Journal of World Prehistoty, Vol. 10, No. 2, 1996
Human Biology in the Classic Maya Collapse:
Evidence from Paleopathology and Paleodiet
Lori E. Wright 1,3 and Christine D. White 2
We review evidence from human biology--paleopathological and isotopic
paleodietary studies on ancient Maya skeletons--to assess the validity of
ecological models of the Classic Maya collapse, in which elevated disease and
deteriorating diet are commonly assumed. To be upheld, the health arguments
of ecological models require that the Maya disease burden (1) was greater
than that for many other societies and (2) increased over the span of
occupation. The dietary argument requires (1) consistent change in diet from
Preclassic and Early Classic Periods to the Terminal Classic and (2) increasing
social divergence in diet. A correlation between diet and disease is necessary
to link these arguments. Neither pathology nor isotopic data consistently
support these criteria. Instead, it appears that local environmental and political
factors created diversity in both disease burden and diet. In view of the human
biological data, we are skeptical of ecological models as generalized
explanations for the abandonment of Classic Maya sites in the southern
lowlands.
KEY WORDS: Maya collapse; palcodiet; paleopathology; stable isotopes.
INTRODUCTION
The rise and demise of complex society in tropical regions have been
a recurrent focus of anthropological fascination. To Western scholarship,
tropical forest cities have historically been shrouded in mystery behind
1Department of Geology, McMaster University, Hamilton, Ontario L8S 4M1, Canada.
2Department of Anthropology, University of Western Ontario, London, Ontario N6A 5C2,
Canada.
a'I'o whom correspondence should be addressed. After August 1996: Department of
Anthropology, Texas A&M University, College Station, Texas 77843-4352.
147
0892-7537/96/0600-0147509.50/09 1996Henum Publishing Corporation
148
Wright and White
fronds of encroaching vegetation. Hence the ancient Maya civilization of
Central America is often characterized as curious, in both popular and
scholarly works, and viewed as an ecological anomaly of high culture that
developed in a tropical backwater despite all odds. This mystique is reinforced by the collapse of many large Maya cities in the southern part of
the lowlands, centuries prior to the arrival of the Spanish in the New World.
The fate of the Late Classic populace has been a central issue in Maya
studies since the first explorations of abandoned temples in the nineteenth
century. Although recent work is beginning to emphasize the role of sociopolitical turmoil (Demarest, 1992; 1993; Fash, 1994; Miller, 1993; Suhler
and Freidel, 1992), ecological considerations in this demographic transition
remain of paramount importance for many scholars (Culbert, 1988; Santley
et al., 1986; Webster et al., 1992).
Ancient Maya civilization flourished in lowland Guatemala, Mexico,
Belize, and Honduras from about 900 BC to AD 900. Settlement studies
indicate that population density increased substantially over the Classic Period, AD 50-900 (Ashmore, 1981; Culbert and Rice, 1990). Supported by
a complex agricultural system, Classic Maya cities were home to a diverse
population of farmers, traders, artisans, and religious specialists. Many sites
in the south central Maya area (especially the Guatemalan Pet6n and Belize) were abandoned near the end of the first millenium AD (Culbert,
1973). In the humid southern lowlands only a few communities persisted
near the central Pet6n lakes (D. Rice, 1986; P. Rice, 1986; Rice and Rice,
1984), but cities continued to flourish in the dry northern lowlands of Yucatan and in the Maya Highlands of Chiapas and Guatemala during Postclassic and Colonial tim.es.
A prevalent group of models invokes increasing population density
over the span of the Classic Period and environmental degradation attendant with overpopulation as an ultimate cause of the collapse of Late Classic polities (Culbert, 1988; Santley et al., 1986; Webster et al., 1992; Willey
and Shimkin, 1973). The reasoning behind this argument is as follows. In
tropical forests, the bulk of nutrients is held in biomass rather than stored
in the soils, as they are in temperate regions. Thus, when the forest is cut
for swidden or "milpa" agriculture, nutrients are rapidly exhausted and the
soils are prone to erosion from heavy tropical rains. Under conditions of
population growth, milpa farming becomes extensive and expansive. The
expansive cycle of Maya agriculture is argued to have reached a critical
point in the Late Classic Period, where production could not keep pace
with increasing consumer demands due to the degradation of agricultural
fields from overuse and erosion. Under pressure to produce sufficient food,
farmers are argued to have responded by cultivating more high-yield crops,
especially maize. Together with heavy predation of wild faunal populations,
Human Biology in the Classic Maya Collapse
149
agricultural stress would have resulted in a gradual deterioration of both
dietary quality and quantity. In turn, nutritional stress compounded other
health problems, especially infectious disease. In synergism, malnutrition
and infection took their toll on the demographic structure of the population, elevating both childhood and adult mortality and precipitating a
demographic collapse (Santley et al., 1986; Santley, 1990). In short, Classic
Lowland Maya civilization was defeated by environmental limitations. Biological data gleaned from human skeletons played a significant role in the
development and tenacity of such "ecological" explanations for the collapse
in Maya scholarship.
With recent advances in the decipherment of hieroglyphics, we now
have a better understanding of the political history of individual Maya citystates, and the role of the charismatic power and prestige of the ruler in
local and interregional interaction (Culbert, 1991; Demarest, 1992; Freidel,
1986). These new data are also contributing to a better understanding of
the role of interpolity conflict in the collapse of individual city-states in some
regions (Demarest, 1993; Fash, 1994). Ongoing excavations highlight the extremely variable occupation histories of neighboring sites even within regions
(Demarest and Houston, 1989, 1990; Demarest et al., 1991, 1992; Vald6s et
aL, 1993). This is in marked contrast to earlier models of the collapse that
tended toward regional or pan-lowland generalizations and from whence
arose the generalized "ecological" scenario sketched out above (Culbert,
1973). Newly armed with this political information, recent scholarship highlights the ninth century AD as one marked episode in a series of periodic
florescences and collapses (Fash, 1994; Marcus, 1995; Demarest, 1992).
Despite this new intraregional and political focus, considerations of
the collapse often retain an environmental element, in support of which
human biological data may be cited (e.g., Webster et al., 1992). This tendency is rooted in a common assumption that bioarchaeological studies
have documented the deterioration of diet and health over the span of the
Classic Period. Summarizing this perception, Sharer (1994, p. 344) states,
That the ancient Maya were vulnerable to epidemic disease is indicated by skeletal
studies at Tikal, Altar de Sacrificios, and Copan. These studies demonstrate
progressive nutritional deficiencies and increasing disease potentials in lowland
populations toward the end of the Classic period, owing probably to food shortages,
crowding, and overpopulation.
In this paper, we review the biological data and recent research on Maya
paleodiet and find that this conclusion might be premature.
Ecological explanations for the collapse are buttressed by the observation that traditional peoples living in today's tropical forests have low
population density and typically use extensive agricultural methods--a
natural outcome of limited available analogies. For example, (1) there are
150
Wright and White
no surviving indigenous complex civilizations in tropical forest environments to use for comparison. Although a number of complex societies arose
in such habitats around the world, most had collapsed prior to the integration of world systems which began in the sixteenth century. Moreover,
(2) modem Western culture is derived from early civilizations which developed in temperate environments. Finally, (3) tropical rain forests remain
one of the last frontiers of agrotechnological development today.
This ecological model took hold during the 1960s, when large-scale
settlement studies began to reveal an apparent contradiction between the
ubiquity of settlement remains (and the high population density implied
by them) and the extensive swidden agricultural system employed by modern Peteneros. As this contradiction became apparent, it set off a flurry of
research into subsistence alternatives that might have fed the burgeoning
Classic populace (Harrison and Turner, 1978). Evidence came to light that
agricultural terraces were constructed to combat soil erosion and wetland
areas were drained for intensive horticulture (Siemens and Puleston, 1972;
Turner, 1974). These intensive agrosystems would have been much more
sustainable than swidden. While this work might have alleviated concerns
about environmental limitations on Maya cultural elaboration, agricultural
intensification was often taken as evidence for unsuccessful adaptation to
environmental pressure (Adams, 1983; Culbert, 1988), and the failure of
these intensive systems is cited as a trigger for the collapse (Harrison, 1977;
Healy et al., 1983). Although wetland agriculture was not as widespread as
once proposed, and some densely populated areas were not serviced by its
high productivity (Adams et at, 1990; Dunning and Beach, 1994; Pope and
Dahlin, 1989), a variety of soil management strategies was adapted to local
conditions that may have permitted sustained cultivation (Dunning and
Beach, 1994; Fedick and Ford, 1990). Although the magnitude of population growth over the Classic Period was dramatic, the notion that agricultural systems were stretched beyond capacity is now being questioned
(Turner, 1990).
It was reasonable to assume that modem Petrn milpa agriculture ought
to have been an appropriate analogy for the interpretation of prehistoric
agrosystems, but it now appears that our understanding of modem agriculture was inadequate to appreciate the subtleties of indigenous Petrn agroforestry. Research with the Itz~ and the Lacandon Maya suggests that more
complex forest management strategies and cropping systems may have been
fundamental to prehistoric agronomy (Arran, 1993; Barrera et aL, 1977;
Nations and Nigh, 1980). This indigenous agroforestry system mimics the
diversity of the rain forest and preserves soil cover, a stark contrast to the
essentially Ladino milpa system. It should also be noted that Petrn farming
systems were dramatically changed by the Spanish colonial structure, which
Human Biology in the Classic Maya
Collapse
151
placed heavy demands on local farmers to produce surplus maize, and discouraged the cultivation of foods other than storable grains (Schwartz,
1990, p. 62; Atran, 1993, pp. 640, 676). Instead, prehistoric Maya agriculture
was probably based on "fixed plot variable fallow farming," a land-use strategy emphasizing intensive ongoing use of spatially discontinuous permanent
fields through various stages of cultivation (McAnany, 1995; Fash, 1994).
Although the Classic landscape was clearly a culturally modified environment (Rice, 1993), it did not likely emphasize extensive maize monocrop
agriculture as once envisioned. Moreover, the occurrence of faunal remains
of forest species such as tapir, jaguar, and monkeys implies the maintenance
of some primary forest refugia (Pohl, 1990; Emery, 1991).
The argument that environmental degradation lay behind the demographic decline gained strong support from sedimentology and palynological studies of lake cores from Central Pet6n (Deevey et al., 1979; Rice and
Rice, 1984). These document substantial erosion over time due to human
intervention and forest clearance. The pollen data show the replacement
of forest trees with maize, cultigens, and successional species during the
peak occupation. A brief increase in maize pollen during the final years
of Maya occupation, interpreted as a last-ditch attempt to produce enough
food to feed a starving populace, is followed by a dramatic resurgence of
forest tree pollen (Wiseman, 1985). In the original analysis, this forest rebound was assumed to correspond to the collapse, but recent paleolimnological work southwest of Lake Pet6n Itz~i indicates that forest regrowth
did not occur until the mid seventeenth century (Brenner et al., 1990). Although considerable spatial and chronological variability in reforestation
might be expected after the collapse, these data imply a primarily agricultural landscape for the lake region until the Spanish reducciones of the
early 1700s (Rice and Rice, 1994; personal commmunication, 1995). These
data call into question the precipitous nature of environmental disaster in
the Terminal Classic Central Pet6n. Likewise, the extent of depopulation
may have been less complete than often assumed. As with many Late Classic residences that are missed by surface survey (Johnston, 1994), many
Postclassic and Colonial structures may have been archaeologically invisible
(Jones, 1989). As Fash notes (1994, p. 188), fairly large and organized populations may well have persisted long after the collapse.
A key element of ecological models is the argument that maize-based
diets are unable to meet nutritional requirements. For instance, Saul (1972,
1973) and Santley et al. (1986) argue that Maya diets were deficient in
iron, niacin, and the amino acids tryptophan, lysine, and methionine and
imply that the entire population was malnourished. However, the nutritional drawbacks of raw maize are alleviated by consuming complementary
foods, such as beans, which are high in tryptophan and help to complete
152
Wright and White
the protein, and by processing maize with alkali, which significantly improves the balance of amino acids, makes more niacin available, and adds
calcium (Bressani et al., 1958; Bressani and Scrimshaw, 1958; Katz et al.,
1974). Diets with a substantial component of processed maize with beans
are generally sufficient to meet the protein needs for adults but may be
inadequate for the higher metabolic demands of children, and cannot supply them with sufficient iron. But behavioral factors also play a role in
subadult undernutrition. Children often suffer from appetite loss due to
intestinal and respiratory infection, so simply do not eat enough to supply
nutrient demands even when adequate food is available (Beh~ir, 1977; Mata
and Salas, 1984). It is important to note that the bulk of skeletal evidence
for nutritional pathology relates to health status during growth and development, measuring the health of children, not adults.
Early speculations on the collapse did include epidemic disease (Spinden, 1928), but the proposition that nutritional disease could have played
a role in the collapse was first raised by Hooton (1940) with skeletal data.
The nutritional hypothesis gained prominent support because of two
osteological reports: Haviland's (1967) study of stature at Tikal, which suggested a decline in health over the span of the Classic Period, and Saul's
(1972) detailed monograph on Maya osteology at Altar de Sacrificios. Both
works were landmarks in the emerging field of bioarchaeology, demonstrating the richness of data that could be gleaned from human skeletal remains.
They provided skeletal indications that health may have been compromised
among Classic Maya populations and hypothesized that health burdens may
have changed over time. It is important to recall that comparative paleopathological data from other cultures were very limited at this time, so
Maya disease burdens could not be evaluated in a wider context. Although
Saul (1972) hesitated to attribute depopulation directly to disease and malnutrition, he argued that the lowland Maya teetered on an unhealthy precipice, prone to collapse. Archaeologists have generally not heeded his
caution, and assert that the osteological data provide evidence of "starvation" (Ix)we, 1985, p. 92; see also Tainter, 1988, p. 174). Yet few, if any,
osteologists would claim an ability to diagnose "starvation" per se from
skeletal remains.
The malnutrition hypothesis derives its greatest support from the
health status of the modern Maya in highland Guatemala (Scrimshaw and
Tejada, 1970), who rely on maize for a significant proportion of their daily
sustenance. Together with impoverished Ladino populations, the Maya are
often used in studies of growth and development, and provide models for
poor nutrition and health (Beh~ir, 1977; Bogin, 1988; Bongaarts and Delgado, 1977; Scrimshaw et al., 1968; Sibri~in and E!ston, 1990; Martorell,
1992). However, this direct analogy presupposes that the agricultural base
Human Biology in the Classic Maya Collapse
153
of modern Maya peoples is analogous to that in prehistory and that modern
diets are constrained by long-standing emic cultural preferences. This is far
from the truth. Over the twentieth century, indeed since the sixteenth century, highland Maya peoples have seen their land holdings rapidly diminish
at the hand of coffee plantations, to the point where few families have
enough farm land to provide their basic staple foods (Perera, 1993;
Schwartz, 1990; Stoll, 1993). Hence most concentrate on high-yielding
maize and must buy a large proportion of their food. Since the purchase
of animal protein is not in their grasp, dietary possibilities are further limited. We should also note that, despite widespread malnutrition, high infant
mortality, and political conflict, highland Maya populations have actually
grown at an exponential rate during the twentieth century (Early, 1982).
They are not on the brink of demographic collapse. Although we have ourselves been guilty of drawing too liberally on this modern analogy, it is
important to recall that the highland Maya are not living fossils, but a vibrant people coping with a very different social dynamic than did their
ancestors.
In this paper, we review recent advances in Maya osteology, with the
aim of reevaluating archaeological reconstructions of the diet of the ancient
Maya and the role of nutritional factors in the demographic transition of
the eighth and ninth centuries AD. A florescence of research on Maya
osteology in recent years is the result of larger and more representative
skeletal samples than were available to early workers and rapid advances
in bioarchaeological methodology over the last few decades. In particular,
isotopic techniques provide a new avenue by which to reconstruct food consumption from skeletal remains.
In this review, we distinguish a nutritional argument that is typically
subsumed within ecological explanations of the collapse and find that the
biological evidence for malnutrition as a causative agent of demographic
collapse is weaker than generally assumed. Although the case for an environmental catastrophe can be made independent of the nutritional mechanism, we find little support for generalized ecological models in
paleodietary data. Instead, the Maya Lowlands show considerable diversity
in dietary and health indicators, implying that local environmental and social conditions were key factors defining Classic Maya paleoecology.
LOWLAND MAYA HEALTH: EVIDENCE FROM
PA1,EOPATHOLOGY
Of the abundant pathology documented in osteological studies of
Maya skeletal remains, evidence of anemia, infection, and growth disrup-
154
Wright and White
tion has been marshaled to demonstrate that the Late Classic Maya society
was poorly adapted to its environmental surroundings. In terms of the ecological model, we can ask three critical questions of the paleopathological
data from the Maya lowlands.
(1) What is the total disease burden on the population? How does
it compare to other complex agricultural societies, and to modern
populations whose health status is better understood?
(2) Is there evidence of a change in health status over the span of
Maya occupation? Can we document a gradual deterioration in
health that is correlated with increasing population density?
(3) Is there a relationship between nutritional pathology and food
consumption, as reconstructed isotopically from bone?
These questions arise from the contexts in which osteological data have
been used in the archaeological literature as evidence to support the argument that health deterioration made a critical contribution to the collapse.
