
O’Connell, 2006).
Moreover, food items are not distributed evenly throughout an environment, but
occur clumped randomly both geographically and temporally in patches (Stephens et al.,
10
Texas Tech University, Ethan C. Hill, May 2014
2007). Patch choice predicts that humans will choose to exploit patches that offer highranking food items before lower ranked patches (Bird and O’Connell, 2006; Stephens et
al., 2007). “Sweet spots” are patches in the environment that are able to support more
high-ranking prey and should be exploited first by foragers (O’Connell and Allen, 2012).
However, if travelling costs for a higher-ranking patch are too high, a lower-ranking
patch that is closer may be energetically more beneficial to exploit (Bird and O’Connell,
2006).
Marginal value theorem (MVT) further expands upon the patch choice concept of
resource distribution and quality by incorporating travel costs into the model (Charnov,
1976). Since patches have finite resources, there is a diminishing return of resource
intake compared to the costs associated with travel and foraging time (Charnov, 1976).
Foraging decisions concerning whether to continue exploiting a patch or to move to
another should maximize overall net caloric intake and a forager should relocate when
the “capture rate in the patch drops to the average capture rate for the habitat” (Charnov,
1976: 132; Stephens et al., 2007). MVT predicts that animals will forage longer in a patch
if cost of movement to another patch is high or if average patch quality in the
environment is low (Charnov, 1976; Stephens et al., 2007).
MVT indicates that humans will stay longer in patches in a poor habitat (Charnov,
1976), but they greatly expand their foraging range within habitats as overall quality
declines in order to access rarer high-ranked patches (Codding and Bliege Bird, 2012).
Further, as high-ranking food items become depleted, humans will be forced to relocate
to another patch in accordance with PCM (Codding and Bliege Bird, 2012). This suggests
that humans will display more mobility in environments with poor patch quality and
11
Texas Tech University, Ethan C. Hill, May 2014
distribution in order to pursue high-ranking resources (Bird et al., 2009; Codding and
Bliege Bird, 2012). Not only do people have to move more frequently due to a paucity of
preferable food items, but they must also expand their foraging radii to incorporate
additional patches (Bird et al., 2009; Codding and Bliege Bird, 2012; O’Connell and
Allen, 2012).
While one should be wary of applying behavioral ecology models
deterministically to human populations due to the dynamic entity of culture, human
populations show some common patterns concerning the sexual division of labor. The
vast majority of foraging populations follow a pattern of males hunting larger terrestrial
or aquatic animals while females gather reliable, but low yielding, food items such as
plant foods, opportunistic capturing of small game, and shellfish (Hawkes et al., 1991,
1997; Stiner et al., 2000; Waguespack, 2005). Waguespack (2005) notes that sexual
division of labor does not diminish the contribution of either sex. Rather the
complimentary foraging goals of each sex tend to simply be the result of differing
reproductive goals (Waguespack, 2005). The continued role of mothers provisioning their
offspring after weaning is a uniquely human adaptation (Hawkes et al., 1991, 1997).
Other apes share food with unweaned infants, but human mothers give more, do so more
frequently, and give food to their immature children in a state that is more easily
digestible (Hawkes et al., 1997).
Further, the breadth of a diet set can indicate the degree of sexual division of labor
(Bird, 1999; Bird et al., 2009). Bird et al. (2009) note that more broadly based economies
normally show more differentiation between the sexes as males focus on unpredictable
prey items with a high caloric return and women collect reliable, low calorie foods. This
12
Texas Tech University, Ethan C. Hill, May 2014
is further dictated by the amount of hunted game that is present in the diet (Waguespack,
2005). When hunting of larger game – often done by adult males – becomes less
productive, women tend to introduce more gathered foods (Waguespack, 2005). Thus, as
meat contribution diminishes, the diet set broadens to include lower ranking, high
handling cost, plant products like nuts and seeds (Waguespack, 2005). Furthermore, this
trend remains consistent even when one includes aquatic meat sources along with hunted
game (Waguespack, 2005). While behavior is not determined by environment, optimal
foraging theory provides reliable models that can serve as a baseline for how humans are
expected to interact with their environment (Hawkes et al., 1991, 1997; Stiner et al.,
2000; Waguespack, 2005; Bird et al., 2009).
Holocene environment of South Australia
The environment of Holocene Australia is characterized by large climatic shifts.
The beginning of the Holocene is marked by a warming of the climate as Australia comes
out of the last glacial period (Hiscock, 2002; Gagan et al., 2003). However, the early
Holocene and late Holocene differ markedly in the amount of effective precipitation in
the environment (Hiscock, 2002; Gagan et al., 2003). This is primarily due to the effects
of the El Niño Southern Oscillation (ENSO) (Shulmeister and Lees, 1995; Gagan et al.,
2003). ENSO is a complex interaction between ocean surface temperatures in the tropical
eastern Pacific and air surface pressure in the tropical western Pacific (see Gagan et al.,
2003 for complete review). El Niño warm phases and La Niña cool phases fluctuate
every 2-7 years and produce drought conditions or wet periods respectively in Australasia
13
Texas Tech University, Ethan C. Hill, May 2014
(Gagan et al., 2003). However, of special importance for Australian climate, drought
periods tend to be longer and more severe than alternate wet periods (Gagan et al., 2003).
ENSO was relatively weak throughout the early Holocene, but began to
strengthen around 5 kya (Gagan et al., 2003). However, ENSO-induced climate change
occurred at different rates across the continent. South Australia did not did not see the full
effects of this cooling and drying event until ~4 kya (Gagan et al., 2003). To reflect the
significant environmental differences before and after the establishment of ENSO, the
present study will recognize the early Holocene as 10 kya – 4 kya and the late Holocene
as 4 kya – present. Thusly, analysis of the Roonka Flat sample will adhere to these time
periods by referring to the early and later Holocene sample as pre-ENSO and post-ENSO
respectively. Although this is an arbitrary divide, this analysis is examining
environmental-induced behavioral changes. Therefore this divide better reflects the two
predominating climates of the Holocene in South Australia and the human populations
that lived during each period.
A weakened ENSO produced a relatively stable Australian climate throughout the
early Holocene (Shulmeister and Lees, 1995; Gagan et al., 2003). Conditions were wetter
and warmer than the present, even in the arid interior of the continent (Singh and Luly,
1991; Shulmeister and Lees, 1995). The average temperature of southern and southeast
Australia was ~1°C warmer and precipitation was 30% higher than today with most
moisture arriving in the winter months typical of a Mediterranean climate (Kershaw,
1995). This seemingly minor change led to frequent flooding of lake and river systems as
more surface water was available due to increased effective precipitation (Shulmeister
14
Texas Tech University, Ethan C. Hill, May 2014
and Lees, 1995; Gagan et al., 2003). Also, rising sea levels produced productive estuary
and tidal flat habitats near the coast (Woodroffe, 2000).
Woodlands became more prevalent throughout southeastern South Australia,
especially the Murray River basin, during this climatic optimum with Eucalyptus trees
being the dominant genera (Markgraf et al., 1992; Kershaw, 1995). Nothofagus and
Pomaderris, temperate forest staples, crept into the wetter portions of southeast South
Australia (Kershaw, 1995). Even presently arid portions of South Australia had dense
coverings of grass and mallee eucalypt shrubs with intermittent open woodlands
comprised of Casuarina and Callitris (Pretty, 1986; Kershaw, 1995).
The late Holocene is characterized by increasing aridity and greater climatic
fluctuations as ENSO begins to resemble its modern form with greater cycle variation
(Shulmeister and Lees, 1995; Hiscock, 2002; Gagan et al., 2003). ENSO produced more
frequent and severe droughts in southern and southeast Australia (Markgraf et al., 1992;
Kershaw, 1995). This ENSO-dominated climate was in full effect by 4 kya and has
persisted to today (Kershaw, 1995). Present average annual precipitation for southeast
South Australia ranges from ~200mm in the arid interior to ~500mm near the coast
(Australian Government: Bureau of Meteorology). However, these averages are
significantly lower during El Niño drought events (Gagan et al., 2003). Mean annual
temperature ranges from 12 – 18°C with summer highs often reaching the low-30s° and
winter lows ~5° (Australian Government: Bureau of Meteorology).
Although precipitation and temperature averages of the late Holocene were not
drastically different than the early Holocene, ENSO-produced instability has had a
profound effect on the environment (Tudhope et al., 2001). A reduction in effective
15
Texas Tech University, Ethan C. Hill, May 2014
precipitation caused lower lake levels and slower flowing rivers across most of the
continent (Kershaw, 1995). Eucalyptus woodlands were reduced to stream and lake
systems as a result (Markgraf et al., 1992). The Murray River valley also contained reedfilled lagoons along most of its length (Pretty and Kricun, 1989). Inland areas became
dominated by low, bushy shrubs and grasses belonging to Chenopodiaceae, Tubuliflorae,
and Poaceae families (Singh and Luly, 1991). Limestone dolines were also common on
the plains above river basins (Pretty and Kricun, 1989). The arid interior became more
pronounced with a major reduction in ground cover (Kershaw, 1995). This contributed to
the activation of dune activity and more recurrent and intense burning along with
increased human disturbance (Kershaw, 1995).
Archaeological models of Holocene behavior change
Notable changes in archaeological assemblages ~4 kya also correspond to these
notable climatic alterations in Australia. Archaeologists have proposed three primary
models to explain the changes that occur throughout the Australian Holocene: diffusion,
intensification, and risk minimization. The diffusion model proposes that Holocene
technologies originated in Southeast Asia and were spread to the Australian mainland by
migrating human groups via the Indonesian archipelago (Bowdler, 1981; Hiscock, 2002,
2006). Although the appearance of the dingo 4 – 5 kya suggests that human migrations
from Asia were occurring during the mid-Holocene, the majority of evidence indicates
that the Australian toolkit arose as a domestic product (Lourandos, 1997; Hiscock and
Attenbrow, 1998; Hiscock, 2002, 2006). Further, the diffusion model does not make
16
Texas Tech University, Ethan C. Hill, May 2014
predictions about human mobility or sexual division of labor, thus more attention will be
given to intensification and risk minimization models.
The broad patterns exhibited by intensification are related to an overall trending
from simpler to more complex economic and cultural systems from the late Pleistocene
throughout the Holocene (Lourandos, 1983, 1985, 1997). Lourandos (1983, 1985, 1997)
proposes that an increase in population density during the late Holocene, especially near
water sources, caused previously splintered foraging groups to band together to form
alliances through kin, marriage, and trading relationships (Lourandos, 1983, 1985, 1997).
These alliances sought to control economic resources and food sources that were rich in
biomass (Lourandos, 1983, 1985, 1997). Hughes and Lampert (1982) suggest that greater
site density as well as richer archaeological deposits in the late Holocene support an
increase in population density. Pardoe (1988) has also proposed that a greater density of
late Holocene burials at cemetery sites such as Roonka is evidence for population growth
in the Murray River corridor. This research has been expanded upon by various
researchers who insist that population growth that began in the mid-Holocene is a
phenomenon that occurred almost simultaneously in various regions across Australia
(Flood, 2001; David, 2002; Turney and Hobbs, 2006).
Lourandos (1983, 1985, 1997) further argues that the intensification of resource
exploitation led to greater surpluses and less fluctuation in food availability, which
spurred further population growth. Researchers who support intensification argue that
historically recorded aspects of Aboriginal society are remnants of continent-wide food
procurement strategy alterations that occurred in the mid-Holocene (Flood, 1980, 2001;
Bowdler, 1981; Lourandos, 1983, 1997). Eeling and fishing in the southeastern wetlands
17
Texas Tech University, Ethan C. Hill, May 2014
(Lourandos, 1983), exploitation of cycad seeds in the eastern highlands (Bowdler, 1981),
and moth collecting in the southeast (Flood, 1980, 2001), have all been proposed as
ethnographically recorded activities that support resource intensification in several
Australian regions.
The intensification model proposes that human groups became more sedentary in
the post-ENSO period to fully exploit preferred resources (Lourandos, 1983, 1985, 1997).
Side effects of this process are the development of social hierarchies and territoriality
(Lourandos, 1983, 1985, 1997). Lourandos (1997) posits that during the late Holocene
social systems became “closed” with more intergroup ideological differences present than
during earlier periods. Territorially would have arisen from the combined effects of social
and environmental stressors (David and Chant, 1995). David and Lourandos (1998)
suggest that the proliferation and regional diversification of rock art styles during the late
Holocene functioned to signify territories as well as the human groups that controlled
them. Further, they suggest that the presence of cemeteries, such as Roonka, is a side
effect of sedentary lifestyles (David and Lourandos, 1998).
Hiscock (1994, 2002, 2006; Hiscock and Attenbrow, 1998, 2004) rejects
Lourandos’ hypotheses that there was a late Holocene population explosion or that
humans became sedentary. Hiscock (1994, 2002, 2006) instead argues that human
behavior in prehistoric Australia should be modeled as a risk minimization strategy. He
suggests that Holocene toolkits based on backed artifacts – flaked-stone tools that were
relatively general, flexible, and easy to create – became more prevalent as a consequence
of environmental degradation in the late Holocene (Hiscock, 2002, 2006, 2008).
Although backed artifacts are present in Australia by 15 kya (Hiscock and Attenbrow,
18
Texas Tech University, Ethan C. Hill, May 2014
1998, 2004), they proliferated dramatically beginning ~4 kya (Hiscock, 2002). By having
a flexible toolkit, a wide range of habitats could be exploited without significant
economic cost since new toolkits would not have to be created (Hiscock, 1994).
Compound tools with backed artifacts, although relatively simple to construct, could be
used for multiple tasks (Hiscock, 1994, 2002, 2006). Microscopic studies have
demonstrated that backed artifacts were used for hunting and food gathering as well as
working wood, bone, and animal pelts (Slack et al., 2004; Robertson, 2005; Hiscock,
2006).
Instead of alliance formation, Hiscock (2002, 2004, 2008) posits that humans
lived in small foraging groups that became more mobile in response to environmental
uncertainty. Additionally, the evidence that Lourandos (1983, 1997) cites that suggests a
population explosion is nothing more than preservation bias to artifacts deposited more
recently in time (Attenbrow, 2004). Attenbrow (2004) also points out that the preference
of archaeologists to excavate rock shelters with visible artifacts can skew results toward
more recent human occupation.
While there is some genetic evidence for rapid population growth soon after
colonization of the continent during the Pleistocene (Ingman and Gyllensten, 2003), these
studies are primarily limited to mtDNA. The relatively slow mutation rates of mtDNA
have prevented meaningful research on Holocene population growth (Kayser et al.,
2001). Further, Littleton and Allen (2007) posit that cemeteries in the Murray River
corridor are not the result of sedentary populations, but “echoes of the past”. Cemeteries
were used primarily by foraging groups that came upon earlier clusters of burials, which
19
Texas Tech University, Ethan C. Hill, May 2014
were simply interpreted as good places to bury a body, rather than owned territories
(Littleton and Allen, 2007).
