Mammals & Climate
Russell W. Graham
Earth & Mineral Sciences
Museum
Pennsylvania State University
University Park, PA 16802
rgraham@ems.psu.edu
Vertebrate fossil collection
Megafauna collection
Microfossil collection
Excavating & bagging
sediment with bones
Screen washing
Sediment for bones
A volunteer excavates around a mammoth vertebra at the Pratt Mammoth site, KS
boneblogger.com/mapping-the-pratt-mammoth-excavation-using-gps-and-basic-surveying-technology
Picking screenwash
Concentrate for bones
Why Mammals
Abundant sites and specimens with electronic databases
Excellent Geographic Coverage
Can directly date individual specimens
Small mammals can not migrate (local environment)
Can be identified to generic and frequently species level
Ecology of modern forms well studied so good proxies
http://www.mnh.si.edu/mna/about.cfm
Many taxa are limited to specific habitats
Databases
http://www.neotomadb.org/
http://www.ucmp.berkeley.edu/miomap/
Accuracy and Precision of
AMS Radiocarbon Dating Bone
From T. S. Stafford, Jr.
Individual specimens as small as rodent
and insectivore skulls & jaws can be dated
And in some cases even isolated teeth and
Fragmentary bones can be dated accurately
and precisely
From T. S. Stafford, Jr.
Identification of Shrews
Sorex palustris
(water shrew)
Blarina brevicauda
(short tailed shrew)
Cryptotis parva
(least shrew)
Barren ground musk oxen (Ovibos moschatus)
have specific physiological and anatomical adaptations for cold climates
Modern (shaded in inset) & Late Pleistocene (dots) distribution of the collared
lemming (Dicrostonyx sp.) in North America
Morphological and physiological
Adaptations for cold climates
Winter pelage
Summer pelage
Data from Neotoma Database
Modern environment
Brown lemmings (Lemmus trimucronatus) have
behavioral adaptations for cold climate
Subnivian environment protects
the brown lemming from the cold.
Squirrels – Habitats – Climate
Grassland
“Dry”
Glaucomys
-------------------------------------------------------- Forest
“Moist”
Prairie dog –-shortgrass
Cynomys
Marmot – grassy area in coniferous forest
or alpine tundra – Marmota flaviventris
Tamiasciurus
Sciurus niger
Chipmunk –woodland –
Tamias
Thirteen line ground squirrel – short to tall grass
Spermophilus tridecemlineatus
Sciurus
carolinensis
Woodchuck – grassy areas in forestMarmota monax
Franklin’s ground squirrel – tall grass
Spermophilus franklinii
Tree
Squirrels
Closed
Forest
Squirrels & Vegetation
No-analog Vegetation:
Several Thousand Year
Intervals
&
Extends into Holocene
Non-analog Mammals: 500 year intervals, extend
From Overpeck et al. 1992
throughout late Pleistocene & beyond, absent in Holocene
Was there a continental-wide Clovis Drought?
NO
Taxa
Sites
WEST
------------------------------------------------------------ EAST
LR-AZ
AU-TX
X
X
X
X
X
LF-SD
KW-MO
Grassland/Dry/Warm
Bison sp.
Camelops hesternus
Mammuthus columbi
Perognathus sp.
Onychomys leucopus
Spermophilus sp.
Geomys sp.
Spermophilus franklini
Spermophilus tridecemlineatus
X
X
X
X
X
X
X
X
X
Woodland/Forest/ Cool/Moist
Tapirus merriami
Ursus americanus
Synaptomys cooperi
Scalopus aquaticus
Blarina sp.
Sorex palustris
Sorex hoyi
Clethrionomys gapperi
Zapus princeps
Mylohyus sp.
Mammut americanum
Marmota monax
Sciurus sp.
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Permanent Water
Ondatra zibethica
Osteichthyes
Mustela vison
X
X
X
X
X
X
X
LR- Lehner Ranch, AZ; AU- Aubrey, TX; LF- Lange Ferguson, SD; KW-Kimmswick, MO
•
Selected Environmentally Sensitive Taxa from Clovis Sites
(Data derived from Neotoma Database)
Selected Environmentally Sensitive Taxa from Clovis Sites (Data derived from Neotoma Database)