For instance, Hammond (1982, p. 140) describes "a decrease in nutritional
standards, detected in the skeletons of Late Classic burials, increased susceptibility to endemic diseases, which may have become epidemic." Likewise,
Freidel and Schele (1990, p. 489) state that "at Copan... the voiceless remains of the d e a d . . , bear witness to malnutrition, sickness, infection, and
a hard life indeed," echoing a common assumption that health "stress levels
increased dramatically in Classic times" (Santley, 1990, p. 329).
With respect to the question of disease burden we must first emphasize
that differing epidemiological circumstances mitigate against direct inference of disease burden from raw frequencies of paleopathological indicators. Because skeletal response to disease is nonspecific and many diseases
do not affect bone, we cannot make absolute statements about the quality
of life. In general terms, however, we can evaluate a common perception
among Mayanists, impressed by Saul's (1972) pathology photos, that disease
was anomalously high among the Maya.
Due largely to Haviland's (1967) proposition that health declined with
increasing population density and agricultural stress at Tikal, ecological
models generally invoke a gradual deterioration in the state of health over
the span of the Classic Period. Hence, we should expect to see an increase
in the prevalence and severity of paleopathological conditions over time.
Admittedly, debate currently wages over paradoxical interpretations of the
relationship between the prevalence of pathology in mortality samples and
the health of the living population from which they are drawn (Cohen,
1994; Goodman, 1993; Jackes, 1993; Wood et aL, 1992). We agree that the
interpretation of paleopathology data is complex and not always intuitive.
Because skeletal data have been used to support an ecological model on
Human Biology in the Classic Maya Collapse
I
N
~ j AJm
tr
Fig. L Map of the Maya area showing the locations of sites mentioned in the text.
155
156
Wright and White
this basis, for the purpose of this review, we follow the traditional assumption that higher levels of skeletal pathology imply poorer health.
With the recent increase in osteological work on the Maya, we are
now in a better position to evaluate the severity of paleopathological data.
Regardless, sample sizes for pathological indicators remain small. In the
tables, we cite the proportion of individuals affected by a condition with
respect to the number of skeletons for which that particular bone element
is present and scorable as reported by each researcher for each skeletal
series. Hence, sample sizes for each site are much smaller than is apparent
from the total number of skeletons excavated. Our review here uses the
data published to date, but we must emphasize that ongoing work will clarify current patterns and no doubt raise further questions. We include data
on Postclassic and Historic health in our review to provide greater time
depth to the observed trends. Moreover, the biological consequences of
the Spanish conquest, although still inadequately documented, provide a
counterpoint to the posited health transition of the Classic collapse. Figure
1 illustrates the locations of sites mentioned in the following discussion.
Paleodemography
Understanding the Classic Maya collapse is fundamentaly a demographic problem. Osteological paleodemographic data have been brought
to bear upon this issue, beginning with Saul's (1972) description of a (statistically nonsignificant) decrease in mean age at death of skeletons from
Late Classic Altar de Sacrificios, a key study which led some to speculate
that elevated mortality had a major impact on the collapse (Willey and
Shimkin, 1973; Santley et al., 1986). Subsequently, Sattenspiel and Harpending (1983) cogently argued that the mean age at death in cemetery
samples bears little relation to mortality. This and other problems inherent
in paleodemographic reconstruction (Bocquet-Appel and Masset, 1982,
1985; Buikstra and Konigsberg, 1985; Van Gerven and Armelagos, 1983;
Wood et al., 1992) are of particular concern in the Maya Lowlands, where
recovery of infant remains is especially compromised.
At present, Copfin is the only Classic Maya site where archaeological
sampling has been adequate to permit a serious attempt at osteological
paleodemography. But even at Cop~m, undersampling of burials from the
earlier phases of occupation limits the reliability of demographic reconstructions of the growth of the Classic Period population (Fash and Sharer,
1991). Using survival analysis, Whittington (1991) suggested that decreased
fertility may have contributed to the decline in the low-status population
of Cop~in. On reanalysis of the same skeletal series using likelihood analysis
Human Biology in the Classic Maya
Collapse
157
to fit model life tables, Paine (1992) concluded that is was not possible to
obtain reliable estimates of fertility, mortality, or migration from the skeletal data alone. However, his event history analyses of settlement abandonment does indicate that residences on prime agricultural land were
maintained longest, providing support for the argument that agricultural
degradation contributed to the population loss. Rather than relying on paleodemography to reconstruct patterns of fertility and mortality, it is more
fruitful at this time to focus on factors that directly affect fecundity and
survivorship, i.e., health and nutritional status.
Nutritional Disease
Anemia
Skeletal manifestations of anemia have played an important role in
the development of the nutritional argument of the ecological model of
collapse. In extreme anemia, the hemopoietic tissues expand to counterbalance the blood deficit (Weatherall and Wasi, 1990). In young children,
the expansion of diplre in the orbits and cranial vault can perforate the
thin external table of bone, producing a distinctive skeletal lesion known
as porotic hyperostosis. In young children, the initial reaction is pitting and
perforation of the orbital roof (called cribra orbitalia) (Stuart-Macadam,
1989). In older children, continued anemic stress produces pitting of the
external table of the cranial vault and the deposition of new perpendicular
bone that is responsible for the characteristic "hair-on-end" radiographic
image (Aksoy et al., 1966; Burko et al., 1961). Because hemopoietic marrow
is gradually replaced by fatty marrow with age, anemia cannot initiate
porotic hyperostosis in adults, although remodeled lesions of childhood
anemia may persist in the adult cranium (Stuart-Macadam, 1985, 1987).
Evidence of anemia, therefore, speaks only to health status during growth
and development, not during later life or, for adults, at the time of death.
Because there is no good evidence of genetic hemolytic anemia as in
the Old World, high frequencies of porotic lesions in New World archaeological skeletons are typically attributed to iron deficiency anemia and
often linked to dependency on maize agriculture (Saul, 1977; E1-Najjar,
1977; E1-Najjar et aL, 1976). In many areas, porotic hyperostosis increases
with the transition to agriculture, supporting the interpretation of the lesion
as an indicator of nutritional stress (Cohen and Armelagos, 1984, p. 587).
However, porotic hyperostosis is also prevalent in skeletal series from a
variety of environmental contexts, indicating that parasitic infection causing
158
Wright and White
blood loss also contributes to the etiology of the lesions (Palkovich, 1987;
Ubelaker, 1992; Walker, 1986).
Hooton (1940) observed porotic hyperostosis on crania from the
cenote at Chichen Itza. The etiology of these porotic lesions was not firmly
identified at that time. Hooton speculated that they might be scorbutic and
ventured that they "may have been caused by dependence upon a diet consisting mainly of maize" (Hooton, 1940, p. 276). He noted that the pathology was abundant and dramatic but not unprecedented, as comparable
examples could be found in skeletal collections from Peru. Nonetheless,
Hooton (1940, p. 276) offered the suggestion that nutritional disease may
have "caused the downfall of the Maya civilization." At the time of his
writing, chronological alignments of Mesoamerican civilizations were uncertain, and the cenote deposits not securely dated. In retrospect, the health
of the Postclassic Cenote skeletons cannot directly address the collapse of
the Classic Lowland Maya, but it did contribute to a perception that the
Maya were anomalously ill.
This nutritional suggestion was later supported by Saul's (1972) observation of frequent anemic lesions during the Classic Period at Altar de
Sacrificios and became the basis for the nutrition argument of the emerging
ecological model of collapse (Willey and Shimkin, 1973). By this time, a
nutritional cause for New World porotic hyperostosis was widely accepted
(Moseley, 1965). Saul documented abundant healed lesions on adult crania
from Altar de Sacrificios and argued that the frequency of anemia was
particularly extreme and contributed to a debilitating health burden that
would have significant impact on population survival.
Ideally, it would be best to examine active lesions of porotic hyperostosis in the skeletal remains of children, but subadult sampling is notoriously poor in the Maya area, due to preservation bias against immature
remains and the combined biases of the dispersed locations of Maya burials
and archaeological sampling strategies. Hence, intersite comparisons of
anemic lesions must emphasize lesions on adult crania. The diagnosis of
porotic hyperostosis in adults is complicated by the extent of sclerotic remodeling, which can mimic other scalp infections. Most researchers require
both porotic lesions and increased vault thickness to identify lesions in
adults, but scoring may not be entirely consistent between researchers. Cohen et al. (1994) suggest that interobserver error may partly account for
the variability reported. For instance, Saul (1972) recorded higher prevalences of lesions at Altar than did Wright (1994) on restudy. However, substantial differences in porotic hyperostosis occur between sites studied by
a single observer (Whittington, 1989; Whittington and Reed, 1996) and
chronologically at a single site (White, 1986; White et al., 1994). Hence,
small differences between studies are not terribly meaningful.
Human Biology in the Classic Maya Collapse
159
Table I. Frequency of Porotic Hyperostosis in Mayan and Comparative Skeletal Series
Adults
Subadults
Skeletal series
Reference
%
N
%
N
12.5
58.8
55.5
77.8
*
*
*
35.8
*
8
17
18
18
3.6
60.0
65.4
52.9
48.0
9.0
17.0
19.4
3.0
28
30
81
17
28?
53
100
185
36
Saul & Saul, 1991
Whittington, 1989
Wright, 1994
Hooton, 1940
Marquez Morfin, 1982
White, 1986
White, 1986
Cohen et al., 1994
Whittington & Reed, 1994
---33.3
14.9
45.9
65.0
19.9
67.8
---393
67
61
20
156
277
Lallo et al., 1977
Maya series
Cuello Preclassic
Copfin Classic
Pasi6n (combined)
Chichen Itz,'t cenote
Playa del Carmen~
Lamanai Postclassic
Lamanai Historic
Tipu Historic
Iximch6
Comparative series
Dickson Mounds
Libben
Arroyo Hondo
California Coastal
Chiribaya AIta, Peru
Canyon de Chelly Pueblo
Chaco Canyon
Nubiab
Medieval York, UK
i
i
34.6
44.4
25.9
51.3
53.3
88.0
83.8
23.2
43.2
106
101
241
54
37
91
17
12
129
183
Mensforth
et aL, 1978
Palkovitch, 1987
Walker, 1986
Burgess, 1996
E! Najjar et aL, 1976
El Najjar et aL, 1976
Carleson et aL, 1974
Grauer, 1993
i
"Subadult data are included with adult statistics for these samples.
bData refer to cribra orbitalia instead of porotic hyperostosis of the cranial vault.
The prevalence of porotic hyperostosis is quite high in Maya series,
reaching 77% in subadults and 65% in adults (Table I). In general, the
subadult prevalences are not out of place with statistics for other maize
growing cultures, such as Woodland and Mississippian North Americans
(Lallo et al., 1977; Mensforth et al., 1978) and Late Intermediate Peruvians (Burgess, 1996). The data are also comparable to Coastal Californians, where the incidence of porotic hyperostosis is linked to parasitism
instead of dietary insufficiency (Walker, 1986). However, they are lower
than in Southwestern Pueblo maize agriculturalists at Canyon de Chelley
and Chaco Canyon (E1-Najjar et aI., 1976), where the prevalence of
porotic hyperostosis may be more firmly linked to maize agriculture,
though differences in parasitism also contribute to the southwestern
trends (Reinhard, 1988). Among adults, the Maya series show more abundant lesions than some North American groups but are comparable to
the Southwestern Pueblo adults. The Maya data are also remarkably similar to the prevalence of porotic hyperostosis recorded for Medieval York,
where malnutrition and infection produced a high level of pathology
(Grauer, 1993). Thus, on the grounds of lesion prevalence alone, we can-
160
Wright and White
not confirm the perception that the ancient Maya were affected by anemia to an anomalous extent.
Substantial geographic variability in porotic hyperostosis expression is
evident among Maya sites. Although scoring differences are undoubtedly
a factor, this regional variation may also be related to differences in both
dietary and parasitic stress loads. Lesions of porotic hyperostosis are unusually abundant among the Chichen Itza cenote skeletons (Hooton, 1940),
and we suspect that children deposited here were not randomly selected
from the local populace. In contrast, it is possible that pathological juvenile
crania are underrepresented at other sites due to their differential decay.
Among adults, the cenote crania show levels of porotic hyperostosis comparable to those of Cop~in and the Pasi6n sites Altar de Sacrificios, Seibal,
Dos Pilas and Aguateca (Whittington, 1989; Wright, 1994). Lower prevalences are recorded for Tipu, Lamanai, Cuello, and Iximch6 (Cohen et al.,
1994; Saul and Saul, 1991; White, 1986; Whittington and Reed, 1996). If
the occurrence of porotic hyperostosis is linked to maize dependency
among the Maya, lower or lighter carbon isotopic values for Classic Period
Lamanai and Preclassic Cuello might explain part of this trend. Anemic
scars are more abundant at Postclassic Lamanai than during the Classic
Period, a change that does seem to be correlated with increased maize consumption (White, 1986). In contrast, at Iximchr, maize consumption as
measured isotopically was high, and yet it has the lowest frequency of
porotic hyperostosis (Whittington and Reed, 1993).
Based on a small sample of skeletons from Tancah with few anemic
lesions, Saul (1977, 1982) suggested that fish consumption at coastal sites
might offset dietary iron deficiency suffered at inland sites. Ironically, fish
are also a source of parasites which could contribute to iron deficiency
anemia (e.g. Walker, 1986). Porotic hyperostosis is certainly abundant at
some coastal sites, such as Playa del Carmen, where M~rquez Morffn et
al. (1982) report the lesions in 48% of skeletons (not separated by age).
Moreover, fish do not contain especially high iron levels (INCAP,, 1961).
We suspect that variability in parasitic infection may account for much
of the variability observed in porotic hyperostosis among the Maya. Scrimshaw and Tejada (1970, p. 208) observe that hookworm infection accounts
for a substantial proportion of anemic cases in Guatemala City hospital
admissions. Although it was once thought that the hookworm Ancylostoma
duodena& was introduced to the New World in historic times, coprolite
evidence now supports an indigenous origin (Reinhard, 1990; Home, 1985).
Climatic variability across the Maya area likely controls the distribution of
the nematode and its impact on human health, as the larvae can survive
only at temperatures between 70 and 85"F (Beck and Barrett-Connor, 1971,
p. 103). Hence, the parasite may be more abundant in the warm lowlands
Human Biology in the Classic Maya Collapse
161
than in the highlands, accounting for the rarity of anemia at Iximch6 and
its abundance at lowland sites. Shattuck (1938) illustrates this elevation effect by recording a substantially higher occurrence of hookworm at lowland
Quirigua than at highland Guatemala City. Climatic effects will be less significant for other parasitic infections contributing to parasitic blood loss,
such as Trichuris, Ascaris, and Strongyloides. It is also interesting to note
that in the lowland Pet6n nearly twice the proportion of deaths was attributed to intestinal parasitism each year between 1986 and 1990 than in the
highland Guatemalan departments of Quich6, Solol~, and Huehuetenango
(INE, 1993).
If the incidence of porotic hyperostosis were tightly linked to dietary
iron deficiency as argued by proponents of nutritional collapse mechanisms,
and nutritional decline contributed to the collapse, we should expect to see
a change in the abundance of lesions over time. In the face of declining
productivity, if farmers concentrate on high-yielding maize to the exclusion
of other crops, following the traditional model, we anticipate increased iron
deficiency anemia over time. Alternately, if maize becomes more scarce
due to environmental degradation and wild foods are substituted for the
deficit of cultigens, one might even expect iron deficiency to improve. Finally, if general food quantity is a problem but there is little change in diet
composition, we should see increased iron deficiency.
At Altar de Sacrificios, Saul (1972) did not document a chronological
change in anemia due to sampling limitations. The sample from Cop~in
analyzed by Whittington (1989) precludes the observation of chronological
trends due to undersampling of early burials. Ongoing work by Rebecca
Storey may soon provide better chronological depth, but these data are
not yet available. More recent reanalysis of the Pasi6n valley skeletal series
from Altar, Seibal, and the Petexbat6n sites (Dos Pilas and Aguateca) confirms no statistical change in the frequency of healed lesions in adults over
time, whether sites are taken independently or the region is considered as
a whole (Wright, 1994). At Lamanai, the frequency of porotic hyperostosis
rises only slightly from the Classic to Postclassic Periods when isotopic paleodiets show a dramatic increase in maize consumption, but increases
much further with the introduction of foreign infectious and parasitic diseases after the Spanish Conquest, a transition not accompanied by dietary
change (White et aL, 1994).
In summary, the data on ancient Maya anemia do not provide unequivocal support for a nutritional collapse argument. The lesions are not
present at anomalous levels when viewed in a global perspective, and
changes over time are not generally documented. The considerable variability in porotic hyperostosis expression is more easily accounted for by
variability in parasitism with climate and human population density. Ane-
162
Wright and White
mia undoubtedly took its toll on the health of ancient Maya peoples, but
we find little evidence to identify it as a causal element of the collapse.
Whittington (1989, p. 306) has argued that anemia did have a critical impact on the decline of Cop~in on the grounds that porotic hyperostosis lesions are negatively correlated with adult survivorship. Among adults,
however, this pattern is anticipated because complete remodeling of lesions
will lower lesion abundance in older adults. No such age trends were documented in anemic lesions in the Pasi6n series (Wright, 1994). At this time
we are unable to resolve the etiological paradox of whether the abundance
of anemic lesions in Maya skeletons is caused by high frailty and susceptibility to a heavy health burden or by high survivorship through protracted
childhood anemia that in turn conferred protection against infectious disease (Stuart-Macadam, 1992).