Archaeology of South Australia and the Murray River valley.
While risk minimization and intensification pertain to continent-wide
archaeological changes in the Holocene, it is also important to understand the regional
record of South Australia and sites along the Murray River. The technology of early
Holocene South Australia is characterized by flaked-stone scrapers, points, and blades
(Pretty, 1986; Hiscock, 2002, 2006). There is also evidence at Roonka Flat that ground
stone axes were manufactured (Pretty, 1977). Tools and weapons made of organic
materials are scarce in the archaeological record of the early Holocene, but several
wooden implements have been uncovered at the site of Wyrie Swamp in southeast South
Australia (Pretty, 1986; Hiscock, 1994, 2006; Flood, 2001). This site has yielded short
spears, wooden barbed spears, and digging sticks (Pretty, 1986; Hiscock, 1994, 2006;
Flood, 2001). It is possible that the short spears found at this site would have been used
with a woomera, or spear thrower (Mulvaney and Kamminga, 1999; Flood, 2001).
Additionally, several boomerangs were found at Wyrie Swamp, some of which have the
requisite features of a returning boomerang (Hiscock, 1994, 2006; Flood, 2001).
The late Holocene in South Australia is characterized by a more extensive
archaeological record and the proliferation of backed artifacts throughout most of the
continent beginning ~4 kya (Pretty, 1986; Hiscock, 1994, 2002, 2006). Tulas (flake-stone
chisels) also become more common and are probably part of the larger backed artifact
toolkit (Veth et al., 2011). Flaked-stone points, former staples in the Australian
20
Texas Tech University, Ethan C. Hill, May 2014
archaeological record, begin to decline in visibility while bone implements (pins,
projectile points, awls, etc.) become more common across the region (Pretty, 1986; Pate,
2006). Kangaroo fibulae that have been sharpened into awls are frequently uncovered in
burial goods (Pate, 2006). Particular food processing technologies seem to also increase
in density. Seed grinders and millstones begin to diversify and become more common
across South Australia (Pretty, 1986), and earth ovens are found in Roonka Flat dunes
(Pretty, 1977).
Early Holocene dietary evidence is sparse in the Roonka archaeological record, as
well as in South Australia as a whole (Pretty, 1977; Pretty, 1986). In fact, faunal evidence
for early Holocene Roonka consists almost entirely of assorted kangaroo and wallaby
(Macropus sp.) and freshwater shellfish remains (Pretty, 1977). The faunal remains at
Devon Downs, a rockshelter South of Roonka along the Murray River, provide the
richest record of early Holocene diet (Smith, 1978, 1982). Deposits from 5 kya contain
butchered remains of predominantly large and medium-sized game: western grey
kangaroo (Macropus fuliginosus), small wallaby (Macropus sp.), brush-tailed possum
(Trichosurus vulpecula), emu (Dromaius novaehollandiae), and Australian crane (Grus
rubicundus) (Smith, 1982). While no shellfish remains are present, Maccullochella peeli
(Murray cod) and Emydura macquarii (river tortoise) represent a small percentage of
fauna from this period (Smith, 1982).
Inversely, late Holocene deposits show a wider range of food remains. Roonka,
Devon Downs, and the Lower Murray site of Swanport show that riverine and terrestrial
animals were exploited. While the above species are still being hunted, there is a notable
shift toward smaller game in the late Holocene with the incorporation of bandicoot
21
Texas Tech University, Ethan C. Hill, May 2014
(Parameles sp.), Tasmanian devil (Sarcophilus harrisii), rat (Rattus sp.), and various
lizard and snake genera (Amphibolurus, Tiliqua, Trachydosaurus, and Chelodina) (Pretty,
1977; Smith, 1982; Pate, 2006). Additionally, freshwater fish, shellfish, and mussels
dominate faunal assemblages at these sites with a wide variety of species being harvested
(Pretty, 1977; Smith, 1982; Pate, 2006). Smith (1978, 1982) has further proposed that late
Holocene sites like Devon Downs are evidence of seasonal foraging behavior, with
summer exploitation of Murray River foods and winter terrestrial hunting and gathering.
Floral remains do not preserve as readily, but it is likely that plants that yielded fleshy
fruits, nuts, roots, and berries were also commonly gathered (Pate, 2006).
Late Holocene dietary habits have also been informed by stable carbon and
nitrogen isotope analyses on human bone collagen from Roonka Flat skeletons (Pate,
1998a,b, 2000, 2006). Unfortunately, bone collagen does not preserve readily and thus
early Holocene skeletons could not be sampled (Pate, 1998a,b, 2000). These studies
support the above archaeological evidence from the Murray River valley by indicating
that dietary protein was gained from multiple sources. Most dietary protein was obtained
from local terrestrial herbivores (40-50%), but freshwater fish and shellfish also made up
a large proportion (30-40%) of the Roonka diet (Pate, 1998a,b, 2000). Terrestrial
carnivores comprised the remaining 10-15% of dietary protein (Pate, 1998a,b, 2000).
Furthermore, adult males have carbon isotope values that are somewhat more positive
than adult females, indicating a diet that included more terrestrial protein (Pate, 1998,
2000). Adult females and subadults have similar carbon and nitrogen isotope values,
potentially as the result of a diet that included more terrestrial and aquatic plants and
freshwater shellfish (Pate, 1998, 2000). These data indicate that there was some
22
Texas Tech University, Ethan C. Hill, May 2014
inequality in food sharing practices between the sexes (Pate, 2000); however, this is
common in hunter-gatherer populations (Waguespack, 2005).
Synthesis of archaeological models and OFT
It is tempting to examine mobility and sexual division of labor as codependent
variables, similarly to the archeological models presented. However, this study will
consider them separately. It is not the intent of this study to bolster risk minimization or
intensification as complete models, but rather to test what the combined OFT and
archaeological evidence predicts for mobility and sexual division of labor using
osteological metrics. Thus, the Roonka population does not have to be mobile with little
sexual differentiation or sedentary with notable sexual differentiation. Any mixture of
these attributes may be displayed within a foraging population.
The Holocene environment of Australia provides an ideal opportunity to apply
foraging models to a prehistoric Australian Aboriginal skeletal sample. The warmer and
wetter climatic optimum of the early Holocene provided a greater abundance of higherranking patches (i.e. open woodlands, estuaries, etc.) that were more evenly spread
throughout the environment. High-ranking food items with low handling costs were also
more prevalent. The Murray River valley and adjacent shrub and grasslands and
woodlands would have provided a greater quantity of preferable game animals like
kangaroos, wallabies, and emus that provide optimal caloric return in relation to handling
costs (Smith, 1982; Pretty, 1988). Thus, Aboriginals would not have needed to forage
over large distances to incorporate sufficient calories into their diet.
23
Texas Tech University, Ethan C. Hill, May 2014
The cooling and drying of the late Holocene after ENSO establishment led to an
overall decline in patch quality as high-ranking items became scarcer (Shulmeister and
Lees, 1995). Rich patches that were relegated to large water sources were separated by
large expanses of low-ranking grasslands and shrublands (Pretty, 1986; Shulmeister and
Lees, 1995). Further, the expansion of the arid zone would have reduced the overall area
of exploitable habitats (Kershaw, 1995; Shulmeister and Lees, 1995). Although
grasslands are able to support some high-ranking prey items, they would have been lower
in number and variety than in early Holocene woodland environments (Pretty, 1986;
Shulmeister and Lees, 1995; Kershaw, 1995). This change in patch distribution and
quality could have had a salient effect on human behavior as high-ranking food items and
overall patch quality declined in the late Holocene. Patches would have been exhausted
more quickly and spread farther apart than in the early Holocene, causing populations
living in the Murray River valley to travel frequently and over longer distances (Bird et
al., 2009; O’Connell and Allen, 2012)
The intensification and risk-minimization models make completely opposing
claims concerning human mobility in the post-ENSO period. Humans either become
more sedentary or more mobile than they were earlier in the epoch according to
intensification or risk minimization respectively. However, PCM, patch choice, and MVT
indicate that risk minimization is the more tenable option for human mobility in the late
Holocene. Californian archaeological sites around the Santa Barbara Channel (Kennett,
2005; Raab and Larson, 1997; Kennett and Kennett, 2000) indicate that as patch quality
degraded in the late Holocene, indigenous groups became more mobile as proximate
foraging sites became exhausted through hunting and ENSO catalyzed climate changes.
24
Texas Tech University, Ethan C. Hill, May 2014
These sites have a far more complete archaeological record than Roonka Flat, making
these conclusions quite compelling. Since the environmental context of these sites is
strikingly similar to South Australia, they may serve as a good behavioral analog to the
Roonka sample.
Optimal foraging theory supports the risk minimization model in terms of human
populations becoming more mobile in response to environmental stress. However, when
considering the archaeological evidence presented above, OFT lends credence to the
intensification model in terms of sexual division of labor. Lourandos (1983, 1985, 1997)
posits that Australian populations intensified their economy and broadened their diet set
in response to a deteriorating environment. To better exploit diverse food items, societies
became more stratified with males and females contributing to the diet in different, but
complimentary, ways (Lourandos, 1983, 1985, 1997). O’Connell and Allen (2012) note
that as return rates fall on high-ranking food items, human foragers must intensify their
toolkit to incorporate items with higher handling costs. Processing technologies like
grindstones become more common in South Australia (Pretty, 1986), along with tulas
(Veth et al., 2011). Even Hiscock (2002, 2006) notes that backed artifacts have myriad
and diverse usages, allowing their users to exploit a wide range of resources effectively.
The archaeological evidence from South Australia supports a broader diet set.
Multiple sites in the Murray River basin display a wide range of food items (Pretty, 1977;
Smith, 1982; Lourandos, 1997). Further, high handling cost foods like shellfish are the
dominant food items in these sites, showing a heavy reliance on low return food items
(Pate, 2006). The dietary shift toward smaller-bodied game, more riverine resources, and
plant seeds is seen at other sites across Australia as well. Various authors have noted that
25
Texas Tech University, Ethan C. Hill, May 2014
during the late Holocene more dietary protein is obtained from small mammals, lizards,
and riverine mollusks than from large-bodied game (Smith, 1982; Morwood, 1987;
David, 1991; Lourandos, 1997; Hiscock, 2002; Attenbrow, 2004).
This evidence is consistent with OFT models presented above that indicate that as
diet sets expand, sexual division of labor becomes accentuated as males hunt
unpredictable game and females focus on reliable food sources (Bird, 1999; Waguespack,
2005; Bird et al., 2009). Larger game animals (kangaroos, wallabies, emus, etc.) became
less plentiful in the late Holocene, thus it is likely that sexual division of labor began to
become noted in populations in the Murray River valley. When large terrestrial protein
sources begin to diminish, females tend to incorporate lower ranking plant items with
higher handling costs, smaller-bodied animals, and freshwater shellfish into the diet
(Waguespack, 2005). This is consistent with archaeological evidence at Murray River
sites that shows an increase in these types of food sources (Pretty, 1977; Smith, 1978,
1982, Pate, 2006). Pate’s (1998a, b, 2000) isotope analyses support this further by
indicating reliance on freshwater protein (30-40%) in the Roonka diet as well as a large
range of terrestrial protein sources. The accumulation of these forms of evidence suggests
sexual differentiation of behavior became more pronounced during the late Holocene as
diet set broadened to incorporate varied food sources.
Purpose of study
The purpose of this study is to test predictions made by optimal foraging theory
and archaeological models concerning mobility and sexual division of labor in the
Roonka sample using external long bone diaphyseal dimensions. Research has
26
Texas Tech University, Ethan C. Hill, May 2014
demonstrated that behavioral ecology models have been useful in archaeological contexts
to make assumptions about human behavior (Kennett, 2005; Raab and Larson, 1997;
Kennett and Kennett, 2000; Bird and O’Connell, 2006; Bird et al., 2009). The
archaeological models and OFT hypotheses discussed above lead to two predictions that
can be tested through skeletal data (Table 1.1). First, if there is a decrease in quality
patches and high-ranking food items in the late Holocene, then Roonka lower limbs
should display more ovular diaphyses indicative of increased mobility. Second, if humans
at Roonka broadened their diet set during the late Holocene, then they should display
changes in upper limb bilateral asymmetry indicative of notable sexual division of labor.
TABLE 1.1. Testable predictions with supporting evidence from optimal foraging theory
and archaeological record
Prediction 1:
Roonka mobility increases in
post-ENSO period, lower limb
diaphyses become more ovular
Prediction 2:
Sexual division of labor becomes
more noted at Roonka post- ENSO,
sexes have differing upper limb
bilateral asymmetry patterns
Optimal Foraging Theory
PCM, MVT, and patch choice
predict expansion of foraging
radii in response to less
abundant patches
Archaeology
Expansion of backed artifact
tool kit facilitated an increase
in human mobility per risk
minimization model
Broadening diet breadth
required differing food
acquisition strategies between
the sexes
Processing technologies like
seed grinders indicate
increased sexual division of
labor per intensification
27
Texas Tech University, Ethan C. Hill, May 2014
CHAPTER II
MATERIALS AND METHODS
Roonka Flat sample
The Roonka Flat archaeological site is situated on the Murray River
approximately 8km North of Blanchetown, South Australia (Pretty, 1977; Prokopec,
1979). The site has four distinct archaeological phases, although only two yielded skeletal
remains (Pretty, 1977; Prokopec, 1979). While trench 1 of the South Dune on the East
bank of the Murray River contains Pleistocene archaeological deposits that represent
phase I, no skeletons were found (Pretty, 1977; Pretty, 1988). Phases II through IV are all
present in the Roonka Flat Dune and North Flat Dune on the West bank of the Murray
River (Pretty, 1977). Phase IV contains some archaeological remains from the historic
period (e.g. 200 bp – present), but no skeletal remains (Pretty, 1977). However, phases II
and III produced 216 skeletal individuals ranging from early to late Holocene (Pretty,
1977; Prokopec, 1979; Smith et al., 1988). While some material is severely eroded, about
60% of the individuals are fairly complete (Smith et al., 1988).
Some skeletons from the Roonka Flat Dune and the North Flat Dune cannot be
attributed to a particular time period, but fortunately most of the skeletons excavated
from Trench A of the Roonka Flat Dune fall into discreet cultural periods (Pretty, 1988).
