n, G

The d13C values discriminate between different types ofBones

Bones and teeth are composed of both organic and mineral

fractions which are synthesized during the lifetime of a verte-

brate (Figure 1). The organic fraction of bone and dentine is

Broadmeadow et al., 1992; Gebauer and Schultze, 1991; van

der Merwe and Medina, 1991). As herbivore teeth and bones

record the d13C values of their plant food, it is possible to identifywhich kind of plant was consumed by an herbivore, and there-

fore the type of environment in which it lived (Figure 3).Since the 1970s, stable isotopes in terrestrial teeth and bones

have been providing paleoenvironmental and paleobiological

information on the Quaternary period. Indeed, the skeletal

tissues of an animal through its diet and drinking water yield

paleoenvironmental information in the form of isotopic ratios.

This information is preserved in molecules and minerals found

in fossil teeth and bones.

The most commonly used pairs of isotopes are 13C/12C,15N/14N, and 18O/16O. Isotopes correspond to different types

of atoms for a given chemical element, meaning that two iso-

topes of the same element have the same number of protons,

but differ in the number of neutrons. For instance, an atom of12C (carbon-12) has six protons and six neutrons in its core,

while an atom of 13C (carbon-13) has six protons and seven

neutrons. Therefore, 13C exhibits a higher atomic weight than12C and is thus referred to as the heavy isotope (contrary to12C, which is referred to as the light isotope). Nevertheless,

both isotopes enter in the same molecules with the same types

of chemical bonds. The relative proportion of 13C and 12C in a

given molecule is not random but depends on the relative

content of both isotopes in the source of carbon used to

synthesize this molecule and on the differences of behavior

between both isotopes during chemical reactions.

The relative abundances of the different isotopes are much

higher for light isotopes than for heavy isotopes (e.g., Koch,

2007). The variations of isotopic abundances in natural sam-

ples are very small. They are measured using an isotopic ratio

mass spectrometer, which separates and quantifies the number

of heavy and light isotopes of a given element. In order to

ensure accuracy, measurements are performed simultaneously

on the test sample and on a standard, which allows corrections

that make all results comparable to one another. Due to this

measurement strategy, the results are expressed as relative

abundances, known as delta (d) values, which are defined asfollows:

dEX ERsampleERsample

ERsample 1000%

where EX stands for 13C, 15N, or 18O, respectively. International

reference standards have been established for d13C values (ma-rine carbon PeeDee Belemnite (PDB)), for d15N values (atmo-spheric dinitrogen), and for d18O values (an average mixture ofoceanic waters called Standard Mean Ocean Water (SMOW)).

Paleobiological Tracking by Isotopes in Teeth andTerrestrial Teeth and BonesH Bocherens and D G Drucker, Universitat Tubingen, Tubinge

2013 Elsevier B.V. All rights reserved.

Introduction304plants, principally between marine and terrestrial plants.

Among terrestrial plants, the carbon isotope signature varies

between plants using the two main photosynthetic pathways,

calledC3 andC4 (C3 plants and C4 plants). C4 plants are absent

or very limited in environments with a mild or cold growing

season, as in Europe, Northern latitudes, and high altitudes

(Ehleringer et al., 1997). When present, C4 plants are grasses

and forbs. In environments where all plants use the C3 photo-

synthetic pathway, an isotopic distinction can be seen between

plants growing under a closed canopy and those at the top of the

canopy or growing in an open environment. The possible causes

of the so-called canopy effect are the concentration of recycled

CO2 due to poor ventilation, the light attenuation, and the

relative high water availability in closed canopy forest (e.g.,ermany

mainly formed of a protein, collagen, which contains carbon

(around 40%) and nitrogen (around 15%), while the mineral

fraction contains carbon and oxygen. Enamel is formed of a

very small organic fraction devoid of collagen. In bone, den-

tine, and enamel, the mineral fraction is composed of a cal-

cium phosphate (apatite) with many impurities, including

35% carbonate. The crystal size of apatite is much larger in

enamel than in bone and dentine. The isotopic signatures of

nitrogen are measured in the organic fraction, while oxygen

isotopic signatures are measured in the mineral fraction, both

in phosphate and carbonate. The isotopic signatures of carbon

can be measured in the organic and the mineral phases of bone

and dentine, and in the mineral fraction of enamel.