Scurvy
The second nutritional disease that has received substantial attention
with respect to the Maya is scurvy. Vitamin C is necessary for the hydroxylation of proline in the construction of collagen from its constituent peptides and in the maintenance of the vascular endothelial membrane
attachments (Ortner and Putschar, 1981). A deficiency in childhood leads
to abnormal bone growth with incompletely ossified metaphyses and thin
cortices, which are very susceptible to fracture. Extensive subperiosteal
hemorrhaging is a key result, due to the weakened vascular tissue. In adults,
few skeletal changes occur, other than pathological fractures through rib
metaphyses. Periodontal degeneration may occur, which might lead to antemortem tooth loss (Ortner and Putschar, 1981).
Saul has proposed that subperiosteal new bone, deposited on the shafts
of long bones, indicates that scurvy was common in adults from Altar de
Sacrificios (1972), CueUo (Saul and Saul, 1991), and Tancah (Saul, 1982).
The diagnosis is problematic in that subperiosteal hemorrhaging is unlikely
to calcify under scorbutic conditions due to the inhibition of collagen synthesis. If the patient recovers, some calcification might occur, but this is
typically only at the margins of the hemorrhage and is unlikely to be preserved in archaeological materials. To date, very few osteologists have diagnosed scurvy in archaeological skeletons, and their diagnoses have not
been generally accepted. As Ortner and Putschar (1981, p. 273) note, the
Altar lesions are best interpreted as nonspecific indications of infectious
disease (periostitis), while the periodontal resorption cited by Saul is more
consistent with a diagnosis of antemortem tooth loss secondary to caries
and abscess. In the Maya area, only Kennedy (1983) has followed Saul's
H u m a n Biology in the Classic Maya Collapse
163
diagnosis of scurvy. Other osteologists have not diagnosed scurvy in their
collections (Cohen et al., 1994; White, 1986; Whittington, 1989; Wright,
1994).
Saul supported his diagnosis with the observation that the Yucatec
Maya consumed little fruit in the 1920s. Fruit is somewhat less plentiful in
the dry Yucatan than in the wet lowlands of the Pet6n. Moreover, it is
difficult to estimate fruit consumption in dietary surveys because fruit is
often eaten as a snack food, between meals. Declining fruit consumption
in the twentieth century is likely due to the introduction of processed sugar
(Scrimshaw and Tejada, 1970, p. 208; Danforth, 1989, pp. 20-21). Paleobotanical studies have documented ancient Maya consumption of a variety of
fruits, including zapote, nance, ciruela, hackberry, wild grape, and avocado.
The Itzfi Maya preserve these species among others and there is little reason to suppose that this practice is not of great antiquity (Atran, 1993).
Greens and chile peppers also contain substantial quantities of vitamin C.
These are consumed today and have been recovered from archaeological
flotation samples (Lentz, 1991; Miksicek, 1983). It is unlikely that the ancient Maya were scorbutic.
Growth Disruption
Stature
Reconstructions of skeletal stature have also played an important role
in bolstering the ecological model of collapse. Stature is widely recognized
as a general measure of childhood nutrition and health experience and is
often used to investigate health differentials in modern and archaeological
populations where genetic factors can be controlled. Haviland (1967) observed a decline in both adult male and female stature over the Classic
Period at Tikal and increasing stature divergence between tomb and
nonelite skeletons. Shortly thereafter, Saul (1972) described a comparable
decline in male stature at Altar de Sacrificios.
Danforth (1994) has cogently reviewed the data and issues of stature
change in Lowland Maya skeletons, and we refer readers to her work. In
brief, she notes that the statural data are especially scant due to the limited
sample sizes of adequately preserved remains, so that trends can rarely be
statistically verified. Methodological issues also complicate the utility of this
limited database, especially the large bias introduced by the choice of bone
used, and circularity inherent in using dimensional differences as sex-specific health indices when those same measures form the basis of skeletal
sex classification. As Danforth observes, the trends described for Tikal and
164
Wright and White
Altar have been generalized in subsequent scholarship to a pan-Maya phenomenon, which cannot be confirmed by the limited data available from
other sites. For instance, Santley et al. (1986, p. 142) claim a stature reduction at Barton Ramie that was not identified in the osteological report
(WiUey et al., 1965).
We must also emphasize that the apparent trends at Altar and Tikal
are somewhat suspect. At Altar, the decline in male stature is predicated
upon a sample of only 11 skeletons spread over the 1500-year occupation
span. At Tikal, the trend is more convincing, but is based on a combination
of bone measurements, in situ burial measures, and postexcavation reconstructions from burial plans. Given the highty variable nature of skeletal
slumping with soft tissue decay, even in the absence of other disturbance,
we should be skeptical of the accuracy of these data.
Statural data do not provide unequivocal evidence for a change in
health status during Maya prehistory. Yet the scant data do support the
suggestion, originated by Stewart (1949; 1953), that the modern Maya are
of the order of 5 cm shorter than their prehistoric ancestors, a trend paralleled in other Mesoamerican peoples (Faulhauber, 1970; Genovds, 1970;
Nickens, 1976; Steggerda, 1941; Williams, 1931). Given that the early colonial Maya from Tipu exceed modern statures but are comparable to archaeological data, it seems likely that most of this reduction came about
during Historic times (Cohen et al., 1994; Danforth, 1994) and may be related to nutritional shifts at the hand of Colonial land-tenure transformations as well as increased infectious disease loads. This discrepancy between
ancient and modern populations highlights the questionable utility of analogy with modem health conditions in Maya descendants.
Dental Development
Poor childhood health among the Maya has also been identified
through defects in the developing teeth. Enamel hypoplasias--circumferential bands of depressed, thin enamel--form during the development of
the tooth crown under conditions of metabolic stress. Hypoplasias appear
to be caused by disruption of the secretory phase of enamel formation,
which may occur in a variety of disease syndromes or due to the interaction
of nutrition and disease. Health disturbances that affect only mineral metabolism produce related defects, known as hypocalcifications, which are
irregularly mineralized bands of enamel, that may or may not be associated
with any surface contour hypoplastic lesions (Commission on Oral Health,
1982; Goodman and Rose, 1990). At a microscopic level, brief acute stress
episodes produce narrow bands of defective enamel known as Wilson bands
Human Biology in the Classic Maya Collapse
165
(Rose et at, 1978). Since enamel defects occur at a greater frequency in
the dentitions of subadult skeletons than in those of adults (Cook, 1981;
Goodman and Armelagos, 1988), they are sensitive indicators of childhood
health conditions that contributed to mortality in prehistory.
Because teeth are the best-preserved skeletal element, and on occasion the only material recovered from burials in the Maya area, studies
of enamel hypoplasia among the Maya have been quite productive. However, the results of different studies are difficult to compare because of
different reporting standards and interobserver variability in lesion definition. Hypoplasias have been reported by presence/absence, mean number of defects per tooth, percentage individuals affected, and mean
number of defects per millimeter, or 6-month unit of enamel. Unfortunately, these measures are not readily converted to a scale on which defect
incidence can be compared between studies. Within the dentition, teeth
vary dramatically in the abundance of developmental defects, due to differences in crown architecture, the chronology of tooth development and
stress occurrence, and intertooth susceptibility to ameloblastic disruption
(Goodman and Armelagos, 1985a; b). Accordingly it is crucial that hypoplasia investigations treat tooth positions consistently and control for
missing teeth. Finally, although intraobserver error does not appear to be
too severe, investigators may differ substantially in the identification of
the less severe hypoplastic events (Danforth et al., 1993). Hence, it is not
feasible to draw broad health comparisons between sites with hypoplasia
data at this time.
Saul (1972) documented abundant hypoplasia on teeth at Altar de Sacrificios and equated the lesions with weanling stresses, thereby painting a
picture of poor childhood health. Several investigators have reported that
hypoplasias are observed in the dentitions of almost all adult skeletons,
indicating a high prevalence of childhood stress episodes, through which
the individuals survived (Kennedy, 1983; Saul, 1972, 1973, 1975, 1982, Whittington, 1989, 1992; Wright, 1994). Moreover, Storey (1992a, b) has documented abundant hypocalcifications in deciduous teeth of elite children at
Cop~in, indicating inadequate maternal buffering of stress to children in
utero. But as Whittington (1992, p. 194) notes, the abundance of lesions is
not out of line with that documented for other skeletal series, including
Barbados slaves (Corruccini et al., 1985), the Bronze Age Levant (Smith
et aL, 1984), the precontact Georgia coast (Hutchinson and Larsen, 1988),
Dickson Mounds (Goodman and Armelagos, 1985b), and the HammanTodd collection (EI-Najjar et aL, 1978).
Although direct comparison of data collected by different investigators
is hindered by differences in reporting and interobserver error, there is little
evidence to suggest that childhood health varied dramatically across the
166
Wright and White
Maya lowlands. Danforth (1989, 1996) reports no significant differences in
the abundance of enamel hypoplasias or Wilson bands in deciduous and
adult teeth between Late Classic skeletal series from Tikal, Seibal, and Barton Ramie, despite the discrepancy in social status that might be anticipated
among these series.
Chronological trends in hypoplasia incidence have been examined at
Cop~in (Whittington, 1989, 1992), Lamanai (White, 1986), and Altar de
Sacrificios (Saul, 1972) and in the combined Pasi6n series (Wright, 1994).
None of these studies reports any statistically significant differences between phases in the total level of stress experienced. Although Classic Maya
children suffered a severe health burden, there is no indication that health
deteriorated over time or with increasing population density and postulated
demographic pressure.
It is interesting to note that Danforth (1989) reports a substantially
higher prevalence of hypoplasias and Wilson bands in the Late Classic
Pet~n series than at Colonial Tipu, indicating that childhood health was
indeed worse during the Late Classic Period. This finding seems to contradict the statural data, which indicate continuity between Classic and
Colonial Petdn populations. However, both anemia and infection seem to
be anomalously rare at Tipu (Cohen et al., 1994), raising the possibility
that this settlement had the luxury of more sanitary living conditions, perhaps a consequence of the lower population density. The situation is reversed at Lamanai, where Wilson band frequencies imply an increase in
acute morbidity during the early Colonial era over the Postclassic condition. Given the coeval increase in porotic hyperostosis at Lamanai, it is
reasonable to attribute this change to Spanish-introduced infectious and
parasitic diseases (White et al., 1994; Wright, 1990). Unfortunately, no local Postclassic skeletons are available from Tipu to examine this transition
directly.
Infectious Disease
Infectious disease has been an important element in the ecological
model of collapse. Instead of epidemic disease, such as the yellow fever
epidemics once proposed by Spinden (1928), infectious disease is generally
incorporated into collapse models as a factor operating in synergism with
malnutrition, and contributing to an overall poor health status. The role
of infectious disease in the collapse was championed by Shimkin (1973),
who suggested that Chaga's disease (American trypanosomiasis), Ascaris,
yellow fever, and enteric pathogens causing weanling diarrhea may have
played a significant role in the deteriorating health of Late Classic popu-
Human Biology in the Classic Maya
Collapse
167
lations. The only skeletal evidence that directly addressed infectious disease
at that time was the diagnosis of treponemal infection in the skeletal remains from Altar de Sacrificios, Seibal, and Zaculeu (Goff, 1953; Saul,
1972, 1973), a condition which Saul rightly did not link to his otherwise
bleak view of Maya health.
The synergistic interaction of infectious disease with malnutrition is
widely recognized as a critical element of weanling diarrhea and subadult
morbidity and mortality in disadvantaged populations (Scrimshaw et aL,
1968). Undoubtedly, this process operated among the Maya, as indicated
by the prevalence of developmental enamel defects and porotic hyperostosis. We have already examined the role of intestinal parasitism with respect to childhood anemia among the Maya. Infectious disease can also be
studied directly in skeletal remains through the investigation of subperiosteal bone inflammation--periostitis--a common response to infection.
Disturbance of the periosteal membrane by infectious agents results in the
deposition of a thin layer of fibrous new bone on the surface of the existing
bone cortex. On recovery from the infection, this new bone is remodeled
and gradually integrated into the underlying cortex. Thus, the state of periosteal reactions gives clues to the status of the infection that produced
them, be it active or healed.
Periostitis occurs in a variety of infectious syndromes including respiratory and enteric diseases, as well as systemic bacterial infections (such
as Staphylococcus) and localized infections due to overlying skin trauma
(Greenfield and Schorsch, 1967; Ragsdale et al., 1981; Resnick and Niwayama, 1981). Bone responds to infection in a nonspecific manner that
does not allow the diagnosis of most infectious agents, so the abundance
of periostitis in skeletal samples is often taken as a proxy for infectious
disease in general. Analyses of periostitis and porotic hyperostosis in the
skeletons of young children have confirmed a strong association between
the conditions that support the synergistic role of infection in subadult morbidity and mortality (Lallo et al., 1977; Mensforth et aL, 1978). The infectious agent responsible for periosteal reactions in a skeletal series can
occasionally be inferred from their form, and the intraskeletal and populational distribution of the lesions, although it may not be possible to diagnose the specific cause of individual lesions (Buikstra and Cook, 1980;
Cook, 1976; Ragsdale et aL, 1981).
Periostitis has been systematically studied at relatively few Maya sites.
In many cases, the lesions have been noted, but not treated in a manner
that permits populational evaluation or differential diagnosis of underlying
disease processes. Table II presents summary statistics on the abundance
of periostitis on femora and tibiae in Maya series and comparative data
from other well-studied skeletal series. Long bone infection occurs at
168
Wright and White
Table 11. Frequency of Diaphyseal Periosteal Reactions in Adults in Mayan and
Comparative Skeletal Series
Femur
Tibia
Skeletal series
%
N
%
N
Maya series
Pasi6n (combined)
37.3
75
68.0
75
Tipu
--8.4
704
Cop~in
43.5
46
55.3
38
Comparative series
Moundville, ALa
19.3
419
58.5
434
Gibson, ILa
60.0
45
84.4
32
Ledders, ILa
38.1
21
63.6
22
Ft. Ancient, OH
10.6
160
24.3
136
Jomon, Japan
5.1
332
12.6
324
Medieval York, UKb
13.9
466
61.8
466
Nubia, X-Groupc
3.4
129
--aSeries in which treponematosis has been diagnosed.
bSubadult data are included with adult statistics for these samples.
CBoth tibial and femoral periostitis considered together.
Reference
Wright,1994
Cohenet at, 1994
Whittington, 1989
Powell, 1988
Cook, 1976
Cook, 1976
Perzigianet al., 1984
Suzuki,1991
Grauer,1993
Armelagos, 1968
roughly equivalent levels at Cop:in as in the Pasi6n valley sites, with somewhat more than half of adults having tibial lesions (Whittington, 1989;
Wright, 1994). Colonial Tipu is very different, with very few skeletons showing periostitis. The difference is likely due to the apparent absence of trep o n e m a l i n f e c t i o n at Tipu ( C o h e n et al., 1994). Lesions typical o f
nonvenereal treponematosis have been documented in the Pasi6n series
(Saul, 1972; Wright, 1994) and may be present at Cop~in (Whittington,
1989) and Lamanai (Helmuth, personal communication). Maya skeletons
show an intraskeletal distribution of periostoses consistent with that of endemic syphilis and yaws. Given the rarity of cranial lesions and the tropical
lowland environment, the syndrome may have closely approximated that
seen in yaws today (Wright, 1994). It is important to note that the biological
cost of endemic treponematosis is not especially high, despite its high visibility in skeletal series (Powell, 1991).
The prevalence of periostitis at Cop~in and in the Pasi6n is comparable
to that in other nontropical skeletal series with evidence of endemic syphilis, such as MoundviUe (Powell, 1988), and Woodland Illinois (Cook, 1976).
Series lacking treponemal infection show substantially fewer periostoses, as
among Japanese Jomon peoples (Suzuki, 1991) and ancient Nubians (Armelagos, 1968). We note also that infectious lesions in Medieval York
(Grauer, 1993) are as abundant as among the Classic Maya. These patterns
highlight the difficulty in comparing skeletal health among populations of
differing epidemiological environments but, at the same time, reveal that
infectious disease was not anomalous in the Maya lowlands.
Human Biology in the Classic Maya Collapse
169
Although treponemal infection might account for the bulk of periostitis
at some lowland Maya sites, other infections, in synergism with nutritional
stress, undoubtedly contribute to the overall picture. Because parasitic and
infectious disease load is dependent on host density, and increased forest
clearance with human population density would have reduced alternate
nonhuman hosts for vectored diseases in the Classic Period, Santley et al.
(1986) argue that infectious disease would have increased toward the end
of the Late Classic Period. This hypothesis is not supported by the data
from the Pasi6n region, where frequencies of infection remain stable from
the Preclassic through Terminal Classic Period, whether sites are considered
individually or together. At Cop~in, Whittington (1989) identified a statistically significant decline in the frequency of periostitis between Early and
Late Coner phases, which he attributes to a greater risk of infection in the
core population than in rural noncore sites, combined with migration out
from the core after the political collapse of the Copfin dynasty. He postulates that the decline in periostitis reflects a deterioration of health due to
elevated child mortality and thereby the removal of a greater proportion
of frail individuals, leaving only robust individuals among the adult skeletal
remains. As we noted above, the interpretation of trends in skeletal pathology is complicated by frailty issues. A more traditional interpretation
of these data would see the decline as evidence for improved health, a
paradox we are unable to resolve at this time.