Phase II (8 – 7 kya) contains fifteen individuals with only one individual of indeterminate
sex (Pretty, 1988; Smith et al., 1988; Author’s observations). Phase III further bisects into
two sub-phases: IIIa and IIIb (Pretty, 1988). Phase IIIa (6 – 4 kya) contains thirteen
skeletons, eight of which have determinable sex (Pretty, 1988). Phase IIIb (4 kya – 200
bp) contains 64 skeletal individuals with the majority having determinable sex (Pretty,
28
Texas Tech University, Ethan C. Hill, May 2014
1988). This study will combine phases II and IIIa into a pre-ENSO sample characteristic
of the early Holocene during the Australian climatic optimum. Phase IIIb, occurring after
the ENSO-induced environmental cooling and drying, will be referred to as the postENSO sample. This method best reflects the two predominant climates of the epoch.
(Table 2.1).
TABLE 2.1. Roonka Flat sample by period and sex
Pre-ENSO
Roonka II
male
A16
A37
A51
A63
A89
A91
A104
A105
A106
A107
Post-ENSO
Roonka IIIa
female
A13a
A36
A66
male
female
A61
A64
A108
A109
A7
A22
A38
A78
29
Roonka IIIb
male
female
A1
A4
A5a
A8a
A12a
A15
A18
A20
A21a
A23
A29
A30
A34
A45
A50
A56
A65
A80
A83
A85
A90
A92
A94
A13
A14
A28
A30a
A31
A32
A32a
A33
A54
A55
A75
A87
A96
Texas Tech University, Ethan C. Hill, May 2014
Most sex determinations have been previously published (Pretty, 1977, 1988),
however some individuals were included after sex diagnosis by the author while working
with the Roonka remains. A16 and A105 from Phase II, as well as A4 and A20 from
Phase IIIb are male individuals based on pelvic morphology. This was determined from
the greater sciatic notch and the subpubic angle on all individuals using methods in White
et al., (2012). Phase IIIb skeleton A13 was determined to be a female based on features of
the skull (White et al., 2012). Lastly, A29 was determined to be a male based on the
presence of an avulsed incisor, which is an Aboriginal cultural marker that has only been
seen in male individuals in the Australian archaeological record (Smith et al., 1988).
TABLE 2.2. Bones examined by period, sex, and individual
Humerus
Males
Pre-ENSO
Females
A16
A37
A51
A61
A63
A64
A89
A91
A104
A105
A107
A108
A109
A7
A13a
A36
A38
A66
A78
x
x
x
x
x
x
x
x
x
Ulna
Radius
x1
x
x
x
x1
x
x
x
x
x
x
x
Femur
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x2
x
30
x
x3
x
x5
x
x
x
x
x3
x
x
x
x
x
x4
x
x
x
x
1
Tibia
x
x
x
x
Texas Tech University, Ethan C. Hill, May 2014
TABLE 2.2. Cont.
A1
x
A4
x
x1
A5a
A12a
x
x
x3
x
x3
x
x
x
x
x
x
x
A15
A18
x
x
A20
Males
x
x
x
x
x5
A23
x
x1
x
x
x
A29
x
x
x
x
x
1
x
x
1
x
x
x
x
x
A30
A45
A50
A56
A80
x
x
x
x
1
x
x
1
x
x
1
x
x
x
x
x
x
x
A83
A85
x
x
x
x
x
A90
x
x
x
x
x4
A92
x
x1
x
x
x
x5
A13
A14
A28
x
x
x
x
x
1
x
x
x
1
x
x
x
x
x
x
x
x
x
x
A30a
A31
Females
x
x
x
x
x
x
x
A55
x
1
x
x
x
A75
x
x
x
A87
x
x
x
x
x
1
x
x
A32
A32a
A96
2
3
4
5
x3
x
1
A94
1
x
A21a
A34
Post-ENSO
x
x
x
x
x
These ulnae provided neck circumferences
Only one pre-ENSO female skeleton, A78, provided ulnar neck circumference data
Right side measurements substituted for left side
Measurements available for nutrient foramen, but not midshaft
Measurements available for midshaft, but not nutrient foramen
31
Texas Tech University, Ethan C. Hill, May 2014
Methods
The two predictions presented above will be tested through a battery of
measurements taken on the humeri, ulnae, radii, femora, and tibiae of the Roonka sample
(Table 2.2). All measurements used in this study are original data collected by the author
at the South Australian Museum annex at Hindmarsh in Adelaide, South Australia. Not
all individuals have the full complement of long bones represented due to random
preservation bias of skeletal material. The present analyses take this into account and thus
an individual may be included in one test and omitted in another depending on the
presence and condition of the bones of interest. Another concern with the analysis of
fragmentary skeletal material is that it can often be difficult to determine specific long
bone landmarks with accuracy, especially when finding locations like midshaft that
ideally require knowledge of total long bone length. However, the methodology used to
carry out these analyses attempts to minimize this concern through certain precautions
detailed below. Bones with landmarks that could not be determined with confidence were
omitted from this study.
Analysis of mobility: the femur and tibia.
First, an analysis of femoral and tibial external diaphyseal shape will allow the
comparison of mobility pattern changes from the early to late Holocene. Ruff (2000)
notes that the most revealing long bone studies are those that examine a population that
undergoes a shift in subsistence strategy. This isolates the influences of foraging behavior
on the human skeleton while factors such as terrain remain constant. If prehistoric
humans near the Murray River became relatively more mobile in the late Holocene then
32
Texas Tech University, Ethan C. Hill, May 2014
their bones will exhibit a more ovular shape. This will be examined by dividing
anteroposterior (AP) diameter by mediolateral (ML) diameter to create a diaphyseal
circularity index that concisely explains the relationship between AP and ML strains. A
value of 1 represents a circular cross section. The greater this value is above 1, the more
ovular the bone is. This reflects more physical strains exhibited in the AP plane.
Circumferences and AP diameters will also be presented for each sample to place shape
changes into context. These values provide a general indication of bone size, which
serves as a proxy for overall body size. If male and female distributions for these two
values remain consistent to one another over both time periods this will show that bone
size is not changing, further isolating changes in the diaphyseal circularity index.
Not only are diaphyseal circularity indices highly reflective of mobility (see
background), they are independent of standardization methods that are often used for
these analyses. Since bone robusticity is influenced by body size and shape, diaphyseal
properties are ideally standardized to bone length and an estimate of body weight
(Pearson, 2000; Ruff et al., 2006; Sparacello and Marchi, 2008). However, the
relationship between AP and ML diameter remains consistent regardless of whether the
results are standardized. Considering many skeletons in the Roonka collection lack
complete long bones or features to estimate body weight (femoral head diameter or biilliac breadth, Ruff et al., 1997), diaphyseal circularity indices were used in order to
provide the largest and most informative data set possible to examine changes in
Aboriginal mobility.
33
Texas Tech University, Ethan C. Hill, May 2014
TABLE 2.3. Measurements taken on Roonka femora and tibiae
Measurement (abbreviation)
Femur
Circularity index – midshaft anteroposterior diameter divided by mediolateral diameter
Midshaft anteroposterior diameter (AP diameter)
Midshaft circumference (Circumference)
Tibia
Circularity index – midshaft anteroposterior diameter divided by mediolateral diameter
Nutrient foramen circularity index (NF circ. index) – max diameter divided by mediolateral diameter
Midshaft anteroposterior diameter (AP diameter)
Midshaft circumference (Circumference)
Femoral diameters and circumferences were taken at midshaft (50% of maximum
bone length), while tibial diameters and circumferences were taken at midshaft and the
nutrient foramen (Table 2.3). When the exact location of midshaft had to be estimated
due to fragmentary remains, complete bones of similar length were used as analogs to
more precisely locate midshaft. The femoral diaphysis is largely uniform for most of its
length near midshaft (White et al., 2012), thus this landmark was often easy to locate
even in fragmentary femora. Tibial midshaft can be more difficult to locate if significant
portions of the bone, especially epiphyses, are missing. Thus, midshaft was only included
if other significant anatomical features were present to compare to an analog (e.g.
anterior tuberosity, soleal line, inferior termination of anterior crest). The inclusion of
measurements from the nutrient foramen allow for additional data on the tibia. Since
there is little bilateral asymmetry in the lower limbs (Auerbach and Ruff, 2006), the left
femur and tibia were used for each individual. If the left side was not present or did not
provide measurements the right side was substituted (see Table 2.2).
34
Texas Tech University, Ethan C. Hill, May 2014
To further isolate diaphyseal shape results, the present analysis also included
comparisons of anteroposterior diameter and circumference to serve as indicators of
overall diaphyseal robusticity. Including anteroposterior diameter and circumference for
the femur and tibia provides data for the average size of the long bone diaphysis. These
values are expected to be significantly different between sexes in both periods due to
normal sexual dimorphism in H. sapiens, but pre-ENSO averages should be similar to
post-ENSO averages for both sexes. Showing that there is no significant change in body
shape or stature between periods could bolster any significant results found in diaphyseal
circularity indices.
Analysis of sexual division of labor: the humerus, ulna, and radius.
An analysis of upper limb bilateral asymmetry will test whether sexual division of
labor became notable during the late Holocene. Data from the humerus, ulna, and radius
can be quite revealing of behavioral differences (Bridges, 1989; Trinkaus et al., 1994;
Bridges et al., 2000; Sparacello and Marchi, 2008; Shaw and Stock, 2009). Various tools
produce differential strains on the left and right arms. A thrown or thrust weapon
produces more right-biased forces than an implement such as a grindstone, which causes
more symmetrical muscle loads between the right and left sides. The extent of asymmetry
between the right and left sides in external diaphyseal dimensions is reflective of the
types of activities that an individual is performing frequently. If sexual division of labor
became more common in late Holocene South Australia, then it is likely that there will be
a notable difference between male and female upper limb bilateral asymmetry.
35
Texas Tech University, Ethan C. Hill, May 2014
TABLE 2.4. Measurements taken on Roonka humeri, ulnae, and radii
Measurement (abbreviation)
Humerus
Midshaft circumference bilateral asymmetry (Circum. asym.)
Midshaft maximum diameter bilateral asymmetry (Max dia. asym.)
Midshaft minimum diameter bilateral asymmetry (Min. dia. asym.)
Ulna
Anteroposterior diameter bilateral asymmetry at maximum extent of interosseus crest (AP dia. asym.)
Mediolateral diameter bilateral asymmetry at maximum extent of interosseus crest (ML dia. asym.)
Ulnar neck circumference bilateral asymmetry (Neck asym.)
Radius
Midshaft circumference bilateral asymmetry (Circum. asym.)
Midshaft anteroposterior diameter bilateral asymmetry (AP dia. asym.)
Midshaft mediolateral diameter bilateral asymmetry (ML dia. asym.)
The methods used to quantify bilateral asymmetry between the right and left sides
are detailed in Bridges (1989). Left-side measurements are divided by the right and then
multiplied by 100 to produce an asymmetry index. Maximum diameter, minimum
diameter, and circumference were measured at midshaft (50% of maximum bone length)
for the humerus and radius (Table 2.4). Ulnar maximum and minimum diameters were
taken at the greatest development of the interosseus crest (see White et al., 2012).
Circumference of the ulnar neck was also included in this study. However, only one
female from the pre-ENSO period yielded this measurement, thus omitting ulnar
circumference bilateral asymmetry from the pre-ENSO female sample.
This specific test necessitates that the same measurement be taken from the left
and right sides of the same individual. Therefore, right and left side measurements were
required for an individual to be included in the present analysis. Like measurements taken
on the femur and tibia, when upper limb remains were fragmentary an analogous
36
Texas Tech University, Ethan C. Hill, May 2014
individual with complete long bones was used to estimate midshaft. Ulnar dimensions are
easier to acquire as long as the diaphysis preserves the interosseus crest. This method of
analysis prevents measurement error by requiring the same measurements to be taken at
the same location on the right and left side.
Statistical methods.
Statistical assessment of mobility and sexual division of labor was conducted
using two-tailed t-tests for sex and time period. The male and female distributions were
compared to each other within each time period to examine sexual differences in
behavior. Further, early Holocene and late Holocene distributions for each sex were
compared to determine whether behavioral change was exhibited in both sexes equally or
in one more than the other. Aggregated sex sample for the pre-ENSO and post-ENSO
periods were also compared to determine populational level differences.
37
Texas Tech University, Ethan C. Hill, May 2014
CHAPTER III
RESULTS
Lower limb diaphyseal shape index results
TABLE 3.1. Sex comparison of femoral midshaft external dimensions
pre-ENSO
post-ENSO
Circularity index
Male mean
(n)
1.09 (11)
Female mean
(n)
1.01 (6)
0.04
Male mean
(n)
1.14 (18)
Female mean
(n)
1.09 (11)
0.15
AP diameter
28.09 (11)
23.87 (6)
0.01
28.96 (18)
25.05 (11)
0.0001
Circumference
85.55 (11)
75.67 (6)
0.01
87.00 (18)
77.18 (11)
0.0004
p1
p
1
Bolded p-value indicates statistically significant difference (p < 0.05) between male and female samples
using a two-tailed student’s t-test
TABLE 3.2. Temporal comparison of femoral midshaft external dimensions
pre-ENSO
Temporal
difference
post-ENSO
Mean
n
Mean
n
p1
Circularity index
1.06
17
1.12
29
AP diameter
26.60
17
27.48
29
0.03
0.63
Circumference
82.06
17
83.28
29
0.42
Circularity index
1.09
11
1.14
18
0.16
AP diameter
28.09
11
28.96
18
0.61
Circumference
85.55
11
87.00
18
0.51
Circularity index
1.01
6
1.09
11
AP diameter
23.87
6
25.05
11
0.01
0.58
Circumference
75.67
6
77.18
11
0.25
Population
Males
Females
1
Bolded p-value indicates statistically significant difference (p < 0.05) between pre-ENSO and post-ENSO
samples using a two-tailed student’s t-test
38
Texas Tech University, Ethan C. Hill, May 2014
Tables 3.1, 3.2, 3.3, and 3.4 provide circularity index results for the femur and
tibia. Sexual and temporal differences in circumference and anteroposterior diameter are
also presented for comparative purposes discussed above. A value of 1.00 represents a
circular cross section. As anteroposterior dimensions become more pronounced in
relation to mediolateral dimensions, this number increases.
Comparisons of male and female femoral circularity indexes between in the preENSO and post-ENSO show significant differences (Table 3.1). Pre-ENSO males and
females are significantly different from one another in their diaphyseal shape ratios (p =
0.04). The pre-ENSO female mean is almost completely circular, while the pre-ENSO
male mean reflects anteroposterior elongation of the diaphysis. However, the post-ENSO
sample presents non-statistically significant differences between the sexes, with postENSO males having slightly larger diaphyseal circularity index means than post-ENSO
females. Also, it is notable that the post-ENSO female circularity index mean is identical
to the pre-ENSO male circularity index mean. As expected, femoral midshaft
circumference and anteroposterior diameter are significantly different between the sexes
in both periods (Table 3.1). Male individuals are significantly larger than females in both
circumference (pre-ENSO, p = 0.01; post-ENSO, p = 0.0001) and anteroposterior
measurements (pre-ENSO, p = 0.01; post-ENSO, p = 0.0004).
Temporal differences in pre-ENSO and post-ENSO samples also yield
statistically significant results (Table 3.2). Populational, aggregate sex, comparisons
between pre-ENSO and post-ENSO show that circularity indexes are significantly larger
in the post-ENSO sample (p = 0.03). While post-ENSO males have somewhat larger
diaphyseal circularity ratios than pre-ENSO males, these results are not statistically
39
Texas Tech University, Ethan C. Hill, May 2014
significant. Post-ENSO females, however, have significantly different diaphyseal
circularity ratios from pre-ENSO females (p = 0.01). Post-ENSO females exhibit more
anteroposterior development of the femoral diaphysis than in the earlier period. Since
there are non-significant results between pre-ENSO and post-ENSO males, the
significant difference between the pre-ENSO and post-ENSO populational samples
seems to be primarily driven by changes in female diaphyseal circularity. Further, there is
little difference in overall bone size from the pre-ENSO to the post-ENSO in the
populational, male, or female samples. Post-ENSO circumference and anteroposterior
diameter means for the population and both sexes are somewhat larger than the preENSO, but these values are not statistically significant.
TABLE 3.3. Sex comparison of tibial midshaft and nutrient foramen external dimensions
pre-ENSO
post-ENSO
Male mean
(n)
1.46 (8)
Female mean
(n)
1.34 (5)
NF circ. index
1.56 (7)
1.57 (6)
AP diameter
29.38 (8)
Circumference
80.75 (8)
Circularity index
0.06
Male mean
(n)
1.41 (18)
Female mean
(n)
1.31 (10)
0.09
0.88
1.57 (17)
1.47 (10)
0.13
24.40 (5)
0.01
29.08 (18)
24.60 (10)
0.0001
72.40 (5)
0.02
82.78 (18)
72.70 (10)
0.00004
1
p1
p
Bolded p-value indicates statistically significant difference (p < 0.05) between male and female samples
using a two-tailed student’s t-test
40
Texas Tech University, Ethan C. Hill, May 2014
TABLE 3.4. Temporal comparison of tibial midshaft and nutrient foramen external
dimensions
Temporal
pre-ENSO
post-ENSO
difference
Mean
n
Mean
n
p1
Circularity index
1.41
13
1.37
28
0.38
NF circ. index
1.56
13
1.53
27
0.46
AP diameter
27.46
13
27.48
28
0.99
Circumference
77.54
13
79.18
28
0.52
Circularity index
1.46
8
1.41
18
0.43
NF circ. index
1.56
7
1.57
17
0.81
AP diameter
29.38
8
29.08
18
0.84
Circumference
80.75
8
82.78
18
0.53
1.34
5
1.31
10
0.53
NF circ. index
1.57
6
1.47
10
0.22
AP diameter
24.40
5
24.60
10
0.84
Circumference
72.40
5
72.70
10
0.88
Population
Males
Females
Circularity index
1
Bolded p-value indicates statistically significant difference (p < 0.05) between pre-ENSO and post-ENSO
samples using a two-tailed student’s t-test
Tables 3.3 and 3.4 present circularity index and bone size results for the tibia.
Sexual differences in midshaft and nutrient foramen diaphyseal shape are non-significant
in both the pre-ENSO and post-ENSO samples (Table 3.3). The nutrient foramen
circularity index is quite similar between pre-ENSO males and females with females
having a slightly larger mean value. Pre-ENSO males have larger midshaft circularity
indexes than pre-ENSO females. Although this sexual difference is not statistically
significant, it should be noted that the returned value for this t-test was .06, possibly
reflecting the same trends exhibited in pre-ENSO femoral circularity indexes. Similarly,
post-ENSO males have larger circularity indexes than post-ENSO females, but this value
41
Texas Tech University, Ethan C. Hill, May 2014
is not statistically significant. Like femoral results above, anteroposterior diameter (preENSO, p = 0.01; post-ENSO, p = 0.0001) and tibial midshaft circumference (pre-ENSO,
p = 0.02; post-ENSO, p = 0.00004) are significantly different between the sexes in both
the pre-ENSO and post-ENSO samples. Again, males are larger than females in these
measurements.
Population sample comparisons between pre-ENSO and post-ENSO circularity
indexes do not return statistically significant results, but the post-ENSO population
means are slightly smaller than pre-ENSO means in midshaft and nutrient foramen
circularity indexes (Table 3.4). This same trend is seen in both sexes with post-ENSO
males and females having somewhat lower values than the corresponding pre-ENSO
male and female samples. However, none of these values reach statistical significance.
Further, there is little temporal difference in anteroposterior diameter or circumference
between pre-ENSO and post-ENSO samples of either sex. Post-ENSO male
anteroposterior diameter and circumference are slightly larger than pre-ENSO male
values and pre-ENSO and post-ENSO female means for these measurements are almost
identical, but none of these values are significant. Pre-ENSO and post-ENSO
populational comparisons are also not statistically significant.
Upper limb bilateral asymmetry results
Bilateral asymmetry results for the bones of the upper limb are presented below
(Tables 3.5, 3.6, 3.7, 3.8, 3.9, and 3.10). A value of 100 represents complete symmetry
and decreases as right-side asymmetry becomes more noted. Therefore, right-side
dominance is more pronounced as these values get smaller.
42
Texas Tech University, Ethan C. Hill, May 2014
TABLE 3.5. Sex comparison of humeral midshaft bilateral asymmetry results 1
pre-ENSO
post-ENSO
Circum. asym.
Male mean
(n)
96.30 (9)
Female mean
(n)
98.16 (5)
0.31
Male mean
(n)
94.48 (14)
Female mean
(n)
98.26 (9)
Max dia. asym.
94.27 (9)
Min. dia. asym.
97.77 (9)
95.18 (5)
0.67
92.59 (14)
98.83 (9)
98.70 (5)
0.68
94.63 (14)
96.62 (9)
p2
p
0.001
0.001
0.26
1
Bilateral asymmetry acquired by dividing left side by right side measurement then multiplying by 100
(Bridges, 1989), value of 100 signifies symmetry of right and left sides
2
Bolded p-value indicates statistically significant difference (p < 0.05) between male and female samples
using a two-tailed student’s t-test
TABLE 3.6. Temporal comparison of humeral midshaft bilateral asymmetry results 1
pre-ENSO
Temporal
difference
post-ENSO
Mean
n
Mean
n
p2
Circum. asym.
96.97
14
95.96
23
0.36
Max dia. asym.
94.59
14
95.03
23
0.77
Min. dia. asym.
98.10
14
95.41
23
0.06
Circum. asym
96.30
9
94.48
14
0.19
Max dia. asym.
94.27
9
92.59
14
0.40
Min. dia. asym.
97.77
9
94.63
14
0.11
Circum. asym
98.16
5
98.26
9
0.95
Max dia. asym.
95.18
5
98.83
9
0.07
Min. dia. asym.
98.70
5
96.62
9
0.34
Population
Males
Females
1
See table 3.5 for methods used to measure bilateral asymmetry
Bolded p-value indicates statistically significant difference (p < 0.05) between pre-ENSO and post-ENSO
samples using a two-tailed student’s t-test
2
Asymmetry results for the humerus are presented in tables 3.5 and 3.6. Pre-ENSO
males have slightly more right-side asymmetry than pre-ENSO females in all three
measurements, but none of these values are statistically significant (Table 3.5). Inversely,
43
Texas Tech University, Ethan C. Hill, May 2014
post-ENSO males and post-ENSO females show statistically significant differences in
two of the three measurements. Midshaft circumference (p = 0.001) and maximum
diameter (p = 0.001) return significantly different values with post-ENSO males being
more asymmetric than post-ENSO females. Although post-ENSO males are more
asymmetric in midshaft minimum diameter than post-ENSO females, this value is not
significantly different. While post-ENSO males exhibit right-side asymmetry, post-ENSO
females are more symmetric in all three measurements with midshaft circumference and
maximum diameter being close to 100.
There are no statistically significant temporal differences between pre-ENSO and
post-ENSO populational samples in any of the three measurements (Table 3.6). The postENSO population sample is slightly more asymmetric in midshaft circumference and
minimum midshaft diameter measurements than the pre-ENSO population sample, but is
more symmetric in maximum midshaft diameter dimensions. However, it is worth noting
that the difference in minimum midshaft bilateral asymmetry between pre-ENSO and
post-ENSO population samples returned a p-value of 0.06. Further, temporal differences
in bilateral asymmetry results are not statistically significant in either sex. Pre-ENSO
males show a slight trend toward asymmetry from post-ENSO males in all three
measurements, but none of these values are statistically significant. Likewise, post-ENSO
females are more symmetric than pre-ENSO females in midshaft circumference and
maximum diameter while minimum midshaft diameter becomes more asymmetric.
Although pre-ENSO females and post-ENSO females are not statistically different in any
measurement, it is notable that maximum midshaft diameter returned a p-value of 0.07.
44
Texas Tech University, Ethan C. Hill, May 2014
TABLE 3.7. Sex comparison of ulnar bilateral asymmetry results 1
pre-ENSO
post-ENSO
AP dia. asym.
Male mean
(n)
94.08 (10)
Female mean
(n)
98.33 (3)
0.10
Male mean
(n)
100.71 (13)
Female mean
(n)
100.39 (6)
0.93
ML dia. asym.
93.93 (10)
Neck asym.
97.70 (3)
89.20 (3)
0.18
93.54 (13)
99.45 (6)
0.12
–3
–
96.54 (9)
98.31 (4)
0.69
p2
p
1
See table 3.5 for methods used to measure bilateral asymmetry
Bolded p-value indicates statistically significant difference (p < 0.05) between male and female samples
using a two-tailed student’s t-test
3
Only one pre-ENSO female had both ulnar necks present, not adequate for statistical test
2
TABLE 3.8. Temporal comparison of ulnar bilateral asymmetry results 1
pre-ENSO
Temporal
difference
post-ENSO
Mean
n
Mean
n
p2
AP dia. asym.
95.06
13
100.61
19
ML dia. asym.
92.84
13
95.41
19
0.01
0.33
Neck asym.
97.70
3
97.09
13
0.86
AP dia. asym
94.08
10
100.71
13
ML dia. asym.
93.93
10
93.54
13
0.02
0.90
Neck asym.
97.70
3
96.54
9
0.78
AP dia. asym
98.33
3
100.39
6
0.56
ML dia. asym.
89.20
3
99.45
6
–
98.31
4
0.02
–
Population
Males
Females
Neck asym.
–
3
1
See table 3.5 for methods used to measure bilateral asymmetry
Bolded p-value indicates statistically significant difference (p < 0.05) between pre-ENSO and post-ENSO
samples using a two-tailed student’s t-test
3
Only one pre-ENSO female had both ulnar necks present, not adequate for statistical test
2
Bilateral asymmetry results for the ulna are shown in tables 3.7 and 3.8.
Statistically significant sexual differences are not present in either the pre-ENSO or postENSO samples (Table 3.7). Sexual differences between pre-ENSO and post-ENSO
45
Texas Tech University, Ethan C. Hill, May 2014
samples do not follow any discernable patterns. Pre-ENSO females display more
symmetry than pre-ENSO males in anteroposterior diameter, but are less symmetric in
mediolateral diameter. Since only one female, A78, had both ulnae with the ulnar neck
present, pre-ENSO sexual comparisons could not be made on neck circumference. PostENSO females are more symmetric than post-ENSO males in two measurements:
mediolateral diameter and neck circumference. Anteroposterior diameter values are
almost identical between post-ENSO males and post-ENSO females.
However, temporal differences between pre-ENSO and post-ENSO samples
produce statistically significant results. The post-ENSO populational sample is
significantly more symmetric in anteroposterior diameter than the pre-ENSO
populational sample (p = 0.01). Mediolateral diameter is also more symmetric in the postENSO populational sample, but this difference is not statistically significant. There is
virtually no difference between neck circumference asymmetry values between the preENSO and post-ENSO populational samples, but the pre-ENSO populational sample for
this measurement is only represented by male individuals due to the paucity of female
representatives. This trend is also seen in males with anteroposterior diameter values
being significantly more symmetric in post-ENSO male than pre-ENSO males (p = 0.02).
Post-ENSO male values for mediolateral diameter and neck circumference are quite
similar to pre-ENSO males. Post-ENSO females are slightly more symmetric in their
anteroposterior diameter values than pre-ENSO females, but are significantly more
symmetric in mediolateral diameter measurements (p = 0.02).
46
Texas Tech University, Ethan C. Hill, May 2014
TABLE 3.9. Sex comparison of radial midshaft bilateral asymmetry results 1
pre-ENSO
post-ENSO
Circum. asym.
Male mean
(n)
97.00 (6)
Female mean
(n)
97.31 (5)
0.90
Male mean
(n)
100.05 (10)
Female mean
(n)
96.26 (6)
0.18
AP dia. asym.
96.50 (7)
ML dia. asym.
95.60 (7)
93.54 (5)
0.48
95.64 (10)
93.34 (6)
0.39
98.98 (5)
0.34
98.33 (10)
94.52 (6)
0.11
p2
p
1
See table 3.5 for methods used to measure bilateral asymmetry
Bolded p-value indicates statistically significant difference (p < 0.05) between male and female samples
using a two-tailed student’s t-test
2
TABLE 3.10. Temporal comparison of radial midshaft bilateral asymmetry results 1
pre-ENSO
Temporal
difference
post-ENSO
Mean
n
Mean
n
p2
Circum. asym.
97.14
11
98.63
16
0.39
AP dia. asym.
95.27
12
94.78
16
0.84
ML dia. asym.
97.01
12
96.90
16
0.96
Circum. asym
97.00
6
100.05
10
0.26
AP dia. asym.
96.50
7
95.64
10
0.81
ML dia. asym.
95.60
7
98.33
10
0.38
Circum. asym
97.31
5
96.26
6
0.68
AP dia. asym.
93.54
5
93.34
6
0.95
ML dia. asym.