CLASSIC MAYA DIETS: ISOTOPIC EVIDENCE OF
SUBSISTENCE CHANGE
The Paleodiet Revolution
Bioarchaeological investigations have undergone a dramatic advance
over the last two decades with the development of methods to examine directly the composition of the diets consumed by prehistoric peoples though
chemical analysis of bone. Paleodietary methods provide a direct means of
examining consumption on an individual level and, thereby, determining the
relationship between diet and health directly. This development allows more
explicit testing of bioarchaeological hypotheses regarding subsistence change
and the impact of diet on population health and adaptation.
The most promising approach exploits systematic isotopic fractionation
of carbon and nitrogen atoms at each trophic level in the foodweb. While
the stable isotopes of an element have identical chemical properties, their
natural distribution is, in part, governed by kinetic effects of mass differences. Isotopic ratios, measured relative to a known standard, are given as
-30
'
'
-25
C3 N2-fixing plants
C3 plants
{f.w. snail meat
freshwater fish meat
613C
(%. PDB)
-20
i
terrestrial herbivore meat
i
-15
mollusc
meat
reef
-1o
i
C A M & C 4 plants
reef fish
meat
~
i
5
Fig. 2. t~otopic composition of the edible portions of Mayan foods. Carbon values have been corrected for anthropogenic enrichment in
--C to estimated Classic Period values. Food values were compiled from data of Wright (1994) and Tykot el al. (in press).
-35
0
,t
6
2;
Lm
8
g
10
12
14
g
i
~.
0
Human Biology in the Classic Maya Collapse
171
the 8 ratio of the heavier to the lighter isotope. For carbon, the ratio
13C/12C, or ~513C,is calibrated relative to Pee Dee Belemnite (PDB), a marine limestone; likewise for nitrogen, the ratio 15N/~aN, or ~515N,is calibrated
relative to atmospheric N2, air. Because the isotopic compositions of foods
are passed on to the tissues of consumers in a characteristic manner, we
can reconstruct prehistoric diets from the isotopic signature of archaeological skeletons (Ambrose, 1993; DeNiro, 1987; Schwarcz and Schoeninger,
1991; van der Merwe, 1982). Although specific proportions of menu items
cannot be precisely identified in complex diets, the stable isotopic composition of bone can characterize the relative contributions of the primary
dietary components. This method constitutes the most accurate means to
examine prehistoric food consumption available at this time.
Figure 2 illustrates the isotopic composition of most foods available
to the ancient Maya. The stable isotopes of carbon are differentially incorporated into plant tissues during photosynthesis because of enzymatic diff e r e n c e s in CO2 fixation. Plants using the Benson-Calvin or C3
photosynthetic path have a tissue ~13C near -27%0, relative to PDB. Dramatically more enriched, or heavier values occur in plants using the HatchSlack or C4 pathway, which average -13%o (O'Leary, 1988). In the Maya
area, most wild plants and cultigens employ C3 photosynthesis and have
light isotopic values, including beans, squash, roots, and fruits. The most
important exception is maize Zea mays, which uses the C4 pathway and is
enriched in the heavier isotope, 13C, so carbon isotopes can be used as a
proxy for maize consumption in the Maya area. To our knowledge, amaranth Amaranthus spp. and epazote Chenopodium ambrosoides are the only
other C4 plants that might have contributed to the Maya diet. A third
group, using the Crassulacean acid metabolism (CAM) pathway, often resembles C4 isotopic signals but may have lighter values depending on variable use of daylight photosynthesis. CAM plants that might confound with
maize signals in the Maya paleodiet include the nopal cactus Opuntia, the
pifiuela Bromelia karatas, and possibly the pineapple Ananas cosmosus, but
may not have been extremely important to the diet.
Carbon from animal protein would also contribute to enriched signatures in carnivorous diets due to trophic enrichment in protein metabolism,
but pass on the dietary preferences of the herbivore consumed. Most terrestrial fauna in the Maya area consumed wild C3 flora (or lived in C3based foodwebs), but isotopic evidence confirms that some animals have
C4-1ike signals, such as dogs, which were regularly fed or scavenged C4
foods (probably maize) (Tykot et al., 1996), and occasional deer and peccary, which are known to feed at the margins of maize fields (White and
Schwartz, 1989; Wright, 1994). Marine fish from the Caribbean have an
enriched carbon isotopic content similar to that of maize (Keegan and
172
Wright and White
DeNiro, 1988; Tykot et al., 1996) and could confound the signature unless
used in conjunction with nitrogen isotopes, but freshwater Petdn fish resemble C3 plants in ~13C (Wright, 1994). Likewise, marine mollusks are
more enriched in ~13C than are freshwater snails from the Pet6n (Tykot et
al., 1996; Wright, 1994).
Nitrogen isotopes do not differ dramatically between plant types, although legumes such as beans, Phaseolus vulgaris, contain symbiotic bacteria that fix atmospheric nitrogen thus have a 515N near 0%0, slightly lower
than other plants with a ~lSN near 2-5%o. Nitrogen isotopes are particularly useful as indicators of the trophic position, because 15N is fractionated
at each level of the foodweb, with consumers having ~lSN about 3%0 heavier than the food they consume (DeNiro and Epstein, 1981; Schoeninger,
1985). In the Maya area, marine fish are not as enriched in 15N as in boreal
waters (Keegan and DeNiro, 1988) but would raise the consumer ~15N
more than the consumption of terrestrial protein. Likewise, freshwater fish
are even more enriched in 15N, and their consumption would raise the ~15N
disproportionately (Wright, 1994).
Stable isotopic analysis has generally made use of collagen--the organic portion--in archaeological bone, and the isotopic data obtained from
the Maya area to date are principally collagen data. Recent advances have
focused on ~13C in bone apatite--the inorganic portion--and the differences between collagen and apatite ~13C. At this time, most paleodiet researchers concur that dietary protein is preferentially routed to synthesis
of collagen, so collagen data should be interpreted with some bias toward
the protein component of prehistoric diets. In contrast, carbon atoms in
bone apatite seem to be drawn from the total dietary pool of all nutrients
ingested (Ambrose and Norr, 1993; Krueger and Sullivan, 1984; Lee-Thorp
et al., 1989; Tieszen and Fagre, 1993). Hence, apatite values may be more
indicative of agricultural foods than collagen, which would include both
plant and animal proteins. Work currently under way in both our laboratories on apatite of Maya skeletons (see also Coyston, 1994; Gerry and
Krueger, 1997; Wright and Schwarcz, 1996) may modify the trends that we
review here, which are based on the ample collagen data currently available
from the Maya Lowlands,
Paleodiet of the Ancient Maya
To date, isotopic techniques have been used to investigate paleodiet
at 14 Classic Lowland Maya sites, located primarily in Belize, Pet6n, and
the southeastern region (Fig. 1). To our knowledge, no isotopic work has
yet been undertaken in the Northern Maya Lowlands, and only one high-
6
-14
7
8
'
|
-12
I
-13
i
~
,
i
-t0
,
i
-9
i,
i
-8
i
,
I- +
T-II
613C (%0 PDB)
-11
I
I
. .k I-7-
i
-7
,
-6
Lamanai
Pacbitun
Barton Ramie
Baking Pot
Holmul
Uaxactun
Altar de Sacrificios
Seibal
Dos Pilas
Aguateca
Itzltn
[] Cop/m
V Mojo Cay
,I. Iximch~
[3
9
O
A
@
9
9
O
[]
II
9
Fig. 3. Mean isotopic composition of human collagen at Maya sites. Error bars represent one standard deviation to either side
of the mean. Data are taken from various references cited in Table IlL In the center of the graph, mean values for Holmul,
Seibal, and Aguateca are nearly coincident.
Z
9
lq
11
12
o_
la
~~
r
O
gg
gl
3I J
=
174
Wright and White
land site has been examined. All of these projects have shown that ancient
Maya diets relied heavily on maize agriculture from Preclassic times on.
However, a substantial degree of geographic, temporal, and social variability in isotopic results indicates considerable diversity of dietary strategies
among the ancient inhabitants of the Maya Lowlands.
Geographic Patterning
Figure 3 illustrates the mean values obtained at a number of sites.
Table III lists the mean values and number of individuals sampled by site.
These data include all chronological periods from which skeletons have
been sampled, and are not controlled for social status or sex. We discuss
chronological and social variability further below.
In the ensuing interpretation of diet compositions we generally assume
that the bulk of foods consumed at any given site was also cultivated or
collected locally. Although trade of foods was documented in the Colonial
Period (Roys, 1943), it is likely that imported foods provided a relatively
minor proportion of nutrients ingested and were perhaps limited to occasional elite delicacies, such as fish (Lange, 1971). Bulk transport of basic
staples has been proposed for some regions, especially the Central Pet6n
(Sanders, 1973; Harrison, 1990), but little evidence can be marshalled to
document this. On the contrary, the local specificity of trace elemental dietary signatures in the Pasi6n region provides a strong case that most foods
were obtained locally (Wright, 1994; 1995).
With the exception of Lamanai, which shows a large shift over time,
a broad distinction can be drawn between the isotopic composition of collagen from Belizean versus inland Pet6n sites (Gerry and Krueger, 1997).
Preclassic and Classic Lamanai (White and Schwarcz, 1989), Baking Pot,
Barton Ramie (Gerry, 1993), and Cuello (Tykot et al., 1996) differ from
Pet6n sites in showing much lighter carbon isotopic signatures. This result
presumably indicates that maize agriculture was substantially less important
to local diets at the Belizean sites than in the Pet6n. Sites farther inland
show more 13C enriched collagen, as at Altar, Seibal, Dos Pilas, Itzfin, and
Aguateca (Wright, 1994). Likewise, Pacbitun (White et al., 1993) and
Holmul show enriched "Pet6n" signatures (Gerry, 1993). Uaxactun clusters
with the Belizean sites (Gerry, 1993).
Although differences in 813C have traditionally been interpreted in
terms of variation in maize consumption, recent data and interpretations
of isotopic metabolism ~ggest that discrepancy in faunal consumption may
be involved. Since dietary protein contributes preferentially to collagen synthesis, animal foods may be as important as maize in defining the ~513C,
Lamanai
Pacbitun
Barton Ramie
Baking Pot
Holmul
Uaxaetun
Altar de Sacrificios
Siebal
Dos Pilas
Aguateca
Itzan .
Copan
Mojo Cay
Iximche
Site
-10.84
-9.86
-11.24
-11.03
-9.38
-10.65
-9.4
-9.4
-9.05
-9.56
-9.17
-9.26
-8.46
-7.78
Mean
2.37
1.39
1.42
1.11
1.27
1.09
1.37
1.16
0.98
0.69
0.30
0.72
0.38
0.40
SD
50
17
38
9
14
6
38
34
19
8
5
46
8
13
N
9.81
9.32
8.8
9.2
9.3
9.4
8.6
9.39
9.57
9.35
7.96
7.56
10.13
7.92
Mean
0.89
0.67
0.44
1.34
0.84
0.97
1.02
0.97
1.05
1.16
0.98
0.48
0.92
0.40
SD
47
17
38
9
15
5
38
34
19
7
5
46
8
13
N
Reference
White and Schwarcz, 1989
White et al., 1993
Gerry, 1993
Gerry, 1933
Gerry, 1993
Wright, 1994
Wright, 1994
Wright, 1994
Wright, 1994
Wright, 1994
Wright, 1994
Reed, 1994
Norr, 1991
Whittington and Reed 1992
Table III. Mean Isotopic Compositions of Human Bone Collagen at Maya Sites
i
813C
815N
9-
~~
9.
m
3
176
Wright and White
despite a smaller proportion to the total diet. Freshwater fish are about
5%o lighter than terrestrial herbivores in the Maya Lowlands (Wright,
1994), so populations consuming more fish than terrestrial meat would have
a lighter ~13C, even with equal maize consumption. It may be revealing to
note that the Belizean sites with a light ~513C are all located in riverine
environments. In contrast, the site of Pacbitun shows an enriched "Petdn"like 813C (White et al., 1993), although it is farther east than the riverine,
light-513C sites Barton Ramie and Baking Pot (Gerry, 1993). Unlike the
riverine Belizean sites, Pacbitun is located inland and would not have had
direct local access to sustainable freshwater fish populations.
Moho Cay, at the mouth of the Belize River, also stands out from the
generally light Belizean sites, having an enriched fi13C value similar to that
of the Petdn sites (Norr, 1991). However, its maritime location, faunal assemblage, and slightly enriched ~15N of collagen reveal that the consumption of marine fauna contributes to the high fi~3C of the collagen.
Among Petrn sites, less variation is evident among riverine and "inland"
sites. Inhabitants of Holmul (Gerry, 1993) had less local access to surface
river fauna, but light 513C values are not observed at riverine sites in southwestern Petrn either--Altar de Sacrificios, Seibal, Aguateca, and Itz~in
(Wright, 1994). It is unclear why Uaxactun should resemble Belizean sites
more than other Petdn sites, but since all skeletons sampled were from Structure A-V, an elite "palace," and most are female (Gerry, 1993), a social or
sexual distinction may be at play. As yet, we have no data on lacustrine
populations from the Central region. The 13C-enriched collagen of Pet6n
sites is probably due to greater maize consumption. However, protein from
C4 plant-consuming animals such as deer, peccary, and dogs may also contribute to the collagen signal. The 515N of Petdn human collagen is more
enriched than that of herbivores, falling into the range of terrestrial carnivores, thereby indicating substantial meat consumption (Wright, 1994).
In the southeastern region, paleodiet has been studied only at
Cop~in, which shows a generally "Petdn"-like 613C-enriched signature
(Gerry, 1993; Reed, 1994). However, the filSN is substantially lighter than
collagen from any other Maya site, falling squarely in the realm of herbivorous mammals. This result implies that animal protein was less important to ancient Cop~n diets than at other sites. If faunal meat
contributes less to the enrichment of ~13C, then maize reliance may have
been greater at Cop~in than elsewhere. Cop~n is located at about 600 m
asl, a higher elevation than the lowland Petdn and Belize sites examined
(20 to 250 m asl). Instead of diverse broadleaf forest, the hills surrounding the Cop~in Valley support pine forest, an environment very different
from that of the Pet6n. This marked ecological distinction, undoubtedly
tied to differences in the diversity and abundance of wild game, may have
Human Biology in the Classic Maya Collapse
177
had a more profound role in shaping Copfin diets when compared with
the Pet6n than social factors such as population density, although the
two issues are difficult to separate.
It is interesting to note that Late Postclassic highland Iximchd collagen
also shows a quite low 515N, although it is slightly more enriched than at
Copfin. Despite Iximchd's much higher elevation (2200 m asl), ecologically
it resembles Copfin more closely than the lowland sites, so the comparable
nitrogen data support the suggestion that environmental parameters contribute to the distinction of Copfin 515N. Altitude has a direct impact on
~13C values in flora, so collagen is more enriched in 13C at Iximch6 than
elsewhere, which should not be taken as evidence for greater maize reliance
(Whittington and Reed, 1994, 1996).
Chronological Patterns
Attention has been drawn both to the bulk composition of Maya paleodiets as evidence for an environmental stimulus for the collapse (Reed,
1994) and to regional variability in isotopic data as evidence against it
(White et al., 1993). The role of dietary factors in the collapse will be most
securely evaluated through investigation of chronological patterns in consumption that are implicated as causal mechanisms of nutritional deterioration in the ecological model. Table IV contains a s u m m a r y of
chronological trends in 813C and ~15N at various sites.
The first attempt to study Maya diet with isotopic techniques revealed
the most extreme chronological shift documented to date (White, 1986;
White and Schwarcz, 1989). However, it is difficult to interpret the Lamanai
data in terms of subsistence implications for the collapse since the community prospered through to historic times. Lamanai collagen had 513C comparable to CueUo in the Preclassic (-12.5%o) and which declined during the
Classic Period to a low of-15%o in the Terminal Classic Period. During
Postclassic and Historic times, 813C increased dramatically to a "Pet6n"-like
value of -9.5%0 (White and Schwarcz, 1989). Although increasing maize
dependence is certainly the primary factor behind this ~13C transition, a shift
from consumption of freshwater fish to marine fish in the later period could
contribute to the 813C shift. An increase in consumption of maize-fed anim a l s - s u c h as turkeys, which were first domesticated in the Postclassic
(Hamblin, 1984)--is also a possible factor. A Postclassic shift toward marine
foods would also be consonant with changing trade and regional interaction
networks at this time, which shifted from southwestern overland interaction
with the Petdn, to north and eastern interaction with Yucatan and the Belizean cays via maritime trade (Pendergast, 1986).
178
Wright and White
Table IV. Chronological Trends in
~13Cand 815N of Collagen from Classic Maya
Skeletons
813C
Site & period
Mean
SD
Lamanaia
Historic
-9.9
0.9
Postclassic
-9.3
0.8
Terminal Classic
-15.0
1.2
Late Classic
-14.2
1.1
Early Classic
-12.3
1.6
Preclassic
-12.7
0.0
Pacbitun b
Terminal Classic
-10.63
1.5
Terminal Classicc
-9.9
1.4
Late Classic
--8.5
1.3
Early Classic
-9.2
-Altar de Sacrificiosa
Terminal Classic
-9.0
0.9
Late Classic
-8.3
1.0
Early Classic
-9.1
0.5
Preclassic
-10.4
0.6
Dos Pilasa
Terminal Classic
-9.4
0.8
Late Classic
-9.0
1.0
Seibala
Terminal Classic
-9.4
1.2
Late Classic
-9.4
1.4
Preclassie
-9.6
1.0
aData from White and Schwarcz (1989).
bData from White et al. (1993).