98.98
5
94.52
6
0.15
Population
Males
Females
1
See table 3.5 for methods used to measure bilateral asymmetry
Bolded p-value indicates statistically significant difference (p < 0.05) between pre-ENSO and post-ENSO
samples using a two-tailed student’s t-test
2
No statistically significant results were reported for the radius (Tables 3.9 and
3.10). Pre-ENSO males are somewhat more asymmetric than pre-ENSO females in
midshaft circumference and midshaft mediolateral diameter, but less asymmetric in
midshaft anteroposterior diameter (Table 3.9). Post-ENSO males are more symmetric
47
Texas Tech University, Ethan C. Hill, May 2014
than post-ENSO females in all dimensions, but none of these values are statistically
significant.
Comparisons between pre-ENSO and post-ENSO populational samples yield
similar results. Post-ENSO males become more symmetric in midshaft circumference and
midshaft mediolateral diameter than pre-ENSO males, while midshaft anteroposterior
diameter becomes slightly more asymmetric. Post-ENSO females become slightly more
asymmetric than pre-ENSO females across all three measurements. However, none of
these temporal changes between pre-ENSO and post-ENSO samples reach statistical
significance.
48
Texas Tech University, Ethan C. Hill, May 2014
CHAPTER IV
DISCUSSION
Mobility implications from lower limb circularity results
To briefly revisit the hypothesis presented above for the lower limbs; if overall
environmental quality deteriorated after ENSO establishment, then the individuals at
Roonka corresponding to the post-ENSO period should display bone functional
adaptations for increased mobility. The results presented above for the lower limb
support this hypothesis. Circularity indices for the tibia did not return statistically
significant results, but this was expected based on the literature. Bone functional
adaptation of the tibia to increased mobility is more likely to influence cortical bone area
than bone shape (Stock, 2006), although it is pertinent to again note that the difference in
tibial midshaft circularity index values between pre-ENSO males and females returned a
p-value of .06. This is possibly reflective of the same pattern seen in pre-ENSO
differences between male and female circularity indexes.
Unlike the tibiae, Roonka femora returned significant results that reflect both
sexual and temporal behavioral differences. Increased femoral diaphyseal shape in the
post-ENSO pooled-sex sample indicates that the Roonka population became more mobile
over time. Further, this appears to be primarily the result of changes in female, rather than
male, mobility. The significant increase in the female femoral circularity index during the
post-ENSO period reflects a more ovular diaphysis, signifying intensified mobility over
time that is not seen in the male sample. This change in female mobility during the postENSO period brings them more in line with male mobility so much so that female
circularity indexes are not significantly different from males. This is a notable change
49
Texas Tech University, Ethan C. Hill, May 2014
from the pre-ENSO sample where male and female mobility patterns produced
significantly different femoral shape ratios. In this earlier period, female shape indices
close to 1.00 indicate a more sedentary existence, while their male counterparts are more
mobile. These results indicate that post-ENSO population mobility dynamics became
substantively altered from earlier periods.
Sexual division of labor implications from upper limb bilateral asymmetry results
Results from the upper limbs complement the dramatic population dynamic
changes seen in the lower body. To reiterate the hypothesis for the upper limbs; if people
at Roonka broadened their diet set in the post-ENSO period in response to lower
abundance of high-ranking food items, then they should display notable sexual division
of labor. Again, present results support the stated hypothesis. None of the tests performed
on the upper limbs returned significant differences between sexes in the pre-ENSO
period. This indicates that males and females performed largely similar tasks at similar
levels of intensity, producing comparable levels of upper limb bilateral asymmetry in all
three bones examined. The pre-ENSO period appears to be a period defined by relatively
less sexual division of labor.
However, a reverse in this trend characterizes the post-ENSO period. Humeral
bilateral asymmetry results indicate that sexual division of labor became more prevalent
during this later period. While neither sex’s asymmetry results are significantly changed
from the pre-ENSO period, males trend toward more asymmetry and females become
more symmetric in most of their dimensions (however, the temporal difference in female
maximum midshaft diameter returned a p-value of 0.07). The fact that midshaft
50
Texas Tech University, Ethan C. Hill, May 2014
maximum diameter is significantly different between the sexes is particularly interesting
considering this dimension has more potential to be influenced by flexion and extension
movements of the arm (Bridges, 1989; Bridges et al., 2000; Sparacello and Marchi, 2008;
Weiss, 2009). Post-ENSO male maximum midshaft diameter was the most asymmetric
value from any of the humeral measurements, while post-ENSO females returned the
most symmetric value for maximum midshaft diameter. A similar trend is seen in
midshaft circumference, potentially an indicator of overall upper arm use. These results
strongly indicate that males were performing tasks that necessitated asymmetric upper
body loadings, while females primarily carried out movements that required equal
loading from the right and left arms during the post-ENSO period.
Results from the lower arm are more difficult to interpret. The radius did not
provide any illuminating data, but the ulna returned significant results that are somewhat
inconsistent with humeral results. Data that support increasing symmetry in females
during the post-ENSO period can be found in ML diameter measurements. This is
completely in line with results from the humerus. However, males also exhibit one
measurement, AP diameter, which becomes significantly more symmetric later in time.
This runs counter to male humerus results.
While some attempts will be made below to explain what behaviors could create
upper arm asymmetry and lower arm symmetry in the post-ENSO male sample, the
majority of this study’s discussion will focus on implications of humeral results. Shaw
and Stock (2007) note that ulnar external diaphyseal measurements sometimes do not
properly reflect internal cross-sectional dimensions due to variable development of the
interosseus crest. Diaphyseal measurements can be skewed depending on the size and
51
Texas Tech University, Ethan C. Hill, May 2014
orientation (e.g. crest may be displaced anteroposteriorly) of the interosseus crest (Stock
and Shaw, 2007). Further, some research may indicate that bilateral asymmetry in bone
length may be more informative for the lower arm (Auerbach and Ruff, 2006).
Unfortunately, the fragmentary nature of the Roonka sample omitted any potential
analysis based on long bone length. Due to these reasons, ulnar results must be
interpreted with some degree of caution.
Pre-ENSO behavior at Roonka Flat
Together these results indicate that the Roonka population became more mobile
and exhibited increased sexual division of labor after the establishment of ENSO.
Further, this analysis is particularly interesting considering that both upper and lower
limb results indicate that these changes in behavior were more pronounced in female
members of the population. The more abundant and evenly spread patches produced by
the warmer and wetter climate of the early Holocene were conducive to relatively more
sedentism, especially by females considering the above results. These “sweet spot”
patches were able to support more large game animals such as kangaroos, wallabies, and
emus (Pretty, 1986; Gagan et al., 2003; Bird et al., 2009; O’Connell and Allen, 2012).
Further, patches containing quality game animals were compactly distributed throughout
the environment (Bird et al., 2009; O’Connell and Allen, 2012). Even if there were
frequent travel between patches, predicted by MVT, it would be offset by small foraging
radii (Charnov, 1976; Stephens et al., 2007).
The risk minimization model also predicts smaller foraging radii and overall less
mobility prior to ENSO establishment. Although Hiscock’s (1994, 2002, 2006) model is
52
Texas Tech University, Ethan C. Hill, May 2014
primarily concerned with post-ENSO behavior changes toward increased mobility in
response to environmental fluctuation, it follows that relative climatic stability would
produce more sedentary populations. These predictions of less mobility during the preENSO period are borne out by the results above.
The significant difference between male and female mobility during the preENSO period is probably due to a diet that relied more on large game animals. Since
large game was more stable and abundant, there would have been less need for lower
ranking resources in the pre-ENSO period (Waguespack, 2005; Bird et al., 2009;
O’Connell and Allen, 2012). The archaeological evidence from the early Holocene
supports this position with deposits that consist almost entirely of large and medium sized
game animals, as well as freshwater shellfish (Pretty, 1977, 1986; Smith, 1982). If a large
proportion of the diet was comprised primarily of large terrestrial protein, it makes sense
that males were more mobile than females to pursue these game animals (Bird, 2009;
Waguespack, 2005; Stephens et al., 2007).
Although there were differences in mobility between the sexes, results from the
upper limbs indicate that there were no significant differences in bilateral asymmetry
during the pre-ENSO period. The activities that males and females were performing in
the early Holocene were producing a slight right side bias. Even though females were not
as mobile, these results potentially indicate that females were responsible for some
hunting duties. Even opportunistic hunting of small and medium sized game could
explain this amount of asymmetry (Bridges, 1989; Bridges et al., 2000). Further, if males
and females were both involved in processing animal remains (e.g. cleaning pelts,
butchering meat, etc.), then the use of bifacial scrapers could also explain this right-side
53
Texas Tech University, Ethan C. Hill, May 2014
bias (Pretty, 1977, 1986; Hiscock, 2002, 2006). Granted, the paucity of archaeological
remains in the early Holocene makes any additional interpretations for this period
difficult.
Post-ENSO behavior at Roonka Flat
Whereas interpretations of behavior in the pre-ENSO period must be tempered,
archaeological evidence from the late Holocene is denser, allowing a more complete
image of post-ENSO behavior to become apparent. Femoral circularity indices indicate
that there is a general populational increase in mobility in the Roonka sample. Further, as
noted above, females are the primary driver of this shift in mobility since their values
significantly change over time. Male circularity indices increase as well, but not
significantly. It is particularly interesting that post-ENSO male and female circularity
indices are not significantly different, meaning that differences in mobility between the
sexes was marginal. These data together provide evidence that populations in the Murray
River valley became more mobile after the establishment of ENSO.
In fact, this is exactly what is predicted by OFT. As environmental conditions
deteriorated in the post-ENSO period, overall patch quality declined (Shulmeister and
Lees, 1995; Hiscock, 2002; Gagen et al., 2003). Not only were patches less abundant,
they were also sparser across the landscape and contained less high-ranking food items
(Bird, 1999; Bird et al., 2009; O’Connell and Allen, 2012). Large and medium sized
game animals were less plentiful within patches and were exploited rapidly, meaning that
individuals had a limited amount of time that they could forage in a particular patch so as
not to deplete choice resources (Charnov, 1976; Stephens et al., 2007). South Australians
54
Texas Tech University, Ethan C. Hill, May 2014
living in the Murray River valley would have responded by expanding their foraging radii
and incorporating lower ranking items into their diet.
The risk minimization model also predicts an increase in populational mobility in
order to expand foraging radii (Hiscock, 1994, 2002, 2006). The flexibility of a backed
artifact-dominated tool set allowed prehistoric Australians to be mobile as a means to
offset ENSO-induced climatic instability (Hiscock, 1994, 2002, 2006). A small, yet
functionally diverse, toolkit would have facilitated a non-sedentary lifestyle. Regional
archaeological evidence from South Australia lends credence to this as well. Not only
does backed artifact use expand significantly in the late Holocene, bone implements
proliferate as stone tools decline in use (Pretty, 1986, 1988; Pate, 2006). Backed artifacts
and bone tools provided a lightweight, yet versatile tool kit that facilitated increased
mobility (Hiscock, 1994, 2006; Veth et al., 2011).
Although the increased visibility of seed grinders in South Australia during the
late Holocene might seem contradictory, it actually supports increased mobility (Pretty,
1977, 1986, 1988). A sedentary population uses a grinder until it is too worn down to
function while a mobile population uses a grinder until it is necessary to move again, at
which point the implement will be discarded (Veth and O’Connor, 1996; Gorecki et al.,
1997; Balme et al., 2001). This latter situation provides an archaeologically intact grinder
while the former does not.
Since the skeletal data above support the risk minimization model in terms of
mobility patterns, alliance and territory formation do not appear to be tenable views
concerning human culture at Roonka (Lourandos, 1983, 1997). Hiscock’s (1994, 2002,
2004) suggestion that post-ENSO populations lived in small foraging bands is more
55
Texas Tech University, Ethan C. Hill, May 2014
acceptable. This further bolsters Littleton and Allen’s (2007) claim that Roonka is a
cemetery site where multiple mobile foraging groups buried their deceased, rather than
the cemetery of a sedentary population inhabiting the site over the Holocene.
While the evidence supports relative equality in male and female mobility,
bilateral asymmetry results indicate sexual division of labor was more prevalent and
notable in the post-ENSO period. This appears to be the result of a broader diet set
compared to the pre-ENSO period. The late Holocene regional archaeological record
shows a much wider range of food remains than the early Holocene (Smith, 1978; Pate,
2006). Not only are large and medium game animals being hunted, small mammals and
lizards are also frequently captured (Pretty, 1977; Smith, 1982; Pate, 2006). There is also
evidence of more frequent and diverse exploitation of riverine resources like fish,
shellfish, and mussels (Pretty, 1977; Smith, 1982; Pate, 2006). Further, a wide range of
food producing plants could have been used (Pate, 2006). Pate’s (1998a,b, 2000, 2006)
paleodietary research on bone collagen also supports the inclusion of various protein
resources into the diet.
The skeletal evidence supports the OFT prediction that the incorporation of low
ranking resources into the Roonka diet set would lead to more sexual division of labor
(Waguespack, 2005; O’Connell and Allen, 2012). The incorporation of low ranking, high
handling-cost foods into the human diet often involves unequal participation between the
sexes, with males maintaining a focus on high ranking resources while females
incorporate lower ranking foods (Waguespack, 2005; O’Connell and Allen, 2012). This is
reflected in the above data with a significant difference in upper limb bilateral asymmetry
between the sexes in the post-ENSO period.
56
Texas Tech University, Ethan C. Hill, May 2014
The relative symmetry found in the female upper limb is best explained by the
incorporation of high handling cost foods into the diet, more specifically, the tools used
in order to process and exploit said foods. Not only do seed grinders become more
common in South Australia in the post-ENSO period (Pretty, 1986), they proliferate
throughout much of the continent during this same span (Veth and O’Connor, 1996;
Gorecki et al., 1997; Balme et al., 2001; Hiscock, 2002). Seeds provide a stable, but high
handling cost, food resource that would have made an important dietary contribution in
the unstable and less abundant patches of post-ENSO South Australia (Hiscock, 2002).
Ethnographic evidence after European contact suggests that seeds were obtained from a
wide variety of acacias, eucalypts, grasses, sedges, and small shrubs (Mulvaney and
Kamminga, 1999). Considering that these plant varieties were available throughout the
Murray River valley and surrounding locales throughout the late Holocene (Singh and
Luly, 1991; Shulmeister and Lees, 1995; Pate, 2006), it is likely that foragers at Roonka
were utilizing these plants.
Although not readily preserved, historical accounts from European settlers note
that “digging sticks” were quite common in Aboriginal societies throughout the continent
(Davidson, 1936; Flood, 1999). Digging sticks were frequently used by women in these
populations to uncover tubers and other edible roots (Davidson, 1936; Flood, 1999). Like
seed grinding, digging for tubers and roots required a significant amount of devoted time.
If diet indeed broadened during the late Holocene, the incorporation of reliable, but low
ranking, tubers and roots made a stable addition to the human diet.
The pushing and pulling motions required to use a seed grinder and the digging
motion of digging sticks involve equal participation of the right and left arms. This is
57
Texas Tech University, Ethan C. Hill, May 2014
reflected in the results for the upper limb presented above. In particular, the arm
extension required in pushing motions can explain the bilateral symmetry displayed in
post-ENSO Roonka humeri. Further, this trend is equally displayed in the lower arm with
ulnar measurement also showing a significant shift toward increased symmetry in
females. These data support the claim that the incorporation of high handling cost foods
in the post-ENSO period led to increased sexual division of labor, since the present
evidence indicates that females became unequally involved in processing tasks.
However, this is not to say that women did not also contribute opportunistic game
and riverine resources. The archaeological evidence for increased diet set indicates that
these were well represented in the diet (Pretty, 1977; Smith, 1982; Pate, 2006), and it is
likely that women were integral in the collection of these food items (Waguespack,
2005). Bone remodeling is influenced by the duration, frequency, and intensity of the
action being performed (Ruff, 2000; Ruff et al., 2006). Therefore, even though female
contribution to the diet was probably varied, activities involved with food processing and
digging up roots and tubers were demanding and required a substantial devotion of time.
While post-ENSO Roonka females focused on incorporating low ranking
resources into the diet, humeral bilateral asymmetry in post-ENSO males supports the
OFT prediction that males maintained a focus on large and medium sized game. Perhaps
counter intuitively; as high-ranking game animals become less abundant in the
environment males will often intensify their efforts in hunting these risky, but high
yielding, food resources (Waguespack, 2005; Bird and O’Connell, 2006; Bird et al.,
2009). Further, Waguespack (2005) notes that the increased exploitation of seeds and
nuts is often correlated with greater efforts to include large terrestrial game animals into
58
Texas Tech University, Ethan C. Hill, May 2014
the diet. Considering the evidence above supporting reliance on seed processing
technologies, increased male attention to hunting game could be a viable explanation for
their significant right-side dominance compared to females.
Various hunting implements are found in the late Holocene archaeological record
throughout South Australia. Backed artifacts, when hafted, were frequently used as spears
to hunt game (Slack et al., 2004; Robertson, 2005; Hiscock, 2006). It has also been
suggested based on ethnographic evidence and resin residue left on archaeological
remains that backed artifacts were hafted into “death spears” (Kamminga, 1980;
Mulvaney and Kamminga, 1999; Flood, 2001; McDonald et al., 2007). Death spears
consisted of one or two rows of backed artifacts mounted backwards along the shaft of a
spear, making a barbed tip that made removal almost impossible and leading to severe
blood loss (Kamminga, 1980; Mulvaney and Kamminga, 1999; Flood, 2001; McDonald
et al., 2007). Use-wear analyses have suggested that these implements were not only used
for hunting purposes, but also in warfare or the ritual murder of other people (Kamminga,
1980; Robertson, 2005; McDonald et al., 1994, 2007).
Further, bone points were also used to manufacture projectile spears, potentially
used with a woomera, or spear-thrower (Pretty, 1986; Pate, 2006). It is also likely that
wooden implements were represented in this tool kit. Although deposits at Wyrie Swamp
date to the early Holocene, it is plausible that thrown implements such as boomerangs
and fire-hardened wooden spears continued to be utilized (Hiscock, 1994, 2006). These
are widely depicted in rock art around the continent, and upon contact were noted to be
ubiquitous within South Australian Aboriginal culture (Flood, 1999). The use of spear
throwers, thrusting spears, and boomerangs were noted to be used almost exclusively by
59
Texas Tech University, Ethan C. Hill, May 2014
males in ethnographic accounts (Abbie, 1969; Tonkinson, 1978). The use of wooden
clubs in South Australia is also noted in ethnographic sources after European colonization
(Davidson, 1936, Abbie, 1951). Two main types of wooden clubs are found in South
Australia: smaller thrown clubs, and larger handheld war clubs (Davidson, 1936; Abbie,
1951). The former type was used primarily for hunting while the latter was used in inter
and intra-group fighting (Davidson, 1936; Abbie, 1951). Hunter-gatherers in the Murray
River valley were frequently seen using these smaller wooden clubs to beat emus to death
after subduing them with nets (Beveridge, 1883).
Considering the wide range of tools and weapons available throughout the postENSO period, male asymmetry of humeral dimensions is easily explained. However, as
was discussed above, the results of the lower arm seem to contradict humeral results.
Although one would expect results from the lower arm to mirror the upper arm, the
humerus and ulna do not necessarily have to present the same results. Some activities,
like the pushing motion involved in seed grinding, require the use of upper and lower
arm, but this is not a requirement for all movements. While lower arm results need to be
interpreted with caution, the proliferation of tulas during the late Holocene could
potentially explain the relative bilateral symmetry of male lower arms while not
contradicting asymmetry of the humeri.
Tulas are flake-stone adzes that proliferated with the larger backed artifact
tradition (Veth et al., 2011). Tulas were primarily hafted to a large handle and used to
shave and incise wood, especially the hard woods of acacias and eucalypts (Mulvaney
and Kamminga, 1999; Veth et al., 2011). Slightly smaller varieties of this tool were also
used to work animal hides and fibrous plant material such as bark (Mulvaney and
60
Texas Tech University, Ethan C. Hill, May 2014
Kamminga, 1999; Veth et al., 2011). In both cases, the tool is used by drawing the adze
toward one’s body in a pulling motion using both hands (Fig. 4.1) (Mulvaney and
Kamminga, 1999). This tool involves the use of both arms, but not in the same way as a
grindstone. Tula use avoids the pushing motion of grinding and thus the strains involved
with use are localized to the forearms and back. The upper arm does not serve an integral
role in this action. Thus, the act of using a tula would not influence bilateral asymmetry
of the humerus.
Fig. 4.1. Depiction of typical tula use. Note that the implement is being drawn toward the user (from
Mulvaney and Kamminga, 1999)
Whether tula use accurately explains the unique bilateral asymmetry pattern seen
in post-ENSO males, the sexual difference between male and female humeral bilateral
asymmetry remains valid. The hypothesis of increased sexual division of labor in the
61
Texas Tech University, Ethan C. Hill, May 2014
post-ENSO period is supported by the above results, OFT, and the archaeological
evidence. Although mobility results tend to support risk minimization, these findings for
sexual division of labor support the intensification model of behavioral change
(Lourandos, 1983, 1985, 1997; David and Lourandos, 1998). Sexual division of labor
became necessary to exploit lower ranking resources during times of climatic instability,
especially foods such as seeds, fish, and mollusks (Bowdler, 1981; Flood, 1980;
Lourandos 1983, 1985, 1997). Diversifying food procurement strategies between the
sexes allowed males to focus on risky, high calorie yielding foods while females
incorporated stable and processing-intensive foods (Bowdler, 1981; Flood, 1980;
Lourandos 1983, 1985, 1997). This focal difference may also be reflected in the carbon
isotope differences between the sexes with males consuming slightly more terrestrial
proteins (Pate, 1998a,b, 2000).
While part of the intensification model is supported by sexual division of labor,
evidence for increased mobility above casts doubt on other aspects of this model. If
populations at Roonka were not sedentary in the late Holocene, it does not seem likely
that they became more territorial or exhibited “closed” social systems as Lourandos
(1983, 1985) posits. Normally human populations that are mobile have more flexible
social structure and perceptions of group identity (Bird et al., 2009; O’Connell and Allen,
2012). Mobile human groups frequently aggregate into larger communities when
environmental conditions allow, but will also split into smaller groups when resources are
scarce (Bird et al., 2009; O’Connell and Allen, 2012). Things like cemeteries and rock art
most likely do not reflect territorialized sedentary groups that were trying to control
certain resources in the environment. However, the presence of wooden war clubs and
62
Texas Tech University, Ethan C. Hill, May 2014
death spears indicates that violent conflicts were occurring, at least occasionally,
throughout the post-ENSO period (Davidson, 1936; Mulvaney and Kamminga, 1999;
McDonald et al., 2007).
A cross-sectional study by Carlson et al. (2007) further bolsters the conclusions of
this study. Their examination of 149 geographically heterogeneous pre- and post-contact
Aboriginal skeletons yielded results indicating that Australian foragers tend to exhibit
noted sexual division of labor and increased mobility (Carlson et al., 2007). Further, in
accordance with this study’s conclusions, men and women normally exhibit relatively
equal levels of foraging mobility (Carlson et al., 2007). Although males were responsible
for pursuing and hunting large game animals, women commonly comprised a significant
portion of hunting parties and served in auxiliary roles (Abbie, 1969; Meehan, 1977;
Carlson et al., 2007). Women were commonly seen flushing animals from bushy cover,
processing carcasses, and carrying killed game and broken hunting implements (Abbie,
1969; Meehan, 1977; Carlson et al., 2007).
This skeletal examination of the Roonka Flat sample serves as an example of
research that is vital for better understanding Australian prehistory. The use of foraging
models and direct measurements from load bearing post-cranial bones can provide
invaluable data to supplement archaeological and ethnographic evidence. Human beings
are subject to the environment, but also able to manipulate their surroundings through the
use of technology unlike other members of Animalia. None of these approaches can
adequately explain human behavior unilaterally, but a synthesis of these avenues of
research provides a rich picture of how prehistoric humans interacted with, and within,
their surrounding environment. The upcoming addition of cross-sectional dimensions will
63
Texas Tech University, Ethan C. Hill, May 2014
strengthen the interpretations made by this study, as well as extending analyses to other
facets of prehistoric life ways.
64
Texas Tech University, Ethan C. Hill, May 2014
CHAPTER V
CONCLUSION
The present data support both hypotheses concerning human mobility and sexual
division of labor for the Roonka Flat sample. External long bone dimensions suggest that
individuals living in the Murray River corridor during the post-ENSO period became
more mobile and developed increased sexual division of labor in response to deteriorating
and unstable climatic conditions.
These results validate the use of OFT to formulate testable hypotheses concerning
human behavior in archaeological contexts. If environmental contexts are well known,
especially over discreet time periods, then predictions can be made concerning human
behavior that can then be tested directly though skeletal data. OFT predicted that the
Roonka sample would exhibit increased mobility and sexual differentiation of behavior
based on climatic models and dietary remains from South Australia respectively. The
current evidence upheld both of these predictions, indicating that the use of encountercontingent prey choice, patch choice, and marginal value theorem can potentially provide
illuminating avenues of research into Australian prehistory.
While this study is in agreement with OFT predictions, the current data shed
doubt on an all-encompassing archaeological model of behavior change for prehistoric
South Australians. Neither model – risk minimization or intensification – was supported
or rejected in its entirety. Risk minimization’s prediction that Aboriginals became more
mobile in response to climatic degradation and instability was supported by femoral
circularity ratios and OFT predictions. While intensification’s claim of sedentary and
territorial populations is rejected by the current study, Lourandos’ (1983, 1985, 1997)
65
Texas Tech University, Ethan C. Hill, May 2014
assertion that males and females diversified their food procurement strategies to
incorporate a more diverse and stable diet set is buttressed. Although neither model was
entirely sufficient, it seems premature to reject either model. Since risk minimization and
intensification were formulated taking continent-wide archaeological patterns into
consideration, they may not be equipped to explain the regional trends of the Murray
River valley. Future research will integrate the results from this study with optimal
foraging theory and current archaeological evidence to form a more appropriate model
for Holocene human behavior in the Murray River valley of South Australia.
66
Texas Tech University, Ethan C. Hill, May 2014
BIBLIOGRAPHY
Abbie AA. 1951. 1951. The Australian Aborigine. Oceania 22: 99-100.
Abbie AA. 1969. The original Australians. London, Frederick Muller.
Attenbrow V. 2004. What’s changing: population size or land-use patterns? The
archaeology of Upper Mangrove Creek, Sydney Basin. Terra australis, Pandanus
Books. Canberra, Australian National University.
Auerbach BM, Ruff CB. 2006. Limb bone bilateral asymmetry: variability and
commonality among modern humans. Journal of Human Evolution 50: 203-218.
Balme J, Garbin G, Gould RA. 2001. Residue analysis and palaeodiet in arid Australia.
Australian Archaeology 53: 1-6.
Beveridge P. 1983. Of the Aborigines inhabiting the great lacustrine and riverine
depression of the Lower Murray, Lower Murrumbidgee, Lower Lachlan, and
Lower Darling. Journal and Proceedings of the Royal Society of New South
Wales 17: 19-74.
Bird DW, O’Connell JF. 2006. Behavioral ecology and archaeology. Journal of
Archaeological Research 14: 143-188.
Bird DW, Bliege Bird R, Codding BF. 2009. In pursuit of mobile prey: Martu hunting
strategies and archaeological interpretation. American Antiquity 74: 3-29.
Bliege Bird R. 1999. Cooperation and conflict: the behavioral ecology of the sexual
division of labor. Evolutionary Anthropology 8: 65-75
Bowdler S 1981. Hunters in the Highlands: Aboriginal Adaptations in the Eastern
Australian uplands. Archaeology in Oceania 16: 99-111.
Bridges PS. 1989. Changes in activities with the shift to agriculture in the Southeastern
United States. Current Anthropology 30: 385-394.
Bridges PS. 1995. Skeletal biology and behavior in ancient humans. Evolutionary
Anthropology: Issues, News, and Reviews 4: 112-120.
Bridges PS, Blitz JH, Solano MC. 2000. Changes in long bone diaphyseal strength with
horticulture intensification in West-Central Illinois. American Journal of Physical
Anthropology 112: 217-238.
Carlson KJ, Grine FE, Pearson OM. 2007. Robusticity and sexual dimorphism in the
postcranium of modern hunter-gatherers from Australia. American Journal of
Physical Anthropology 134: 9-23.
67
Texas Tech University, Ethan C. Hill, May 2014
Charnov EL. 1976. Optimal foraging: the marginal value theorem. Theoretical Population
Biology 9: 129-136.
Codding BF, Bliege Bird R. 2012. Should I stay or should I go now? the spatial dynamics
of foraging and diminishing returns. response to O’Connell and Allen (2012).
Australian Archaeology 74: 18-19.
Cole TM. 1994. Size and shape of the femur and tibia in northern Plains Indians. In:
Owsley DW, Jantz RL, editors. Skeletal Biology in the Great Plains: Migration,
Warfare, Health, and Subsistence. Washington, DC: Smithsonian Institution
Press. p 219-234.
David B. 1991. Raiders of the lost axe: on macropods, phalangers, where and why –
comments on Sutton’s comment of Morwood and Trezise (and Pleistocene axes).
Queensland Archaeological Research 8: 108-111.
David B. 2002. Landscapes, Rock-art and the Dreaming. An archaeology of
preunderstanding. Leicester, Leicester University Press.