CControUed for status, age, and sex variation.
dData from Wright (1994).
815N
N
Mean
SD
N
10
24
7
3
4
2
9.7
9.5
9.9
10.3
10.9
10.2
0.6
0.9
0.4
0.1
1.5
0.6
9
24
6
2
4
2
18
8
3
1
9.3
9.2
9.3
8.1
0.7
0.6
0.6
--
16
8
3
1
16
7
5
8
8.8
9.0
8.2
8.4
1.1
1.0
0.6
0.7
16
7
5
8
4
14
8.8
9.8
1.2
0.9
4
15
16
11
7
8.9
9.9
9.7
0.9
0.9
0.8
16
11
7
Less d r a m a t i c t r e n d s are s e e n at sites f a r t h e r inland. A t P a c b i t u n , the
s a m p l e o f L a t e Classic burials s t u d i e d isotopically is small b u t c o n f i r m s a
statistically significant decline in 613C b e t w e e n the L a t e a n d t h e T e r m i n a l
Classic o c c u p a t i o n s ( W h i t e et al., 1993). T h i s is a c c o m p a n i e d by a slight
n o n s i g n i f i c a n t i n c r e a s e in ~15N. This t r e n d is p a r a l l e l e d at two sites f r o m
t h e s o u t h w e s t e r n Pet6n. A t A l t a r d e Sacrificios, 613C i n c r e a s e d f r o m P r e classic t h r o u g h L a t e Classic times a n d t h e n d e c l i n e d slightly in the T e r m i n a l
Classic p o p u l a t i o n (Wright, 1994, 1997). N i t r o g e n i s o t o p e s r e m a i n e d s t a b l e
t h r o u g h o u t t h e A l t a r s e q u e n c e , implying stability in m e a t p r o c u r e m e n t syst e m s a n d t h a t the 6t3C t r e n d s a r e d u e to shifts in t h e relative i m p o r t a n c e
o f m a i z e versus C3 plants. A t D o s Pilas, a few burials f r o m t h e s m a l l postc o l l a p s e o c c u p a t i o n show slightly lower 813C t h a n t h e L a t e Classic p o p u lation, p a r a l l e l i n g the t r e n d at A l t a r (Wright, 1994, 1997).
Human Biology in the Classic Maya Collapse
179
A very different pattern is found at Seibal, where the 513C is stable
over the full sequence from Late Preclassic through Terminal Classic times.
It is revealing to note that Preclassic Seibal diets differ significantly from
their contemporary neighbors at Altar, having a much more enriched ~513C
and ~15N, a fact which demonstrates that cultural as well as environmental
conditions shaped the ancient diet (Wright, 1994, 1997). In the face of
chronological stability in 513C at Seibal, ~515Ndeclines from Late to Terminal Classic Periods. At Seibal, the nitrogen isotopic composition of collagen
differs from other Pasi6n sites in being significantly more enriched, so the
decline in ~51SN,which brings Terminal Classic values into line with neighboring sites, may be due to a shift from emphasis on aquatic to terrestrial
fauna, rather than a decline in absolute meat consumption, a trend also
implied by Sr/Ca and Ba/Ca levels in bone mineral (Wright, 1994).
In sum, these data confirm that prehistoric diets did vary in concert
with major events in Maya history. However, all sites do not show an
equivalent subsistence reaction with the impending collapse. Santley et al.
(1986; Santley, 1990) argue that maize consumption rose with increasing
population density and environmental degradation. This idea found some
support in pollen data from Central Petdn (Wiseman, 1985), that are now
in doubt due to more recent paleolimnological work (Brenner et al., 1990).
A Terminal Classic increase in maize production is not supported by isotopic data for maize consumption at any site. In fact, if any trend is apparent, it is toward declining maize consumption in the final occupations
at Pacbitun, Altar, and possibly Dos Pilas. Indeed, the Terminal Classic decline in 813C at Pacbitun is interpreted as support for an ecological model
of collapse at this particular site (White et al., 1993). Because the Terminal
Classic is the period of greatest population density and investment in agricultural intensification at Pacbitun, White interprets the isotopic data to
mean that maize production capacity was at its limit and that inhabitants
were forced to find alternate C3 foods.
This interpretation does not fit so well for Altar de Sacrificios and
Dos Pilas, however. In both cases, the Terminal Classic occupation postdates the collapse of the elite authority structure. At these two sites, as at
Pacbitun, Terminal Classic collagen is slightly more depleted in laC than
in the preceding Late Classic Period, indicating a decline in maize consumption. While the population remained sizable at Altar, it was very much
reduced at Dos Pilas, so larger yields of maize relative to the smaller population should have been attainable. If agricultural production had reached
a critical threshold in the Terminal Classic Pasi6n, we would expect carbon
isotopic shifts at Seibal, where Terminal Classic population density was
greatest and elite political authority maintained longest, but these do not
occur.
180
Wright and White
Why then did maize consumption decline at some sites? We can envision two scenarios that might lead to declines in total maize production
and, thereby, consumption. (1) Degradation of the agricultural landscape
by overworking could remove land from production as posited in ecological
models of collapse, thereby lowering total yields of maize. Such agricultural
failure would also affect the capacity for production of C3 foods, however,
resulting in a deficit of all agricultural and wild foods. Therefore, this scenario implies a state of Widespread and calamitous undernutrition, which
as reviewed above, is not supported by the paleopathological data. (2) Sociopolitical turmoil at the end of the Classic Period shifted the role of elite
authority away from subsistence concerns, leaving agricultural decisions
more firmly in the hands of local autonomous farmers or to a decoupling
of dietary behavior from state ideology. Certainly maize symbolism was a
critical element of Classic Maya ideology. The relationship between religious iconography and agricultural practice is presumably a reinforcing cycle,
and the possibility that high maize consumption was partly accentuated by
the ideological role of this cultigen should not be ignored. Moreover, tribute or taxation that was paid with agricultural produce must have influenced the mix of crops planted by farmers, thereby shaping the diets of
the populace at large. Changes in the role of elites in agricultural management are likely to be variable as the extent of state involvement in agriculture may not have been consistent across the ancient Maya landscape
and from polity to polity.
As direct measures of diet, the isotopic data might already be revealing
indirect evidence of varied state interests in agriculture or, alternately, state
activities which affect food economy. For example, maize consumption at
Lamanai is lowest during the Terminal Classic Period, which might be taken
as evidence of agricultural failure, were it not for the fact that intensive
political and economic activity is simultaneously indicated by the construction of substantial monumental architecture. White (1986) interpreted this
combination of facts to mean that either trade patterns in foodstuffs
changed significantly or, more likely, the elite were exercising a labor tribute which had a high cost for maize production. Farmers may not have
been able to meet the labor demands of both monumental construction
and intensive agriculture at the same time. For long-term survival of the
Lamanai polity, the economic shift was a successful strategy. Diet may have
been affected by decisions of state rather than by environmental limits.
Moreover, this dietary shift implies the ready availability of alternate foods.
Although it is tempting to align changes in maize consumption with agricultural success, we must remind ourselves that maize may be replaced by
other cultivated crops, not only by recourse to foraging of wild foods.
Human Biology in the Classic Maya Collapse
181
Social Patterns
Political control over the food economy can also be reflected in status
differences in diet within a population. As Fried (1967, p. 186) noted, we
anticipate that high-status individuals had privileged access to "the basic
resources that sustain life." The identification of status groups within ancient Maya populations is a thorny issue. Social distinctions can be identified through settlement patterning, architectural complexity, artifact
distributions, and mortuary remains. For integration with paleodietary data,
burials provide individual assessments of status that hold the most promise.
Although recent work is beginning to address the social implications of
Maya funerary behaviour (McAnany, 1995; Chase and Chase, 1989, 1992;
Wright, 1994), interpretation of Maya burial programs often lacks the theoretical sophistication of mortuary archaeology in other world areas (e.g.,
Bartel, 1982, Beck, 1995; Chapman et al., 1981; O'Shea, 1984; Tainter,
1978). A comprehensive consideration of status distinctions in diet among
the Maya would require detailed evaluation of these issues and is beyond
the scope of our review, but we briefly summarize findings to date as these
may bear on the collapse.
Social distinctions in diet were first identified at Lamanai. The highstatus Early Classic tomb individuals there consumed the least maize and
may have had privileged access to reef resources (White, 1986; White and
Schwarcz, 1989). Subsequently, social variability in diet has been documented at Copan, Pacbitun, and among the Pasi6n sites. At Copan, Reed
(1992, 1994) notes greater isotopic variability in skeletons interred in architecturally elaborate "high-status" domestic groups than in "low-status"
residences. He interprets this to indicate that high status Copanecos had
access to a broader array of food resources, but it could also be taken to
mean that "high-status" groups contain burials from a broad range of social
strata--including slaves--whose diets differed.
At Pacbitun, settlement and architectural evidence confirms continued
elite activity in the early part of the Terminal Classic Period. Isotopic data
imply social distinctions in diet among different grave types during Late
and Terminal Classic times and suggest that maize was preferentially consumed by elites in the site core at the expense of commoners in the periphery, who ironically must have been directly involved in its cultivation
(White, 1997; White et al., 1993). Unfortunately, it is not possible to compare the extent of status differences in diet between the two periods because of sampling limitations. White argues that increasing divergence in
maize consumption between status groups over time could suggest environmental constraints on maize production as it becomes an increasingly
182
Wright and White
valued social commodity. This may have been occurring at Terminal Classic
Pacbitun.
In contrast, during the Late Classic Period at Dos Pilas and Altar de
Sacrificios, isotopic differentiation in both fi13C and 815N occurs among social subgroups identified through multivariate analyses of mortuary variables. With the exception of 15N enrichment in the highest status group at
Altar, these patterns indicate a more complex pattern of dietary partitioning than that between grave types at Pacbitun. At no site in the Pasi6n
region is fi13C tightly linked with mortuary status in a simple unilineal scale,
indicating that maize cannot be singled out as a socially valued food here.
Indeed, among Terminal Classic Altar and Seibal burials, social heterogeneity in diet is diminished, so competition over resources does not provide
any indication that food sources were limited but, rather, implies a social
transformation that occurred in concert with political disintegration
(Wright, 1994, 1997).
In a broad series of burials from across the lowlands, Gerry (1993)
found that regional stable isotopic paleodietary differences overshadowed
social distinctions. He argues that diet did not vary between status groups
defined by mortuary features, a conclusion contradicted by the studies reviewed above. Social differentiation in this analysis, however, may be obscured by the long chronological span and broad geographic spread of his
burial series. Mortuary symbols are prone to social manipulation and cannot be assumed to have had universal referents over prehistoric Maya time
and space. Indeed, mortuary symbols do not covary uniformly even among
neighboring Pasi6n sites (Wright, 1994), and burial goods exaggerate status
distinctions at some sites in Belize (Chase, 1997).
DISCUSSION AND CONCLUSION
Ecological explanations of the Classic Maya collapse have been examined in light of evidence from human skeletal biology and isotopic dietary
reconstruction. We have questioned a number of the assumptions of these
models, in particular, their occurrence as a pan-Maya phenomenon, and
the necessary inclusion of nutritional and pathology submodels. At the outset of this paper, we raised several concerns about the appropriate use of
analogy from modern agricultural practices, diet, and health to the Prehispanic context. In turn, the evidence from human skeletal biology and isotopic reconstruction reviewed here sheds further doubt on the accuracy of
ecological models of collapse as commonly constituted. Here we have examined paleopathological and paleodietary data largely independently, although these issues are typically subsumed within a single model.
Human Biolo~, in the Classic Maya Collapse
183
Osteological evidence for the nutritional argument is particularly problematic and contradicts the expected trends. In contrast, dietary expectations
are less straightforward. While the isotopic record does not provide consistent support for the broader ecological model, environmental pressures
may have contributed to dietary change at some sites.
We outlined three critical issues for paleopathological data as central
to the integrity of ecological models of collapse. If the nutrition and health
arguments are to be upheld, the skeletal remains must demonstrate (1)
that health was more severely compromised than among other civilizations
that did not collapse, (2) that health deteriorated over the span of Classic
Maya history, and (3) that ancient Maya subsistence choices had a direct
and negative impact on the health of the population.
Although comparison of skeletal data between sites and cultures in
differing epidemiological contexts is fraught with difficulty, consideration
of the data in a global perspective does not support the generally held
assumption that the Maya suffered anomalously high levels of disease.
Comparable levels of anemia, infection, and dental growth disruption can
be found in both urban and less hierarchically organized agricultural societies from a variety of world regions.
At this time, there are no published data which provide unequivocal
support for a change in health burden over Classic Maya history at any
lowland Maya site. Several avenues of investigation do support health
changes between the Classic and the Postclassic periods (White, 1986) and
in concert with the arrival of Spanish conquistadors. Colonial populations
differ from prehistoric ones in terms of stature (Danforth, 1994), infectious
disease (Cohen et al., 1994; White et al., 1994; Wright, 1990), and the timing
of childhood growth arrest (Danforth, 1989), all trends which highlight several problems with the use of modem analogy in interpretation of ancient
Maya health.
The correlation of dietary and pathological data provides some indication that dietary choices had health consequences. This is evident in some
9parallel trends between the expression of anemia and ~13C, but these trends
are not regionally consistent and the role of parasitism in anemic expression
merits further investigation.
Given the frequency with which we are confronted by statements about
the severity of disease among the Maya, we expect that some of our coLleagues will be surprised by the conclusion that the Lowland Maya did not
suffer an anomalous health burden and that health was largely stable over
the Classic Period. Such epidemiological arguments have become almost
axiomatic in discussions of Maya paleoecology, despite the scant evidence
from which they were drawn. Uncritical acceptance of these arguments is
due in part to an understandable tendency to interpret prehistoric health
184
Wright and White
by reference to modern conditions in the tropics. This analogy, though not
inappropriate, suffers from exaggeration of the differences between temperate and tropical epidemiology.
Discussions of disease in the Maya area highlight tropical diseases that
are absent from temperate zones (e.g., Shimkin, 1973). Many of these diseases are familiar to archaeologists as perils of fieldwork. The lowland jungles have been characterized as a "green hell" (Drucker and Fox, 1982),
plagued by extremely abundant pathogens far different from those we encounter in our comfortable temperate homes. Santley et al. (1986) note
that the tropics are home to more species of potentially harmful organisms
than are temperate regions. But is the tropical forest environment especially unhealthy? Rather than a high abundance of noxious pests, the distinguishing feature of tropical forests is their extremely high species
diversity. Hand in hand with the large variety of species present, the abundance of each species is much less than in low-diversity temperate areas.
That is, populations are thinly and patchily distributed (Janzen, 1983). For
pathogens this is an extremely important issue. While a great variety of
parasitic organisms may be found in tropical forests, the risk of contracting
a given infection is proportionately lower. Santley et al. (1986) are correct
in noting that today the burden of illness is greater in the tropics than in
temperate zones. However, in the tropics
the major diseases causing illness.., are frequently not the exotic parasitic diseases
usually associated with tropical medicine, but are primarily bacterial and viral
infectious diseases that once were endemic in industrialized countries but now are
controlled through improvements in immunization, hygiene, nutrition, housing,
water supply, and socioeconomic status . . . . (Walsh, 1990, p. 195).
That is, the perception of tropical forests as disease-ridden is biased by
recent improvements in health care in temperate, developed nations.
We do not mean to imply that the eighth-century Southern Lowlands
were epidemiologically equivalent to a pristine tropical forest. Dramatic
forest clearance would have reduced the abundance of some parasites by
destroying habitats of normal faunal hosts, such as monkeys in the case of
yellow fever. Others would increase with human population density, especially hookworm, intestinal helminths, and roundworms. These may be responsible for the high prevalence of porotic hyperostosis on Maya crania.
As in temperate environments, bacterial and viral infections would have
been dependent on both population density and hygiene.
We concur with Santley et al. (1986) that the prehispanic Americas
were not a disease-free paradise, but neither should the impact of Old
World pathogens on modem health be underestimated. Many of the diseases that may now be contracted in the Maya Lowlands were not present
prehispanically. The most obvious of these is malaria, Plasrnodium vivax,
Human Biology in the Classic Maya Collapse
185
which arrived from Africa in the sixteenth century aboard Spanish galleys
and poses the most omnipresent health hazard in modern Pet6n. Along
with the well-documented diseases smallpox, measles, and typhus, an unidentified number of bacteria and viruses also accompanied the Spaniards
(in both directions of their voyages). We are hard pressed to identify these
today, because most were not medically identified until this century and
therefore lack historical records. Nutrition and health did play an integral
role in Maya culture and paleoecology, but we must beware of laying too
much blame on biological factors for the events of Maya history, unless
rigorous data can be marshaled. At this time a firm connection cannot be
drawn between the paleopathological data and the fate of ancient Maya
cities.
Isotopic paleodietary data are relevant to both health and subsistence
issues. Assuming the central tenet of ecological models--that environmental degradation removes land from agricultural production, thereby reducing the availability of all cultivated foods, especially maize--the dietary
argument can only be upheld by (1) consistent change in isotopic composition of diets into the Terminal Classic Period, (2) changes in the social
distribution of foodstuffs with valued foods increasingly canalized to highstatus individuals, and (3) a correlation among diet and nutritional disease,
growth disruption, and infectious disease.