David B, Lourandos H. 1998. Rock art and socio-demography in Northeast Australian
prehistory. World Archaeology 30: 193-219.
David B, Chant D. 1995. Rock art and regionalisation in North Queensland Prehistory,
Memoirs of the Queensland Museum 37. Brisbane, Queensland Museum.
Davidson DS. 1936. Australian throwing-sticks, throwing-clubs, and boomerangs.
American Anthropologist 38: 76-100.
Flood J. 1980. The Moth Hunters. Canberra, Australian Institute of Aboriginal Studies.
Flood J. 2001. Archaeology of the Dreamtime. Sydney, Collins.
Fresia A, Ruff CB, Larsen CS. 1990. Temoporal decline in bilateral asymmetry of the
upper limb on the Georgia coast. In: Larsen CS, editor. The Archaeology of
Mission Santa Catalina de Guale: 2. Biocultural Interpretations of a Population in
Transition. New York, Anthropological Papers of the American Museum of
Natural History, no. 68.
Frost HM. 1987. Bone “mass” and the “mechanostat”: a proposal. The Anatomical
Record 219: 1-9.
Frost HM. 1988. Vital biomechanics: proposed general concepts for skeletal adaptations
to mechanical usage. Calcified Tissue International 42: 145-156.
68
Texas Tech University, Ethan C. Hill, May 2014
Gagan MK, Hendy EJ, Haberle SG, Hantoro WS. 2003. Post-glacial evolution of the
Indo-Pacific Warm Pool and El Niño-Southern Oscillation. Quaternary
International 118: 127-143.
Gorecki P, Grant M, O’Connor S, Veth P. 1997. The morphology, function and antiquity
of Australian grinding implements. Archaeology in Oceania 32: 141-150.
Haapasalo H, Kontulainen S, Sievanen H, Kannus P, Jarvinen M, Vuori I. 2000.
Exercise-induced bone gain is due to enlargement in bone size without a change
in volumetric bone density: a peripheral quantitative computed tomography study
of the upper arms of male tennis players. Bone 27: 351-357.
Hawkes K, O’Connell JF, Blurton Jones NG. 1991. Hunting income patterns among the
Hadza: big game, common goods, foraging goals and the evolution of human diet.
Philosophical Transactions of the Royal Society of London 334B: 242-251.
Hawkes K, O’Connell JF, Blurton Jones NG. 1997. Hadza women’s time allocation,
offspring provisioning, and the evolution of post-menopausal lifespans. Current
Anthropology 38: 551-578.
Hiscock P. 1994. Technological responses to risk in Holocene Australia. Journal of
World Prehistory 8: 267-292.
Hiscock P. 2002. Pattern and context in the Holocene proliferation of backed artefacts in
Australia. In: Elston RG, Kuhn SL, editors. Thinking Small: Global Perspectives
on Microlithization. Arlington, VA, Archaeological Papers of the American
Anthropological Association (APA) 12. p 163-177.
Hiscock P. 2006. Blunt and to the point: changing technological strategies in Holocene
Australia. In: Lilley I, editor. Archaeology of Oceania: Australia and the Pacific
Islands. Oxford, Blackwell. p 69-95.
Hiscock P. 2008. Archaeology of Ancient Australia. New York, Routledge.
Hiscock P, Attenbrow V. 1998. Early Holocene backed artefacts from Australia.
Archaeology in Oceania 33: 49-63.
Hiscock P, Attenbrow V. 2004. A revised sequence of backed artefact production at
Capertee 3. Archaeology in Oceania 39: 94-99.
Holt BM. 2003. Mobility in Upper Paleolithic and Mesolithic Europe: evidence from the
lower limb. American Journal of Physical Anthropology 122: 200-215.
Hughes PJ, Lampert, RJ. 1982. Prehistoric population change in southern coastal
Australia. In: Bowdler S, editor. Coastal Archaeology in Eastern Australia.
Canberra, Australian National University. p 16-28.
69
Texas Tech University, Ethan C. Hill, May 2014
Ingman M, Gyllensten U. 2003. Mitochandrial genome variation and evolutionary history
of Australian and New Guinean Aborigines. Genome Research 13: 1600-1606
Kamminga J. 1980. A functional investigation of Australian microliths. Artefact 5: 1-18.
Kayser M, Brauer S, Weiss G, Schiefenhovel W, Underhill PA, Stoneking M. 2001.
Independent histories of human Y chromosomes from Melanesia and Australia.
American Journal of Human Genetics 68: 173-190.
Kennett DJ. 2005. The Island Chumash: Behavioral Ecology of a Maritime Society.
Berkeley, University of California Press.
Kennett DJ, Kennett JP. 2000. Competitive and cooperative responses to climatic
instability in southern California. American Antiquity 65: 379-395.
Kershaw AP. 1995. Environmental change in Greater Australia. Antiquity 69: 656-675.
Kontulainen S, Sievanen H, Kannus P, Pasanen M, Vuori I. 2002. Effect of long-term
impact-loading on mass size, and estimated strength of humerus and radius of
female racquet-sports players: a peripheral quantitative computed tomography
study between young and old starters and controls. Journal of Bone and Mineral
Research 17: 2281-2288.
Larsen CS. 1981. Functional implications of postcranial size reduction on the prehistoric
Georgia coast, USA. Journal of Human Evolution 10: 489-502.
Lieberman DE, Pearson OM. 2001. Trade-off between modeling and remodeling
responses to loading in the mammalian limb. Bulletin of the Museum of
Comparative Zoology 156: 269-282.
Littleton J, Allen H. 2007. Hunter-gatherer burials and the creation of persistent places in
southeastern Australia. Journal of Anthropological Archaeology 26: 283-298.
Lourandos H. 1983. Intensification: a late Pleistocene-Holocene archaeological sequence
from Southwestern Victoria. Archaeology in Oceania 18: 81-94.
Lourandos H. 1985. Intensification and Australian prehistory. In: Price TD, Brown JA,
editors. Prehistoric Hunter-gatherers: The Emergence of Cultural Complexity.
Orlando, Academic Press. p 385-423.
Lourandos H. 1997. Continent of Hunter-Gatherers: New Perspectives in Australian
Prehistory. Cambridge, Cambridge University Press.
Lovejoy CO, Trinkaus E. 1980. Strength and robusticity of the Neandertal tibia.
American Journal of Physical Anthropology 53:465-470.
70
Texas Tech University, Ethan C. Hill, May 2014
Lovejoy CO, Burstein AH, Heiple KG. 1976. The biomechanical analysis of bone
strength: a method and its application to platycnemia. American Journal of
Physical Anthropology 44: 489-506.
Lovejoy CO, McCollum MA, Reno PL, Rosenman BA. 2003. Developmental biology
and human evolution. Annual Review of Anthropology 32: 85-109.
MacArthur RH, Pianka ER. 1966. On the optimal use of a patchy environment. American
Naturalist 100.
Maggiano IS, Schultz M, Kierdorf H, Sosa TS, Maggiano CM, Blos VT. 2008. Crosssectional analysis of long bones, occupational activities and long-distance trade of
the classic Maya from Xcambó – archaeological and osteological evidence.
American Journal of Physical Anthropology 136: 470-477.
Marchi D. 2008. Relationships between lower limb cross-sectional geometry and
mobility: the case of a Neolithic sample from Italy. American Journal of Physical
Anthropology 137: 188-200.
Markgraf V, Dodson JR, Kershaw AP, McGlone MS, Nicholls N. 1992. Evolution of late
Pleistocene and Holocene climates in the circum-South Pacific land areas.
Climate Dynamics 6: 193-211.
Marsh RL, Ellerby DJ, Carr JA, Henry HT, Buchanan CI. Partitioning the energetics of
walking and running: swinging the limbs is expensive. Science 303: 80-83.
McDonald JJ, Rich E, Barton H. 1994. The Rouse Hill Infrastructure Project (Stage 1) on
the Cumberland Plain, western Sydney. In: Sullivan ME, Brockwell S, Webb A,
editors. Archaeology in the North: Proceedings of the 1993 Australian
Archaeology Association Conference. Darwin, Australian National University.
p 259-293.
McDonald JJ, Donlon D, Field JH, Fullagar RLK, Coltrain JB, Mitchell P, Rawson M.
2007. The first archaeological evidence for death by spearing in Australia.
Antiquity 81: 877-885.
Meehan B. 1977. Man does not live by calories alone: the role of shellfish in a coastal
cuisine. In: Allen J, Golson J, Jones R, editors. Sunda and Sahul: prehistoric
studies in Southeast Asia, Melanesia, and Australia. New York, Academic Press.
p 493-531.
Morwood MJ. 1987. The archaeology of social complexity in south-east Queensland.
Proceedings of the Prehistoric Society 53: 337-350.
71
Texas Tech University, Ethan C. Hill, May 2014
Mulvaney DJ, Kamminga J. 1999. Prehistory of Australia. Washington, Smithsonian
Institution Press.
Nikander R, Sievanen H, Uusi-Rasi K, Heinon A, Kannus P. 2006. Loading modalities
and bone structure at nonweight-bearing upper extremity and weight-bearing
lower extremity: a pQCT study of adult female athletes. Bone 39: 886-894.
O’Connell JF, Allen J. 2012. The restaurant at the end of the universe: modelling the
colonisation of Sahul. Australian Archaeology 74: 5-17.
Pardoe C. 1988. The cemetery as symbol: the distribution of prehistoric Aboriginal burial
grounds in southeastern Australia. Archaeology in Oceania 23: 1-16.
Pate FD. 1998a. Bone collagen stable nitrogen and carbon isotopes as indicators of past
human diet and landscape use in southeastern South Australia. Australian
Archaeology 46: 23-29.
Pate FD. 1998b. Stable carbon and nitrogen isotope evidence for prehistoric huntergatherer diet in the lower Murray River Basin, South Australia. Archaeology in
Oceania 33: 92-99.
Pate FD. 2000. Bone chemistry and palaeodiet: Bioarchaeological research at Roonka
Flat, Lower Murray River, South Australia 1983 – 1999. Australian Archaeology
50: 67-74.
Pate FD. 2006. Hunter-gatherer social complexity at Roonka Flat, South Australia. In:
David B, Barker B, McNiven IJ, editors. The Social Archaeology of Australian
Indigenous Societies. Canberra, Aboriginal Studies Press. p 226-241.
Pearson OM. 2000. Activity, climate, and postcranial robusticity: implications for
modern human origins and scenarios of adaptive change. Current Anthropology
41: 569-607.
Pretty GL 1977. The cultural chronology of Roonka Flat. In: Wright RVS, editor. Stone
Tools as Cultural Markers: Change, evolution and complexity. Canberra,
Australian Institute of Aboriginal Studies. p 288-331.
Pretty GL. 1986. The prehistory of South Australia. In: Richards E, editor. The Flinders
History of South Australia. Adelaide, Wakefield Press. p 33-62.
Pretty GL. 1988. Radiometric chronology and significance of the fossil hominid sequence
from Roonka, South Australia. In: Prescott JR, editor. Early Man in the Southern
Hemisphere (Supplement to Archaeometry: Australasian Studies) 1988. p 32-52.
Pretty GL, Kricun ME. 1989. Prehistoric health status of the Roonka population. World
Archaeology 21: 198-224.
72
Texas Tech University, Ethan C. Hill, May 2014
Prokopec M. 1979. Demographical and morphological aspects of the Roonka
populations. Archaeology and Physical Anthropology in Oceania 14: 11-26.
Raab LM, Larson DO. 1997. Medieval climatic anomaly and punctuated cultural
evolution in coastal southern California. American Antiquity 63: 319-336.
Robertson G. 2005. Backed artefact use in Eastern Australia: a residue and use-wear
analysis. Ph. D. dissertation, University of Queensland-Brisbane.
Rockhold LA. 1998. Secular change in external femoral measures form 1840 to 1970: a
biomechanical interpretation. M.A. thesis, University of Tennessee-Knoxville.
Ruff CB. 1987. Sexual dimorphism in human lower limb bone structure: relationship to
subsistence strategy and sexual division of labor. Journal of Human Evolution
16: 391-416.
Ruff CB. 1994. Biomechanical analysis of northern and southern Plains femora:
behavioral implications. In: Owsley DW, Jantz RL, editors. Skeletal Biology in
the Great Plains: Migration, Warfare, Heath, and Subsistence. Washington, DC:
Smithsonian Institution Press. p 235-246.
Ruff CB. 2000. Biomechanical analyses of archaeological human skeletons. In:
Katzenburg MA, Saunders SR, editors. Biological Anthropology of the Human
Skeleton. New York, Alan R Liss. p 71-102.
Ruff CB. 2002. Long bone articular and diaphyseal structure in Old World monkeys and
apes, I: locomotor effects. American Journal of Physical Anthropology
119: 305-342.
Ruff CB, Hayes WC. 1983a. Cross-sectional geometry of Pecos Pueblo femora and tibiae
– a biomechanical investigation: I. Method and general patterns of variation.
American Journal of Physical Anthropology 60: 359-382.
Ruff CB, Hayes WC. 1983b Cross-sectional geometry of Pecos Pueblo femora and tibiae
– a biomechanical investigation: II. Sex, age, and side differences. American
Journal of Physical Anthropology 60: 383-400.
Ruff CB, Larsen CS, Hayes WC. 1984. Structural changes in the femur with the
transition to agriculture on the Georgia Coast. American Journal of Physical
Anthropology 64: 125-136.
Ruff CB, Trinkaus E, Holliday TW. 1997. Body mass and encephalization in Pleistocene
Homo. Nature 387: 173-176.
73
Texas Tech University, Ethan C. Hill, May 2014
Ruff CB, Holt BM, Trinkaus E. 2006. Who’s afraid of the big bad Wolff?: “Wolff’s
Law” and bone functional adaptation. American Journal of Physical
Anthropology 129: 484-498.
Shaw CN, Stock JT. 2009. Habitual throwing and swimming correspond with upper limb
diaphyseal strength and shape in modern human athletes. American Journal of
Physical Anthropology 140: 160-172.
Shulmeister J, Lees BG. 1995. Pollen evidence from tropical Australia for the onset of an
ENSO-dominated climate at c. 4000 B.P. The Holocene 5: 10-18.
Sih A, Christensen B. 2001. Optimal diet theory: when does it work, and when and why
does it fail? Animal Behavior 61: 379-390.
Singh G, Luly J. 1991. Changes in vegetation and seasonal climate since the last full
glacial at Lake Frome, South Australia. Palaeogeography, Palaeoclimatology,
Palaeoecology. 84: 75-86.
Slack MJ, Fullagar RLK, Field J, Border A. 2004. New Pleistocene ages for backed
artefact technology in Australia. Archaeology in Oceania 39: 131-137.
Sládek V, Berner M, Sosna D, Sailder R. 2007. Human manipulative behavior in the
central European late eneolithic and early bronze age: humeral bilateral
asymmetry. American Journal of Physical Anthropology 133: 669-681.
Smith MA. 1978. A note on the fauna from Devon Downs shelter. Australian
Archaeology 8: 19-21.
Smith MA 1982. Devon Downs reconsidered: changes in site use at a lower Murray
Valley rockshelter. Archaeology in Oceania 17: 109-116.
Smith P, Prokopec M, Pretty G. 1988. Dentition of a Prehistoric Population from Roonka
Flat, South Australia. Archaeology in Oceania 23: 31-36.
Sparacello VS, Marchi D. 2008. Mobility and subsistence economy: a diachronic
comparison between two groups settled in the same geographical area (Liguria,
Italy). American Journal of Physical Anthropology 136: 485-495.
Stephens DW, Brown JS, Ydenberg RC. 2007. Foraging Behavior and Ecology. Chicago,
University of Chicago Press.
Stiner MC, Munro N, Surovell T. 2000. The tortoise and the hare: small-game use, the
broad spectrum revolution, and Paleolithic demography. Current Anthropology
41: 39-74.
74
Texas Tech University, Ethan C. Hill, May 2014
Stock JT. 2006. Hunter-gatherer postcranial robusticity relative to patterns of mobility,
climatic adaptation, and selection for tissue economy. American Journal of
Physical Anthropology131: 194-204.
Stock JT, Pfeiffer SK. 2001. Linking structural variability in long bone diaphyses to
habitual behaviors: foragers from the southern African Later Stone Age and the
Andaman Islands. American Journal of Physical Anthropology 115: 337-348.
Stock JT, Pfeiffer SK. 2004. Long bone robusticity and subsistence behavior among
Later Stone Age foragers of the forest and fynbos biomes of South Africa. Journal
of Archaeological Sciences 31: 999-1013.
Stock JT, Shaw CN. 2007. Which measures of diaphyseal robusticity are robust? A
comparison of external methods of quantifying the strength of long bone
diaphyses to cross-sectional geometric properties. American Journal of Physical
Anthropology 134: 412-423.
Tonkinson R. 1978. The Mardudjara aborigines – living the dream in Australia’s desert.
Fort Worth TX, Holt, Rinehart, and Winston, Inc.
Trinkaus E, Ruff CB. 1999a. Diaphyseal cross-sectional geometry of Near Eastern
Middle Palaeolithic Humans: the femur. Journal of Archaeological Science
26: 409-424.
Trinkaus E, Ruff CB. 1999b. Diaphyseal cross-sectional geometry of Near Eastern
Middle Palaeolithic Humans: the tibia. Journal of Archaeological Science
26: 1289-1300.
Trinkaus E, Churchill SE, Ruff CB. 1994. Postcranial robusticity in Homo, II: humeral
bilateral asymmetry and bone plasticity. American Journal of Physical
Anthropology 93: 1-34.
Tudhope AW, Chilcott CP, McCulloch MT, Cook ER, Chappell J, Ellam RM, Lea DW,
Lough JM, Shimmield GB. 2001. Variability in the El Niño-Southern Oscillation
through a Glacial-Interglacial Cycle. Science 291: 1511-1517.
Turney CSM, Hobbs D. 2006. ENSO influence on Holocene Aboriginal populations in
Queensland, Australia. Journal of Archaeological Science 33: 1744-1748.
Veitch B. 1999. Shell middens on the Mitchell Plateau: a reflection of a wider
phenomenon? In: Hall J, McNiven IJ, editors. Australian Coastal Archaeology.
Canberra: ANH Publications, Australian National University. p 51-64.
Veth P, O’Connor S. 1996. A preliminary analysis of basal grindstones from the
Carnarvon Range, Little Sandy Desert. Australian Archaeology 43: 20-22.
75
Texas Tech University, Ethan C. Hill, May 2014
Veth P, Hiscock P, Williams A. 2011. Are tulas and ENSO linked in Australia?.
Australian Archaeology 72: 7-14.
Waguespack NM. 2005. The organization of male and female labor in foraging societies:
implications for early Paleoindian archaeology. American Anthropologist
107: 666-676.
Weiss E. 2009. Sex differences in humeral bilateral asymmetry in two hunter-gatherer
populations: California Amerinds and British Columbian Amerinds. American
Journal of Physical Anthropology 140: 19-24.
Wescott DJ. 2001. Structural variation in the humerus and femur in the American Great
Plains and adjacent regions: differences in subsistence strategy and physical
terrain. Ph. D. dissertation, University of Tennessee-Knoxville.
Wescott DJ. 2006. Effect of mobility on femur midshaft external shape and robusticity.
American Journal of Physical Anthropology 130: 201-213.
Wescott DJ, Cunningham DL. 2006. Temporal changes in Arikara humeral and femoral
cross-sectional geometry associated with horticultural intensification. Journal of
Archaeological Science 33: 1022-1036.
White TD, Black MT, Folkens PA. 2012. Human Osteology (3rd edition). Academic
Press.
Woodroffe CD. 2000. Deltaic and estuarine environments and their Late Quaternary
dynamics on the Sunda and Sahul shelves. Journal of Asian Earth Sciences.
18: 393-413.
Websites
Australian Government: Bureau of Meteorology. http://www.bom.g
76
Texas Tech University, Ethan C. Hill, May 2014
APPENDIX A
EXTERNAL DIAPHYSEAL MEASUREMENTS
TABLE A.1. Femoral external diaphyseal data by individual
Males
Pre-ENSO
Females
Post-ENSO
Males
AP/ML1
AP diameter
ML diameter
Circum.
A16
1.12
28
25
85
A37
1.04
28
27
87
A51
1.04
29
28
89
A61
1.22
30
24.5
87
A63
1.19
32
27
95
A64
0.98
20.5
21
66
A89
1.16
33.5
29
95
A91
1.13
30.5
27
90
A104
0.96
26
27
83
A1072
0.92
23
25
78
A108
1.21
28.5
23.5
86
A7
1.00
23.2
23.1
75
A13a
1.04
27
26
85
2
A36
0.98
23.5
24
74
A38
1.05
23
22
72
A66
1.00
22.5
22.5
71
A78
0.98
24
24.5
77
A1
1.25
33.1
26.4
92
A42
1.18
28.8
24.4
84
A5a
1.10
30.4
27.7
95
A12a
1.08
27
25
82
A20
1.08
27
25
83
A21a
1.23
27
22
80
A23
1.19
32
27
94
A29
1.28
30
23.5
84
A30
0.96
27
28
91
A34
1.00
23
23
75
A45
1.04
26.5
25.5
84
A50
1.09
30.5
28
94
A56
1.19
28.5
24
85
A80
1.13
27
24
85
A85
1.22
30
24.5
86
A90
1.31
32
24.5
89
A92
1.13
29.5
26
87
A94
1.14
32
28
96
77
Texas Tech University, Ethan C. Hill, May 2014
Females
A13
1.04
27
26
85
A14
1.08
27
25
82
A28
1.00
23
23
75
A30a
1.14
24
21
72
A31
1.24
28.5
23
83
A32
1.16
29
25
85
A32a
1.00
23
23
74
A55
1.05
23
22
74
A75
1.23
24.5
20
71
A87
1.07
22.5
21
72
A96
1.00
24
24
76
1
AP/ML = midshaft circularity index, AP diameter = midshaft anteroposterior diameter, ML
diameter = midshaft mediolateral diameter, Circum. = midshaft circumference
2
Right side measurements substituted for left side
TABLE A.2. Tibial external diaphyseal data by individual
Males
Pre-ENSO
Females
Mid AP/ML1
NF AP/ML
AP
diameter
ML
diameter
Circum.
A16
1.45
1.55
29
20
78
A37
1.46
1.57
35
24
90
A51
1.35
1.58
31
23
86
A61
1.27
1.40
28
22
87
A91
1.62
1.65
31.5
19.5
83
A105
1.38
23.5
17
69
A107
1.49
1.58
26
17.5
71
A108
1.63
1.56
31
19
82
A7
1.37
1.57
23.5
17.1
72
A13a
1.37
1.70
26
19
73
A36
1.72
A38
1.38
1.43
23.5
18
70
A66
1.21
1.44
23
19
69
A78
1.37
1.53
26
19
78
78
Texas Tech University, Ethan C. Hill, May 2014
Males
A12
1.21
1.51
27.8
22.9
89
A4
1.53
1.45
25.6
16.7
69
A5a
1.50
1.48
34
22.6
84
A12a
1.29
1.68
27
21
80
A15
1.32
1.45
25
19
75
A20
1.33
1.84
28
21
80
A21a
1.24
26
21
80
A23
1.52
1.44
35
23
97
A29
1.53
1.57
29
19
77
A30
1.12
1.37
28
25
85
A34
1.93
1.50
28
14.5
70
A45
1.50
1.57
30
20
85
1.36
1.59
30
22
85
1.32
1.50
29
22
91
A83
1.36
1.75
28.5
21
81
A85
1.38
1.53
29
21
84
29
21
85
34.5
23
93
A50
A80
PostENSO
2
A90
Females
1.73
A92
1.38
1.66
A94
1.50
A13
1.37
1.70
26
19
73
A14
1.30
1.43
26
20
73
A28
1.61
1.74
29
18
78
A30a
1.33
1.30
26
19.5
73
A31
1.17
1.30
24.5
21
76
A32a
1.22
1.50
22
18
68
A55
1.31
1.58
23
17.5
72
A75
1.22
1.38
22
18
69
A87
1.29
1.42
22.5
17.5
69
A96
1.25
1.38
25
20
76
1
Mid AP/ML = midshaft circularity index, NF AP/ML = circularity index taken at nutrient
foramen, AP diameter = midshaft anteroposterior diameter, Circum. = midshaft circumference
2
Right side measurements substituted for left side
79
Texas Tech University, Ethan C. Hill, May 2014
TABLE A.3. Humeral bilateral asymmetry data by individual
Males
Pre-ENSO
Females
Males
Post-ENSO
Females
Circum. asym.1
Max dia. asym.
Min. dia. asym.
A37
90.91
91.30
91.67
A61
93.75
91.11
96.77
A63
95.65
87.76
94.59
A64
97.78
100.00
100.00
A89
93.06
88.00
92.11
A104
98.28
95.00
100.00
A105
102.13
100.00
104.17
A107
98.18
97.37
103.57
A108
96.97
97.87
97.06
A7
94.34
91.89
96.15
A13a
98.21
100.00
96.43
A36
100.00
94.12
104.35
A38
101.82
95.00
100.00
A78
96.43
94.87
96.55
A1
89.86
87.50
94.12
A4
96.23
97.14
96.55
A12a
96.77
97.62
100.00
A18
93.94
97.73
88.57
A21a
91.53
90.00
93.75
A23
93.94
86.67
100.00
A29
91.80
92.86
87.88
A45
93.85
86.96
100.00
A50
95.65
89.80
91.67
A56
95.31
93.18
91.67
A80
93.15
90.20
95.24
A85
98.46
95.65
94.12
A90
98.44
95.56
94.12
A92
93.85
95.45
97.06
A13
98.21
100.00
96.43
A14
98.33
100.00
90.32
A28
94.83
92.31
100.00
A31
96.55
100.00
100.00
A32a
101.92
94.74
90.00
A55
96.43
102.56
100.00
A75
100.00
102.70
96.30
A87
98.04
97.14
100.00
A96
100.00
100.00
96.55
1
Circum. asym. = midshaft circumference asymmetry, Max dia. asym. = midshaft maximum
diameter asymmetry, Min dia. asym. = midshaft minimum diameter asymmetry
80
Texas Tech University, Ethan C. Hill, May 2014
TABLE A.4. Ulnar bilateral asymmetry data by individual
AP dia. asym.1
Males
Pre-ENSO
Females
Males
Post-ENSO
ML dia. asym.
Neck asym.
94.29
A37
85.71
88.24
A51
93.33
100.00
A61
100.00
79.41
A63
93.75
96.43
A64
95.00
90.91
A89
96.77
93.75
A91
96.43
106.90
A105
95.00
92.00
A108
88.46
88.57
A109
96.30
103.13
A7
95.00
85.71
A38
100.00
89.29
A78
100.00
92.59
A1
105.47
100.69
A5a
102.03
93.92
A21a
100.00
78.57
A23
100.00
94.44
A29
92.31
90.32
A30
106.25
93.75
97.37
A34
92.31
100.00
106.25
A50
93.55
100.00
73.91
A56
103.57
87.10
94.74
A80
86.84
90.32
97.14
A85
103.70
93.75
102.86
A90
119.05
96.67
A92
104.17
96.55
105.56
A14
91.67
107.14
103.23
A28
A31
Females
96.30
102.50
93.75
97.30
90.00
100.00
100.00
A32a
92.31
100.00
A55
110.00
85.71
A87
104.35
103.85
A96
104.00
100.00
1
100.00
100.00
AP dia. asym. = midshaft anteroposterior diameter asymmetry, ML dia. asym. = midshaft
mediolateral diameter asymmetry, Neck asym. = neck circumference asymmetry
81
Texas Tech University, Ethan C. Hill, May 2014
TABLE A.5. Radial bilateral asymmetry data by individual
Males
Pre-ENSO
Circ. asym.1
AP dia. asym.
ML dia. asym.
A37
93.48
84.62
93.55
A61
88.64
88.00
87.10
A63
102.27
100.00
96.43
A64
100.00
94.12
100.00
A91
95.45
104.00
100.00
A108
102.17
100.00
88.24
104.76
103.85
A109
Female
Males
Post-ENSO
Females
A7
97.22
89.81
106.78
A13a
97.30
90.91
92.31
A36
100.00
100.00
100.00
A38
94.74
100.00
100.00
A78
97.30
86.96
95.83
A1
97.73
86.67
93.67
A4
100.00
100.00
102.70
A21a
97.56
91.67
100.00
A23
104.55
108.33
107.14
A29
100.00
91.67
89.66
A50
107.32
96.15
100.00
A56
100.00
100.00
103.33
A80
95.74
89.29
96.77
A85
100.00
92.59
100.00
A90
97.62
100.00
90.00
A13
97.30
90.91
92.31
A14
100.00
91.67
93.33
A28
100.00
100.00
92.86
A32a
94.87
90.91
92.31
A55
85.37
90.91
96.30
A96
100.00
95.65
100.00
1
Circum. asym. = midshaft circumference asymmetry, AP dia. asym. = midshaft anteroposterior
diameter asymmetry, ML dia. asym. = midshaft mediolateral diameter asymmetry
82