With respect to 1, as the Classic Period population density rose, the
traditional model argues for increasing reliance on maize, due to its high
productivity, to maintain adequate food supply (Santley, 1990, p. 329). A
concomitant drop in the consumption of wild faunal meat is expected, due
to the diminution of uncultivated forested habitats. This should be shown
by the increasing 613C and decreasing 815N of bone collagen (Wright, 1994,
1996). Alternately, if agricultural failure precludes increased maize production at the expense of other cultigens, and adequate forest or fallow land
remains for the collection of wild resources that had previously not been
intensively exploited, then a decline in 513Cmight signal agricultural stress
(White et aL, 1993; White, 1996). This second scenario requires decoupling
the dietary transition from health problems generally posited to be the
agent of collapse. The possibility that agricultural intensification switched
to highly productive C3 root crops (Bronson, 1966) seems unlikely in view
of the scant paleobotanical evidence for tubers. Moreover, at Lamanai declining caries frequencies correspond to the drop in Classic Period ~13C
(White, 1994), a finding inconsistent with heavy consumption of starchy
roots.
Isotopic dietary data from bone collagen do not provide consistent support for dietary transitions that would corroborate either of these propositions. The current dietary record from 14 regionally diverse sites indicates
186
Wright and White
considerable variation in the amount of maize, C3 plants, and animal foods
consumed by the ancient Maya. During the Terminal Classic, maize consumption neither increases nor declines consistently across the Maya Lowlands. Nor is there support in filSN trends for the proposition that animal
protein became limited. Although a few sites show comparable declines in
Terminal Classic maize consumption, differing sociopolitical and demographic contexts preclude consistent interpretation of the trends. Likewise,
dietary privileges with social status appear to have been independently constituted across the Maya Lowlands. Although maize may have become more
valued in the final occupation at Pacbitun, dietary partitioning is reduced
at Altar and Seibal. As noted above, we have yet little data that adequately
tie pathological conditions to individual diets or confirm a causal relationship between dietary strategy and biological health.
Geographic patterning in paleodiet indicates that environmental factors were important in shaping Maya diets (Gerry, 1993). Sites in Pet6n
show more enriched 813C signatures, indicating greater reliance on maize
and terrestrial herbivores than do riverine sites in Belize, where a broader
spectrum of C3 plants and probably freshwater fauna was available. Lower
environmental diversity in the pine-forested Copfin area compared to the
rain forests of Pet6n and Belize likely accounts for the lower ~ISN and the
inference of greater maize consumption there. Despite these broad ecological differences, the variable trajectories of site-specific diets over time
within a single region appear to have been conditioned more by sociopolitical transitions than environmental constraints.
The absence of consistent trends in paleopathological indicators and
dietary composition compels us to reject ecological models wherein diet
and health stresses are cited as key factors to account for the abandonment
of so many sites in the Southern Maya Lowlands. This is not to say that
environmental and population pressures could not have contributed to sociopolitical instability. Human biological data are best suited to evaluate
long-standing and gradual trends, because skeletal changes better record
chronic than acute illness, and stable isotopes in collagen average diet over
many years. Thus, a dramatic and sudden shift in health--on a scale of 5
years or less--might not be biologically detectable. Moreover, archaeological chronology is insufficiently precise to pinpoint such rapid change in
most aspects of cultural or biological history.
Abrupt abandonment has been documented for several sites in the
Petexbat~n region (Demarest and Houston, 1989, 1990; Demarest et al.,
1992, 1991; Inomata, 1995; Vald6s et al., 1993) but is securely linked to
political rather than ecological factors. Elsewhere, evidence for rapid depopulation following political decay is rare. For instance, a sizable population r e m a i n e d at Altar de Sacrificios after the decline of elite
Human Biology in the Classic Maya Collapse
187
architectural activities (WiUey, 1973). Although Terminal Classic population
did drop substantially in the Central Pet6n, significant continuity in settlement and ceramic systems has been found in the Lake region (D. Rice,
1986; P. Rice, 1986). Depopulation of the Cop~n valley is argued to have
been exceedingly protracted, with dense rural settlement outlasting the political core by several centuries (Webster et al., 1992; Fash and Sharer, 1991;
cf. Braswell, 1992). Moreover, ecological accounts of the collapse typically
argue for a gradual deterioration of the agricultural landscape and of health
over time (Santley et aL, 1986; Culbert, 1988; Willey and Shimkin, 1973).
Recent paleoclimatic work on sediment cores from Lake Chichancanab
in Quintana Roo documents a shift in the stable oxygen isotopic composition (8180) of lake gastropods and ostracods, which is thought to correspond to a period of climatic drying near A.D. 800-1000 (Hodell et al.,
1995). The timing of this event raises the possibility that climatic change
might have played a role in the collapse. Sabloff (1995) suggests that this
drying event might have precipitated rapid environmental degradation or
inhibited recovery of stressed agricultural systems in the most densely populated areas. Health implications of such a shift are unclear. Elimination of
pools of standing water would reduce breeding grounds for some pathogens, but encourage greater utilization of restricted water sources by more
people, elevating the probability of contamination.
It is important to note that these data are from the Northern Lowlands, where water is more critically limited than in the Southern Lowlands,
yet the drying trend is coeval with the growth of Northern cities such as
Sayil, Uxmal, and Chichen Itza. As Hodell and co-workers (1995) state,
the implications of the Chichancanab isotopic data are unknown for the
other parts of the Maya area, and the impact of such a drying trend would
be highly variable across the lowlands given the diversity of microclimatic
patterns. The documented 5180 shift averages about l~
which could
correspond to a relatively slight change in mean temperature or rainfall or
both. However, the complex relationship between 5180 of aquatic fauna
and lake evaporation does not permit easy calculation of the magnitude of
climate change. This shift should not be construed as evidence for "drought"
per se (cf. Sabloff, 1995). Although the evidence for climatic drying is convincing as presented, a consideration of diagenetic alteration of the shell
carbonate--as with isotopic study of bone apatite in the Maya area (Wright
and Schwarcz, 1996)--is critical to evaluation of the results. With the coeval
rise of the Puuc centres, the potentially confounding effects of local deforestation and anthropogenic sedimentation on watertables and evaporation
rates at Lake Chichancanab are also relevant to the isotopic trends. We
would caution archaeologists to await more detailed presentation of these
188
Wright and White
data and confirmation from other parts of the lowlands before embracing
climate change as a trigger for the collapse.
In conclusion, the Maya appear to have experienced a health burden
that is not out of line with that of other complex preindustrial cultures.
There is no evidence for consistent chronological change in either health
stress indicators or diet and few data tie health stress directly to food consumption. Paleodietary reconstructions do not demonstrate a consistent
trend of increasing environmental saturation and degradation but, rather,
implicate both local environmental and political factors in the process of
subsistence change. The implicit coupling of ecology with disease and nutrition in ecological models of the collapse is not upheld by the human
biological data, which were so important to their genesis. Although appealing in simplicity, these models do not account for the local and regional
variability revealed through more recent bioarchaeological investigations
among the Maya. Indeed, the most dramatic change in human biology and
health may have occurred during the Postclassic to Historic transition, as
a consequence of the Spanish Conquest.
Despite the recent upswing in bioarchaeology among the Maya, our
understanding of ancient Maya diet and health is still spotty. At this time,
we do not have data from enough sites with adequate chronological, spatial,
and social representation to evaluate confidently the impact of diet and
health patterns on the evolutionary success of prehistoric Maya peoples
and their cultural institutions. We believe, however, that recent work is beginning to benefit from a more balanced view of the Classic Maya landscape and condition and that bioarchaeology will continue to enrich our
perceptions of the ancient Maya past.
ACKNOWLEDGMENTS
In writing this paper, we have drawn on the work of many osteologists
of the Maya and have attempted to give fair treatment to their work. Jane
Buikstra first urged us to collaborate on a paper of this sort, and her encouragement is greatly appreciated. We thank the many archaeologists with
whom we have worked for their insight and interest in the biological Maya
past, and acknowledge their contribution to our own bioarchaeological
work among the Maya through excavation, financial support, and encouragement. Pat Culbert and Mike Spence kindly read a draft of the manuscript and suggested several improvements, as did two anonymous
reviewers. Our thanks also go to Eric Wright, who created Fig. 1. This paper
was written while L. Wright held a Postdoctoral Fellowship from the Social
Human Biology in the Classic Maya Collapse
189
Sciences and Humanities Research Council of Canada, support which is
gladly acknowledged.
REFERENCES
Adams, R. E. W. (1983). Ancient land use and culture history in the Pasitn River region. In
Vogt, E., Vogt and Leventhal, R. M. (ed.), Prehistoric Settlement Patterns, University of
New Mexico Press, Albuquerque, pp. 319-335.
Adams, R. E. W., Culbert, R. E, Brown, Jr., W. E , Harrison, P. D, and Levi, L. J. (1990).
Rebuttal to Pope and Dahlin. Journal of Field Archaeology 17: 241-244.
Aksoy, M., (~amli, N., and Erdem, S. (1966). Roentigenographic bone changes in chronic iron
deficiency anemia, a study of twelve patients. Blood 27: 677-686.
Ambrose, S. H. (1993). Isotopic analysis of paleodiets: Methodological and interpretive
considerations. In Sandford, M. K. (ed.), Investigations of Ancient Human T~ssue:Chemical
Analyses in Anthropology. Gordon and Breach Science, Amsterdam, pp. 59-130.
Ambrose, S. H., and Norr, L. (1993). Experimental evidence for the relationship of the carbon
isotope ratios of whole diet and dietary protein to those of bone collagen and carbonate.
In Lambert, J., and Grupe, G. (eds.), Prehistoric Human Bone: Archaeology at the
Molecular Level, Springer-Verlag, Berlin, pp. 1-37.
Armelagos, G. J. (1968). Paleopathology of Three Archaeological Populations from Sudanese
Nubia, Unpublished Ph.D. dissertation, University of Colorado, Boulder.
Ashmore, W. (1981). Lowland Maya Settlement Patterns, University of New Mexico Press,
Albuquerque.
Atran, S. (I993). ltza Maya tropical agroforestry. Current Anthropology 34: 633-700.
Barrera, A., Gtmez-Pompa, A., and V'~zquez-Yanes, C. (1977). El manejo de las selvas pot
los Mayas: Sus implicaciones silvieolas y agricolas. Bittiea (Mexico) 2: 47-61.
Barrel, B. (1982). A historical review of ethnological and archaeological analyses of mortuary
practice. Journal of Anthropological Archaeology I: 32-58.
Beck, J. W., and Barrett-Connor, E. (1971). Medical Parasitology, C. V.. Mosby, St. Louis, MO.
Beck, L. A. (ed.).(1995).RegionaIApproaches to Mortuary Analysis, Plenum Press,New York.
Beh~r, M. (1977). Protein-caloriedeficitsin developing countries.Annals of the New York
Academy of Sciences 31111:176-187.
Bocquet-Appel, L P., and Masset, C. (1982). Farewell to paleodemography. Journal of Human
Evolution 11: 321-333.
Boequet-Appel, J. P., and Masset, C. (1985). Paleodemography: Resurrection or ghost? Journal
of Human Evolution 14: 107-111.
Bogin, B. (1988). Patterns of Human Growth, Cambridge University Press, Cambridge.
Bongaarts, J., and Delgado, H. (1977). Effects of nutritional status on fertility in rural
Guatemala, Center for Policy Studies, Working Papers, No. 7. Population Council, New
York.
Brasweli, G. E. (1992). Obsidian-hydration dating, the Coner Phase, and revisionist chronology
at Copan, Honduras. Latin American Antiquity 3: 130-147.
Brenner, M., Leyden, B., and Binford, M. W. (1990). Recent sedimentary histories of shallow
lakes in the Guatemalan savannas. Journal of Paleolimnology 4: 239-252.
Bressani, R., and Scrimshaw, N. (1958). Effect of lime treatment on in vitro availability of
essential amino acids and solubility of protein fractions in corn. Agricultural and Food
Chemistry 6: 774-778.
Bressani, R., Paz y Paz, R., and Scrimshaw, N. S. (1958). Chemical changes in corn during
preparation of tortillas. Agricultural and Food Chemistry 6: 770-774.
Bronson, B. (1966). Roots and the subsistence of the ancient Maya. Southwestern Journal of
Anthropology 22: 251-279.
190
Wright and White
Buikstra, J. E., and Cook, D. C. (1980). Palaeopathology: An American account. Annual
Review of Anthropology 9: 433-470.
Buikstra, J. E., and Konigsberg, L. W. (1985). Paleodemography: Critiques and controversies.
American Anthropologist 87: 316--333.
Burgess, S. D. (1996). Patterns of anemia in three Late Intermediate populations from the
south coast of Peru. Journal of Steward Anthropology (in press).
Burko, H., Mellins, H. Z., and Watson, J. (1961). Skull changes in iron deficiency anemia
simulating congenital hemolytic anemia. American Journal of Roentgenology 86: 447.452.
Carlson, D. S., Armelagos, G. J., and Van Gerven, D. (1974). Factors affecting the etiology
of cribra orbitalia in prehistoric Nubia. Journal of Human Evolution 3: 405--410.
Chapman, R., Kinnes, I., and Randsborg, K. (1981). The Archaeology of Death, Cambridge
University Press, Cambridge.
Chase, A. E, and Chase, D. Z. (1989). Maya veneration of the dead at Caracol, Belize. In
Robertson, M. G. (ed.), Seventh Mesa Redonda de Palenque, 1989. Vol. VIII,
Pre-Columbian Art Research Institute, San Francisco (in press).
Chase, D. (1997). Southern Lowland Maya archaeology and human skeletal remains:
Interpretations from Caracol (Belize), Tayasal (Guatemala), and Santa Rita Corozal
(Belize). In Whittington, S., and Reed, D. (eds.), Bones of the Ancestors: Recent Studies
of Ancient Maya Skeletons, Smithsonian Institution Press, Washington, DC.
Chase, D. Z., and Chase, A. E (eds.). (1992). Mesoamerican Elites: An Archaeological
Assessment, University of Oklahoma Press, Norman.
Cohen, M. N. (1994). The osteological paradox reconsidered. Current Anthropology 35:
629-631.
Cohen, M. N., and Armelagos, G. J. (1984). Paleopathology at the origins of agriculture:
Editors' summation. In Cohen, M. N., and Armelagos, G. J. (eds.), Paleopathology at the
Origins of Agriculture, Academic Press, New York. pp. 585-601.
Cohen, M. N., O'Connor, K., Danforth, M., Jacobi, K., and Armstrong, C. (1994). Health
and death at Tipu. In Larsen, C. S., and Milner, G. (eds.), In the Wake of Contact:
Biological Responses to Conquest, Wiley-Liss, New York, pp. 121-133.
Commission on Oral Health, R. a. E. (1982). An epidemiological index of developmental
defects of dental enamel (DDE Index). International Dental Journal 32: 159-167.
Cook, D. C. (1976). Pathologic States and Disease Process in Illinois Woodland Populations: An
Epidemiologic Approach, Unpublished Ph.D. dissertation, University of Chicago, Chicago.
Cook, D. C. (1981). Mortality, age structure and status in the interpretation of stress indicators
in prehistoric skeletons: A dental example from the Lower Illinois Valley. In Chapman,
R. W, and Randsborg, K. R. (eds.), The Archaeology of Death, University Press,
Cambridge, pp. 133-144.
Corruccini, R. S., Handler, J. S., and Jacobi, K. E (1985). Chronological distribution of enamel
hypoplasias and weaning in a Caribbean slave population. Human Biology 57: 699-711.
Coyston, S. (1994). An Application of Carbon Isotopic Ana~sis of Bone Apatite to the Study of
Maya Diets and Subsistence at Pacbitun and Lamanai, Belize, Unpublished M.A. thesis,
Department of Anthropology, Trent University.
Culbert, T. E (Ed.). (1973). The Classic Maya Collapse, University of New Mexico Press,
Albuquerque.
Culbert, T. P. (1988). The collapse of Classic Maya civilization. In Yoffee, N., and Cowgill, G.
L. (eds.), The Collapse of Ancient States and Civilizations, University of Arizona Press,
Tucson, pp. 69-101.
Culbert, T. E (ed.). (1991). Classic Maya Political History: Hieroglyphic and Archaeological
Evidence, Cambridge University Press, Cambridge.
Culbert, T. P., and Rice, D. S. (1990). Precolumbian Population History in the Maya Lowlands,
University of New Mexico Press, Albuquerque.
Danforth, M. E. (1989). A Comparison of Childhood Health Patterns in the Late Classic and
Colonial Maya using Enamel Microdefects, Unpublished Ph,D. dissertation, Indiana
University.
Danforth, M. E. (1994). Stature change in prehistoric Maya of the Southern Lowlands. Latin
American Antiquity 5: 206-211.
Human Biology in the Classic Maya Collapse
191
Danforth, M. E. (1996). Childhood health patterns in the Late Classic Maya: Evidence from
enamel microdefects. In Whittington, S., and Reed, D. (eds.), Bones of the Ancestors:
Recent Studies of Ancient Maya Skeletons, Smithsonian Institution Press, Washington, DC
(in press).
Danforth, M. E., Herndon, K. S., and Propst, K. B. (1993). A preliminary study of patterns
of replication in scoring linear enamel hypoplasias. International Journal of
Osteoarchaeology 3: 297-302.
Deevey, E. S., Rice, D. S., Rice, P. M., Vaughan, H. H., Brenner, M., and Flannery, M. S.
(1979). Mayan urbanism: Impact on a tropical karst environment. Science 206: 298-306.
Demarest, A. A. (1992). Ideology in Ancient Maya cultural evolution: The dynamics of galactic
polities. In Demarest, A. A., and Conrad, G. (eds.), Ideology and PreColumbian
Civilizations, School of American Research Seminar, School of American Research Press,
Santa Fe, NM, pp. 135-157.
Demarest, A. A. (1993). War, peace, and the collapse of a native American civilization. In
Gregor, T. (ed.), What We Know About Peace? H. E Guggenheim Foundation, New York
(in press).
Demarest, A., and Houston, S. (1989). Proyecto Arqueol6gico Regional Petexbattin. Informe
Preliminar #1. Primera Temporada, Vanderbilt University, Nashville, "IN.
Demarest, A. A., and Houston, S. D. (1990). Proyecto Arqueol6gico Regional Petexbattln.
Informe Preliminar #2. Segunda Temporada, Vanderbilt University, Nashville, "IN.
Demarest, A. A., Inomata, T., Escobedo, H., and Palka, J. (1991). Proyecto Arqueol6gico
Regional Petexbatlln. lnforme Preliminar #3. Tercera Temporada. Vanderbilt University,
Nashville, "Fig.
Demarest, A. A., Inomata, T., and Escobedo, H. (1992). Proyecto Arqueol6gico Regional
Petexbattin. Informe Preliminar #4. Cuarta Temporada. Vanderbilt University, Nashville,
TN.
DeNiro, M. J. (1987). Stable isotopy and archaeology. American Scientist 75: 182-191.
DeNiro, M. J., and Epstein, S. (1981). Influence of diet on the distribution of nitrogen isotopes
in animals. Geochimica et Cosmochimica Acta 45: 341-351.
Drucker, E, and Fox, J. W. (1982). Swidden didn' make all that midden: The search for Ancient
Mayan agronomics. Journal of Anthropological Research 38: 179-193.
Dunning, N. P., and Beach, "E (1994). Soil erosion, slope management, and ancient terracing
in the Maya Lowlands. Latin American Antiquity 5: 51-69.
Early, J. D. (1982). The Demographic Structure and Evolution of a Peasant System: The
Guatemalan Population, University Presses of Florida, Boca Raton.
EI-Najjar, M. Y. (1977), Porotic Hyperostosis in North America: A Theory. In Cockburn, E.
(ed.), Porotic Hyperostosis: An Enquiry, Monograph No. 2. Paleopathology Association,
Detroit, MI, pp. 9-10.
EI-Najjar, M. Y., Desanti, M. V., and Ozebck, L (1978). Prevalence and possible etiology of
dental enamel hypoplasia. American Journal of Physical Anthropology 48: 185-192.
EI-Najjar, M. Y., Ryan, D. J., Turner, C. G., II, and Lozoff, B. (1976). The etiology of porotic
hyperostosis among the prehistoric and historic Anasazi Indians of the Southwestern
United States. American Journal of Physical Anthropology 42: 477--488.
Fash, W. L. (1991). Scribes, Warriors and Kings. The City of Copdn and the Ancient Maya,
Thames and Hudson, New York.
Fash, W. L. (1994). Changing perspectives on Maya civilization. Annual Review of Anthropology
23: 181-208.
Fash, W. L., and Sharer, R. J. (1991). Sociopolitical developments and methodological issues
at Copan, Honduras: A conjuetive perspective. Latin American Antiquity 2: 166-187.
Faulhauber, J. (1970). Anthropometry of living indians. In Stewart, T D. (ed.), Handbook of
Middle American lnd/ans, Vol. 9. Physical Anthropology. University of Texas Press, Austin,
pp. 105-147.
Fedick, S. L., and Ford, A. (1990). The prehistoric agricultural landscape of the central Maya
lowlands: An examination of local variability in a regional context. World Archaeology 22:
18-33.
192
Wright and White
Freidel, D. A. (1986). Maya warfare: An example of peer polity interaction. In Cherry, C. R.
a. J. (eds.), Peer Polity Interaction and Sociopolitical Change, Cambridge University Press,
London, pp. 93-108.
Fried, M. H. (1967). The Evolution of Political Society: An Essay in Political Anthropology.
Random House, New York.
Genov6s, S. C. (1970). Anthropometry of Late Prehistoric human remains. In Stewart, T D.
(ed.), Handbook of Middle American Indians, Vol. 9. Physical Anthropology, University
of Texas Press, Austin, pp. 35-69.
Gerry, J. E (1993). Diet and Status Among the Classic Maya: An Isotopic Perspective,
Unpublished Ph.D. dissertation, Harvard University, Cambridge, MA.
Gerry, J. E, and Krueger, H. W. (1997). Regional Diversity in Classic Maya Diets. In
Whittington, S., and Reed, D. (eds.), Bones of the Ancestors: Recent Studies of Ancient
Maya Skeletons, Smithsonian Institution Press, Washington, DC (in press).
Goff, C. W. (1953). New evidence of Pre-Columbian bone syphilis in Guatemala. In Woodbury,
R. B., and Trik, A. S. (eds.), The Ruins of Zaculet~ Guatemala. VoL 1, United Fruit
Company, pp. 312-319.
Goodman, A. (1993). On the interpretation of health from skeletal remains. Current
Anthropology 34: 281-288.
Goodman, A. H., and Armelagos, G. J. (1985a). The chronological distribution of enamel
hypoplasia in human permanent incisor and canine teeth. Archives of Oral Biology 30:
503-507.
Goodman, A. H., and Armelagos, G. J. (1985b). Factors affecting the distribution of enamel
hypoplasias within the human permanent dentition. American Journa[ of Physical
Anthropology 68: 479-493.
Goodman, A. H., and Armelagos, G. J. (1988). Childhood stress and decreased longevity in
a prehistoric population. American Anthropologist 90: 936--944.
Goodman, A. H., and Rose, J. C. (1990). Assessment of systemic physiological perturbations
from dental enamel hypoplasias and associated histological structures. Yearbook of Physical
Anthropology 33: 59-110.
Grauer, A. L. (1993). Patterns of anemia and infection from Medieval York, England.
American Journal of Physical Anthropology 91: 203-213.
Greenfield, G. B., and Schorsch, H. A. (1967). The various roentgen appearances of
pulmonary hypertrophic osteoarthropathy. American Journal of Roentgenology 101:
927-93L
Hamblin, N. (1984). Animal Use by the Cozumel Maya, University of Arizona Press, Tucson.
Harrison, E D. (1977). The rise of the bajos and the fall of the Maya. In Hammond, N.
(ed.), Social Process in Maya Prehistory:Studies in Memory of Sir Eric Thompson, Academic
Press, London, pp. 469-508.
Harrison, P. D. (1990)o The revolution in ancient Maya subsistence. In Clancy, E S., and
Harrison, E D. (eds.), Vision and Revision in Maya Studies, University of New Mexico
Press, Albuquerque, pp. 99-113.
Harrison, E D., and Turner, B. L., II (1978). Pre-Hispanic Maya Agriculture, University of New
Mexico Press, Albuquerque.
Haviland, W. A. (1967). Stature at Tikal, Guatemala: Implications for Classic Maya
demography and social organization. American Antiquity 32: 316--325.
Healy, P E, Lambert, J. D. H., Arnason, J. T., and Hebda, R. J. (1983). Caracol, Belize:
Evidence of ancient Maya agricultural terraces. Journal of Field Archaeology 10: 397--410.
Hodell, D. A., Curtis, J. H., and Brenner, M. (1995). Possible role of climate in the collapse
of Classic Maya civilization. Nature 375: 391-394.
Hooton, E. A. (1940). Skeletons from the eenote of sacrifice at Chichen ItS. In Hay, C. L.
(ed.), The Maya and Their Neighbors, Appleton-Century, New York, pp. 272-280.
Home, E D, (1985). A review of the evidence of human endoparasitism in the pre-Columbian
New World through the study of coprolites. Journal of Archaeological Science 12: 299-310.
Hutchinson, D. L., and Larsen, C. S. (1988). Determination of stress episode duration from
linear enamel hypoplasias: A ease study from St. Catherines Island, Georgia. Human
Biology 60: 93-110.
Human Biology in the Classic Maya Collapse
193
INCAP (1961). Food Composition Tablefor Use in Latin America, National Institutes of Health,
Bethesda, MD.
INE (1993). Estadisticas Vitales. Defunciones Generales, 1986-90, Vol. 2, Instituto Nacional de
Estadistica, Guatemala.
Inomata, T. (1995). Archaeological Investigations at the Fortified Center of Aguateca, El Pet#n,
Guatemala: Implications for the Study of the Classic Maya Collapse, Unpublished Ph.D.
dissertation, Vanderbilt University, Nashville, TN.
Jackes, M. (1993). On paradox and osteology. Current Anthropology 34: 434-438.
Janzen, D. H. (1983). Food webs: Who eats what, why, how, and with what effects in a tropical
forest. In Golley, E B. (ed.), Tropical Rain Forest Ecosystems. Structure and Function.
Ecosystems of the World, 14A, Elsevier Scientific, Amsterdam. pp. 167-182.
Johnston, K. (1994). The "Invisible" Maya: Late Classic Minimally-Platformed Residential
Settlement at Itz6n, Petdn, Guatemala. Unpublished Ph.D. dissertation, Yale University,
New Haven, C'E
Jones, G. D. (1989). Maya Resistance to Spanish Rule: Time and History on a Colonial Frontier,
University of New Mexico Press, Albuquerque.
Katz, S. H., Hediger, M. L., and Vaileroy, L. A. (1974). Traditional maize processing techniques
in the New World. Science 184: 765-773.
Keegan, W. E, and DeNiro, M. J. (1988). Stable carbon- and nitrogen-isotope ratios of bone
collagen used to study coral-reef and terrestrial components of prehistoric Bahamian diet.
American Antiquity 53: 320-336.
Kennedy, G. E. (1983). Skeletal remains from Sarteneja, Belize. In Sidrys, R. V.. (ed.),
Archaeological Excavations in Northern Belize, CentralAmerica, Monograph XVII. Institute
of Archaeology, University of California, Los Angeles, pp. 353-372.
Krueger, H. W., and Sullivan, C. H. (1984). Models for carbon isotope fractionation between
diet and bone. In Turnland, J. E, and Johnson, P. E. (eds.), Stable Isotopes in Nutrition.
ACS Symposium, American Chemical Society, Washington DC, pp. 205-220.
Lallo, J. W., Armelagos, G. J., and Mensforth, R. P. (1977). The role of diet, disease, and
physiology in the origin of porotic hyperostnsis. Human Biology 49: 471-483.
Lange, E W. (1971). Marine resources: A viable subsistence alternative for the prehistoric
lowland Maya. American Anthropologist 73: 619-639.
Lee-Thorp, J. A., Scaly, J. C., and van der Merwe, N. J. (1989). Stable carbon isotope ratio
differences between bone collagen and bone apatite, and their relationship to diet. Journal
of Archaeological Science 16: 585-599.
Lentz, D. L. (1991). Maya diets of the rich and poor: Paleoethnobotanical evidence from
Copan. Latin American Antiquity 2: 269-287.
Lowe, J. W. G. (1985). Dynamics of Apocalypse: A Systems Simulation of the Classic Maya
Collapse, University of New Mexico Press, Albuquerque.
Mfirquez Morfin, L., Peraza, M. E., Gamboa, J., and Miranda, T. (1982). Playa del Carmen:
Una Poblaci6n de la Costa Oriental en el Postcldsico (Un Estudio Osteologico), Colecci6n
Cientifica, 119, INAH, Mexico.
Martorell, R. (1992). Overview of long-term nutrition intervention studies in Guatemala,
1968-1989. Food and Nutrition Bulletin 14: 270-277.
Mata, L., and Salas, R (1984). Mucosal infections and malnutrition. In Ogra, R L. (ed.),
Neonatal Infections. Nutritional and Immunologic Interactions, Grune and Stratton,
Orlando, FL, pp. 299-313.
McAnany, P. A. (1995). Living with the Ancestors: Kinship and Kingship in Ancient Maya Society,
University of Texas Press, Austin.
Mensforth, R. E, Lovejoy, C. O., LaUo, J. W., and Armelagos, G. J. (1978). The role of
constitutional factors, diet, and infectious disease in the etiology of porotic hyperostosis
and periosteal reactions in prehistoric infants and children. Medical Anthropology 2: 1-57.
Miksicek, C. H. (1983). Macrofloral remains of the PuUtrouser area: Settlements and fields.
In Turner, B. L., II, and Harrison, P. D. (exls.), Pulltrouser Swamp: Ancient Maya Habitat,
Agriculture, and Settlement in Northern Belize, University of Texas Press, Austin, pp.
94-104.
194
Wright and White
Miller, M. E. (1993). On the eve of the collapse: Maya art of the eighth century. In Sabloff,
J. A., and Henderson, J. S. (eds.), Lowland Maya Civilization in the Eighth Century AoD,
Dumbarton Oaks, Washington, DC, pp. 355--414~
Moseley, J. E. (1965). The paleopathologic riddle of "symmetrical osteoporosis." American
Journal of Roentgenology and Radium Therapy 95: 135-142.
Nations, J. D., and Nigh, R. B. (1980). The evolutionary potential of Lacandon Maya
sustained-yield tropical forest agriculture. Journal of Anthropological Research 36: 1-30.
Nickens, E R. (1976). Stature reduction as an adaptive response to food production in
Mesoamerica. Journal of Archaeological Science 3: 31--41.
Norr, L. C. (1991). Nutritional Consequences of Prehistoric Subsistence Strategies in Lower
Central America, U n p u b l i s h e d Ph.D. D i s s e r t a t i o n , University of lllinois at
Urbana-Champaign, Urbana.
O'Leary, M. H. (1988). Carbon isotopes in photosynthesis. Bioscience 38: 328-336.
O'Shea, J. M. (1984). Mortuary Variability, Academic Press, New York.
Ortner, D. J., and Putschar, W G. (1981). Identification of Pathological Conditions in Human
Skeletal Remains, Smithsonian Contributions to Anthropology, No. 28, Smithsonian
Institution, Washington, DC.
Paine, R. R. (1992). Population Dynamics at Copan, Honduras, AD 450-1250: A Study in
Archaeological Demography, Unpublished Ph.D. Dissertation, Pennsylvania State
University, University Park, PA.
Palkovich, A. M. (1987). Endemic disease patterns in paleopathology: porotic hyperostosis.
American Journal of Physical Anthropology 74: 527-537.
Pendergast, D. M. (1986). Stability through change: Lamanai, Belize, from the ninth to the
seventeenth century. In Sabloff, J., and Andrews, E. W., V (eds.), Late Lowland Maya
Civilization: Classic to Postclassic, University of New Mexico Press, Albuquerque, pp.
223-249.
Perera, V. (1993). Unfinished Conquest. The Guatemalan Tragedy, University of California Press,
Berkeley.
Perzigian, A. J., Tench, P. A., and Braun, D. J. (1984). Prehistoric health in the Ohio River
Valley. In Cohen, M. N., and Armelagos, G. J. (eds.), Palaeopathology at the Origins of
Agriculture, Academic Press, New York, pp. 347-366.
POhL M. (1990). The ethnozoology of the Maya: Faunal remains from five sites in Peten,
Guatemala. In Willey, G. R. (ed.), Excavations at Seibal, Peabody Museum of Archaeology
and Ethnology, Memoirs, Vol. 17(2), Harvard University, Cambridge, MA, pp. 143-174.
Pope, K. O., and Dahlin, B, H. (1989). Ancient Maya wetland agriculture: New insights from
ecological and remote sensing research. Journal of Field Archaeology 16: 87-106.
Powell, M. L. (1988). Status and Health in Prehiatory:A Case Study of the Moundville Chiefdom,
Smithsonian Institution Press, Washington, DC.
Powell, M. L. (1991). Endemic treponematosis and tuberculosis in the prehistoric southeastern
United States: Biological costs of chronic endemic disease. In Ortner, D. J., and
Aufderheide, A. C. (eds.), Human Paleopathology: Current Syntheses and Future Options,
Smithsonian Institution Press, Washington, DC, pp. 173-180.
Ragsdale, B. D., Madeweil, J. E., and Sweet, D. E. (1981). Radiologic and pathologic analysis
of solitary bone lesions. II. Periosteal reactions. Radioiogic Clinics of North America 19:
749-783.
Reed, D. M. (1992). Ancient Copan diet through stable carbon and nitrogen isotopic analysis.
Paper presented to the annual meeting of the Society for American Archaeology,
Pittsburgh.
Reed, D. M. (1994). Ancient Maya diet at Cop-in, Honduras, as determined through the
analysis of stable carbon and nitrogen isotopes. In Sobolik, K. D. (ed.), Paleonutrition:
The Diet and Health of Prehistoric Americans, Occasional Papers Series, Center for
Archaeological Investigations, Southern Illinois University, Carbondale, pp. 210-221.
Reinhard, K. J. (1988). Cultural ecology of prehistoric parasitims on the Colorado Plateau as
evidenced by coprology. American Journal of Physical Anthropology 77: 355-366.
Reinhard, K. J. (1990). Archaeoparasitology in North America. American Journal of Physical
Anthropology 82: 145-163.
Human Biology in the Classic Maya Collapse
195
Resnick, E., and Niwayama, G. (1981). Diagnosis of Bone and Joint Disorders, Saunders,
Philadelphia.
Rice, D. S. (1986). The Pet6n Postclassic: A settlement perspective. In Sabloff, J. A., and
Andrews, E. W., V (eds.), Late Lowland Maya Civilization: Classic to Postclassic, University
of New Mexico Press, Albuquerque, pp. 301-344.
Rice, D. S. (1993). Eighth-century physical geography, environment, and natural resources in
the Maya Lowlands. In Sabloff, J. A., and Henderson, J. S. (eds.), Lowland Maya
CMlization in the Eighth Century A.D., Dumbarton Oaks, Washington, DC, pp. 11--63.
Rice, P. M. (1986). The Pet6n Postclassic: Perspectives from the Central P.et6n Lakes. In
Sabloff, J. A., and Andrews, E. W., V (eds.), Late Lowland Maya Civ'dization: Classic to
Postclassic. University of New Mexico Press, Albuquerque. pp., 251-299.
Rice, D. S., and Rice, P. M. (1984). Lessons from the Maya. Latin American Antiquity 19:
7-34.
Rice, D. S., and Rice, P. M. (1994). Looking back: The Central Pet6n Maya "collapse" from
the perspective of Postclassic data. Paper presented to the annual meeting of the
American Anthropological Association, Atlanta, GA.
Rose, J. C., Armelagos, G. J., and LaUo, J. W. (1978). Histological enamel indicator of
childhood stress in prehistoric skeletal samples. American Journal of Physical Anthropology
49: 511-516.
Roys, R. L. (1943). The Indian Baclq~und of Colonial Yucatan, Publication 548, Carnegie
Institution of Washington, Washington, DC.
Sabloff, J. A. (1995). Drought and decline. Nature 375: 357.
Sanders, W. T (1973). The cultural ecology of the Lowland Maya: A reevaluation. In Culbert,
T P. (ed.), The Class/c Maya Co//apse, University of New Mexico Press, Albuquerque, pp.
325-366.
Santley, R. S. (1990). Demographic archaeology in the Maya Lowlands. In Culbert, T P., and
Rice, D. S. (eds), Preco/umb/an Popu/at/on/-Ftstoty in the Maya Low/ands, University of
New Mexico Press, Albuquerque, pp. 325-343.
Sanfley, S. R., KiUion, T W., and Lycett, M. T (1986). On the Maya collapse. Journal of
AnthmlaTiogical Research 42: 123-159.
Sattenspiel, L., and Harpending, H. (1983). Stable populations and skeletal age. Amer/can
Ant/qu/ty 48: 489-498.
Saul, E P. (1972). The Human Skeletal Remains of Altar de ~ :
An Osteobioya~ic
Analysis, Peabody Museum of Archaeology and Ethnology, Papers, Vol. 63, No. 2, Harvard
Unive~ty Press, Cambridge, MA.
Saul, E P. (1973). Disease in the Maya area: The pre-Columbian evidence. In Culbert, T P.
(ed.), The C/a~/c Maya ~ ,
University of New Mexico Press, Albuquerque, pp.
301-324.
Saul, E P. (1975). Human remains from Lubanntun. In Hammond, N. (ed.), Lubaan/un,
Peabody Museum of Archaeology and Ethnohistory, Monograph No. 2, Harvard
University, Cambridge, MA, pp. 389-410.
Saul, E P. (1977). The paleopathology of anemia in Mexico and Guatemala. In Cockburn, E.
(ed.), Porotic ~ :
An Enqui~, Monograph No. 2, Paleopathology ~ t i o n ,
Detroit, ML pp. 10--15.
Saul, E P. (1982). The human skeletal remains from "lhncah, Mexico. In Miller, A. G. (ed.),
On the Edfr of the Sea: Mural Painting at Tancah.Thlum, Quintana Roo, Mexico,
Dumbarton Oak& Washington, DC, pp. 115-127.
Saul, E P., and Saul, J. M. (1991). The Preclassir population of C.aello. In Hammond, N.
(ed.), Cueilo: An Early Maya Community in Belize, Cambridge University Press,
Cambridge, MA, pp. 136-158.
Schoeninger, M. J. (1985). ltephic level effects on IsN/14N and 13C./12Cratio, in bone collagen
and strontium levels in bone mineral. Jouma/of Human Evo/u//on 14: 515--525.
Schwartz, H. E, and Se,hoeninger, M. J. (1991). Stable isotope analyses in human nutritional
ecology. YeadaTokoJfPhys/ca/Anduvpeio~ 34: 28.3-321.
Schwartz, N. B. (1990). Forest $o,:iay: A $ocla/HLUo,y of At/n, O~_~c.-?m~, University of
Pennsylvania Pre~ Philadelphia.
196
Wright and White
Scrimshaw, N. S., Taylor, C. E, and Gordon, J. E. (1968). Interactions of Nutrition and
Infection. Monograph Series, No. 57, World Health Organization, Geneva.
Scrimshaw, N. S., and Tejada, C. (1970). Pathology of living Indians as seen in Guatemala.
In Stewart, T. D. (ed.), Handbook of Middle American Indians, Vol. 9. Physical
Anthropology, University of Texas Press, Austin, pp. 203--225.
Sharer, R. J. (1994). The Ancient Maya (5th ed.), Stanford University Press, Stanford, CA.
Shattuck, G. C. (1938). A Medical Survey of the Republic of Guatemala, Publication 499,
Carnegie Institution of Washington, "vVashington,DC.
Shimkin, D. B. (1973). Models for the downfall: Some ecological and culture-historical
considerations. In Culbert, T. P (ed.), The Classic Maya Collapse, University of New
Mexico Press, Albuquerque, pp. 269-300.
Sibri~in, R., and Elston, R. C. (1990). Reciprocal causal influences among malnutrition, growth
retardation, and diarrhea in preschool children. American Journal of Human Biolo~ 2:
235-243.
Siemens, A. H., and Puleston, D. E. (1972). Ridged fields and associated features in southern
Campeche: New perspectives on the Lowland Maya. American Antiquity 37: 228-239.
Smith, P, Bar-Yosef, O., and Sillen, A. (1984). Archaeological and skeletal evidence for dietary
change during the late Pleistocene/Early Holocene in the Levant. In Cohen, M. N., and
Armelagos, G. J. (eds.), Paleopathology at the Origins of Agriculture, Academic Press, New
York, pp. 101-127.
Spinden, H. J. (1928). The Ancient Civilizations of Mexico and Central America, Handbook
Series, No. 3, American Museum of Natural History, New York.
Steggerda, M. (1941). Maya Indians of Yucata, Publication 531, Carnegie Institution of
Washington, Washington, DC.
Stewart, T D. (1949). Notas sobre esqueletos humanos prehistoricos hallados en Guatemala.
Antropologla e Historla de Guatemala 1: 23-34.
Stewart, T. D. (1953). Skeletal remains from Zaculeu, Guatemala. In Woodbury, R. B., and
Trik, A. S. (eds.), The Ruins of Zaculeu, Guatemala, VoL 1, United Fruit Company, pp.
295-311.
StoU, D. (1993). Between Two Armies in the Ixil Towns of Guatemala, Columbia University
Press, New York.
Storey, R. (1992a). The children of Copan: Issues in paleopathology and paleodemography.
Ancient Mesoamerica 3: 161-167.
Storey, R. (199213). Patterns of susceptibility to dental defects in the deciduous dentition of
a precolumbian skeletal population. In Goodman, A. L., and C.apasso, L. L. (eds.), Recent
Conuibutions to the Study of Enamel Developmental Defects, Journal of Paleopathoiogy,
Monographie Publications, 2, Edigrafital Teramo, Chieti, Italy, pp. 171-183.
Stuart-Macadam, P. (1985). Porotie hypernstosis: Representative of a childhood condition.
American Journal of Phys/ca/Anthropo/ogy 66: 391-398.
Stuart-Ma~,zl__nm,P. (1987). Porotic hyperostos~ New evidence to support the anemia theory.
American Journal of Physical Anthropoi~ 74: 521-526.
Stuart-Macadam, P. (1989). Porotic hyperostmis: Relationship between orbital and vault
lesions. American Journal of Physical Anthropok~ 80:. 187-193.
Stuart-Macadam, E (1992). Porotic hyperostosis: A new perspective. American Journal of
PhysicalAnthropolo~ 87: 39-47.
Suhler, C., and Freidel, D. (1992), 7/zr Sr F-oundatkm Yaxuna Project. F'ma/Report of the
1992 lrwJd Season, Southern Methodist University, Dallas.
Suzuki, T. (1991). Paleopathoiogical study on infectious diseases in Japan. In Ortner, D. J.,
and Auferheide, A. C. (ede.), Human Palwpathoiou: Current Syntheses and Future
Opt/ons, Smithsonian Institution Prem, Waahin~on, DC,, pp. 128-139.
'l]finter, J. A. (1978). Mortuaff practices and the study of prehistoric social systems. In Schiffer,
M. B. (ed.), Advances in Archaeological Method and Theory. 1, Academic Press, New York,
pp. 105-141.
Tllinter, J. A. (1988). The Collapse of Complex Societies, Cambridge University Press,
Cambridge, MA.
Human Biology in the Classic Maya Collapse
197
Tieszen, L L., and Fagre, T (1993). Effect of diet quality and composition on the isotopic
composition of respiratory CO2, bone collagen, bioapatite, and soft tissues. In Lambert,
J. B., and Grupe, G. (eds.), Prehistoric Human Bone: Archaeology at the Molecular Level,
Springer-Verlag, Berlin, pp. 121-155.
Turner, B. L., II (1974). Prehistoric intensive agriculture in the Maya lowlands. Science 185:
118-124.
Turner, B. L., II (1990). The rise and fall of population and agriculture in the Central Maya
Lowlands: 300 B.C. to Present. In Newman, L. E (ed.), Hunger in History: Food Shortage,
Poverty, and Deprivation, Basil Blackwell, Oxford, pp. 178-211.
Tykot, R. H., van der Merwe, N. J., and Hammond, N. (1996). Stable isotope analysis of bone
collagen, bone apatite, and tooth enamel in the reconstruction of human diet: A case
study from Cuello, Belize. In Orna, M. V. (ed.), Archaeological Chemistry V, American
Chemical Society, V~shington, DC.
Ubelaker, D. H. (1992). Porotic hyperostosis in Prehistoric Ecuador. In Stuart-Macadam, P.,
and Kent, S. (eds.), Diet, Demography and Disease: Changing Perspectives on Anemia,
Aldine de Gruyter, New York.
Vald6s, J. A., Foias, A., Inomata, Z, Escobedo, H., and Demarest, A. A. (1993). Proyecto
Arqueol6gico Regional PetexbatKm. lnforrne Preliminar #5. Quinta Temporada, Vanderbilt
University, Nashville, TN.
van der Merwe, N. J. (1982). Carbon isotopes, photosynthesis, and archaeology. American
Scientist 70: 596-606.
Van Gerven, D. P., and Armelagos, G. (1983). "Farewell to paleodemography?" Rumors of
its death have been greatly exaggerated. Journal of Human Evolution 12: 353-360.
Walker, P. L. (1986). Porotic hyperostosis in a marine-dependent California Indian population.
American Journal of Physical Anthropology 69: 345-354.
V~alsh, J. A. (1990). Estimating the burden of illness in the tropics. In Warren, K. S., and
Mahmoud, A. A. E (eds.), Tropicaland Geographical Medicine, McGraw-Hill Information
Services, New York, pp. 185-196.
WeatheraU, D. J., and Wasi, P. (1990). Anemia. In Warren, IC S., and Mahmoud, A. A. E
(eds`), Tropicaland GeographicalMedicine, McGraw-Hill Information Services, New York,
pp. 55-65.
Webster, D., Sanders, W. Z, and van Rossum, R (1992), A simulation of Copan population
history and its implications. Ancient Mesoamerica 3: 185-197.
White, C. D. (1986). Paleodiet and Nutrition of the Ancient Maya at Lamanai, Belize: A Study
of Trace Elements, Stable Isotopes, Nutritional and Dental Pathologies, Unpublished M.A.
thesis, ~ e n t University, Peterborough, ON Canada.
White, C. D. (1994). Dietary dental pathology and cultural change in the Maya. In Chan, L.
IL W., and Herring, A. (eds.), Strength in Diversity, Canadian Scholar's Press, "lbrunto,
pp. 279-302.
White, C. D. (1997). Ancient diet at Lamanai and Pacbitun: lmplicatiom for the ecological
model of collapse. In Whittington, S., and Reed, D. (eds.), Bones of the Ancestors: Recent
Studies of Ancient Maya Skeletons, Smithsonian Institution Press, Washington, DC (in
press).
White, C. D., and Schwarcz, H. P. (1989). Ancient Maya diet: As inferred from isotopic and
chemical analysi.~of human bone. Journal of Archaeological Science 16: 451--474.
White, C, D., Heal),, P. E, and Schwartz, H. R (1993). Intensive agriculture, social status and
Maya diet at Pacbitun, Belize. Journal of Anthropological Research 49: 347-375.
White, C, D., Wright, L E., and Pendergast, D. M. (1994), Biological disruption in the Early
Colonial Period at Lamanai. In ~ n ,
C. S., and Milnet, G. (e~.), In the Wake of
Contact: Biological Responsa to Conquest, Wiley.Liss, New York, pp. 135-145.
Whittington, S. L. (1989). Characteristics of Demosraphy and Disease in Low Status Maya from
Classic Period Copan, Honduras, Unpublished Ph.D. dissertation, Pennsylvania State
University, University Perk,
Whittington, S. L. (1991). Detection of significant demographic differences between
subpopulations of Prehispanic Maya from Copan, Honduras, by survival analysis.
American Iournal of PhysicalAnthmpoloU 85: 167-184,
198
Wright and White
Whittington, S. L. (1992). Enamel hypoplasia in the low status Maya population of prehispanic
Copan, Honduras. In Goodman, A. L., and Capasso, L. L. (eds.), Recent Contributions
to the Study of Enamel Developmental Defects, Journal of Paleopathology, Monographic
Publications 2, Edigrafital Teramo, Chieti, Italy, pp. 185-205.
Whittington, S. L, and Reed, D. (1994)o Los esqueletos de Iximch6. In Laporte, J. P., and
Escobedo, H. L. (eds.), Iill Simposio de InvestigacionesArqueol6gicas en Guatemala, 1993,
Ministerio de Cuttura y Deportes, Instituto de Antropologfa e Historia, Asociaci6n Tikal,
Guatemala, pp~ 23-28.
Whittington, S. L., and Reed, D. M. (1996)~ Evidence of diet and health in the skeletons of
Iximch6. In Robinson, Eugenia (ed.), Estudios Kaqchiqueles: In Memory of William R.
Swezey~ CIRMA, Antigua, Guatemala (in press).
Willey, G. R. (1973). The Altar de Sacrificios Excavations: General Summary and Conclusions,
Peabody Museum of Archaeology and Ethnology, Papers, Vol. 64, No. 3, Harvard
University, Cambridge, MA.
Willey, G. R., and Shimkin, D. B. (1973). The Maya Collapse: A summary view. In Culbert,
T. E (ed.), The Classic Maya Collapse, University of New Mexico Press, Albuquerque, pp.
457-502.
Willey, G. R., Bullard, W R., Glass, J. B., and Gifford, J. C. (1965). Prehistoric Maya
Settlements in the Belize Valley, Peabody Museum of Archaeology and Ethnology, Papers,
VoL 54, Harvard University, Cambridge, MA.
Williams, G. D. (1931). Maya-Spanish Crosses in Yucatan, Peabody Museum of Archaeology
and Ethnology, Papers, Vol. 13, No. 1. Harvard University, Cambridge, MA.
Wiseman, E (1985). Agriculture and vegetation dynamics of the Maya collapse in central
PetEn, Guatemala. In Pohl, M. D. (ed.), Prehistoric Lowland Maya Environment and
Subsistence Economy, Peabody Museum of Archaeology and Ethnology, Papers, Vol. 77,
Harvard University Press, Cambridge, MA, pp. 63-71.
Wood, J. W, Milner, G. R., Harpending, H. C., and Weiss, K. M. (1992). The osteological
paradox: Problems of inferring prehistoric health from skeletal samples. Current
Anthropology 33: 343-370.
Wright, L E. (1990). Stresses of conquest: A study of Wilson bands and enamel hypoplasias
in the Maya of Lamanai, Belize. American Journal of Human Biology 2: 25-35.
Wright, L. E. (1994). The Sacrifice of the Earth.? Diet, Health, and Inequality in the Pasi6n
Maya Lowlands, Unpublished Ph.D. dissertation, University of Chicago, Chicago.
Wright, L. E. (1995). The elements of Maya diets: Alkaline earth baseline,s and paleodietary
reconstruction in the Pasi6n Zone. In White, C. D. (ed.), Reconstructing Ancient Maya
Diet, Gordon and Breach Science Publications, Newark, NJ (in press).
Wright, L. E, (1997). Ecology or society? Paleodiet and the collapse of the Pasi6n Maya
Lowlands. In Whittington, S,, and Reed, D. (eds.), Bones of the Ancestors: Recent Studies
of Ancient Maya Skeletom, Smithsonian Institution Press, Washington, DC (in press).
Wright, L. E., and Schwarcz, H. E (1996). Infrared and isotopic evidence for diagenesis of
bone apatite at Dos Pilas, Guatemala: Paleodietary imptications. Journal of Archaeological
Science 23 (in press).