Carbon

All the carbon of an organism comes from its dietary intake, in

the form of proteins, carbohydrates, and lipids. Some of these

nutrients are incorporated directly by the organism and seques-

tered in different tissues, while other molecules are synthesized

by the organism from dietary nutrients. Due to these different

biochemical characteristics and isotopic fractionations, the av-

erage carbon isotopic abundance of a vertebrate is close to that

of its average diet, but those recorded in a given tissue or

molecule exhibit specific differences (Figure 2). The d13Cvalues of collagen are typically 5% more positive than thoseof the average diet, while the d13C values of the carbonatefraction of bone and tooth mineral fraction is 914% morepositive than that of the average diet (Cerling and Harris, 1999;

Passey et al., 2005). Therefore, the d13C values of collagen andcarbonate apatite are typically used to track the type of plant

food consumed by herbivores and the type of plants at the base

of the food web to which predators belong.

n: ~

ge-co

: ~

ho ~5%

car

CARBONATE STABLE ISOTOPES | Terrestrial Teeth and Bones 305Bone

Organic fractio

Organic fraction: ~30%90% colla10% non

Mineral fraction

Calcium p(includes

Mineral fraction: ~70%

(includes ~3% Nitrogen

Nitrogen is incorporated through dietary intake in the organic

molecules of an organisms tissues. It is usually measured in

the collagen preserved in fossil bones. Contrarily to carbon, the

isotopic signature of nitrogen is significantly enriched in verte-

brate tissues relative to its average diet, typically by 35%(Figure 2; review in Robbins et al., 2005). Therefore, the nitro-

gen isotopic signature of a given individual depends on the

isotopic signature at the base of the food web to which it

belongs (in the plants), and on the position of the specimen

within the food web (herbivore or predator). Not all herbi-

vores present the same d15N values in a given ecosystem be-cause different plants may use nitrogen under different forms,

leading to varying isotopic fractionation and d15N values. For

Figure 1 Summary of the composition of bones and teeth, with emphasis oenamel.

Carbon(d13C)

Inorganicprecursors

Producer(Plants)

C3 Plants(~ 28C4 Plants(~ 13

Marine Pla(~ 20

Non N2 fixing P(~ -5 to +5

H2O in leaO in nutrie

N2 fixing Pla(~ 0)

(variable accoto taxon)

O2

CO2(~ 8)

HCO3-

(~ 0)

(variable)N2 (~0)

H2O(variable

according toenvironment)

NO2NO3NH4

O2

Nitrogen(d15N)

Oxygen(d18O)

Figure 2 Summary of the isotopic fractionation factors associated with thehydrological cycle, with emphasis on bone and tooth tissues. Bold arrows indTooth

Dentine

nllagenous proteins and lipids

~22%

sphate d18Od13C, d18O carbonate)

~78%

d13C, d15NEnamel1%99% calcium phosphate d18O

d13C, d18Obonate)instance, grass and graminoids typically exhibit more positive

d15N values than shrubs and trees, as the latter obtain theirnitrogen through symbiotic fungal mycorrhizae (e.g., Michel-

sen et al., 1998; Schulze et al., 1994). Global climatic factors

such as aridity and temperature lead to increased d15N valuesof plants (Amundson et al., 2003), while d15N of plants tendsto decrease with increasing altitude (e.g., Mannel et al., 2007).

Fire also tends to increase d15N values of plants growing aftersuch an event (Hogberg, 1997).

Oxygen

Oxygen isotopic signatures are measured in the mineral phase

of enamel, dentine, or bone, in the phosphate or the carbonate

n the isotopic signatures that can be retrieved from bone, dentine, and

s Consumers(body average)

Consumers(bone/tooth)

)

)nts)

lants)

vesnts

nts

rding

CO2

H2O

+3 to +5

+ 01+5 in collagen

+18 in PO4

+26 in CO3

Collagen

+9 to +14 incarbonate apatite

transfer of carbon, nitrogen, and oxygen within food webs and theicate steps where significant isotopic fractionation occurs.

--

-

-

d1

d1

d1

Sa

osite d

306 CARBONATE STABLE ISOTOPES | Terrestrial Teeth and Bones-40 -35

-35

-30

-30 -25

-25

-30 -25

-30 -25d13C

Browsers (C3)

Zoo (C3)

Mongolia (C3)

Figure 3 An example of the reconstruction of the carbon isotopic compon their habitat. The d13C of diet has been calculated by adding 14% to thC3 - Grass13C = -26.7 2.3fractions (Kohn and Cerling, 2002). For both fractions, the

d18O values are related to those of environmental water,through drinking water. However, there are complications

due to the incorporation of water from food, and mixture

with oxygen from respiration (Figure 2). This leads to varying

species-dependent relationships between d18O values in car-bonate or phosphate and d18O values in environmental watertaken by the organisms. However, both d18O values are linkedby a clear relationship, independent of the organism.

Variation in oxygen isotope ratios studied from terrestrial

environments is ascribed to environmental temperature changes,

with warmer weather resulting in more positive d18O values andcoolerweather resulting inmorenegative d18O values inmeteoricwaters. However, the pattern is different in warm environments,

where the temperature is higher than 20 C. In such contexts, thed18O values decrease when the amount of precipitation increases.Local parameters, such as evaporation in ponds or streams orig-

inating at high altitudes, may provide drinking water to terrestrial

vertebrates with d18O values different from those of local precip-itation, and thus complicate the interpretation of the oxygen

isotopic composition of fossil teeth and bones.

Chronological Resolution of Skeletal Tissues

Different tissues record the isotopic signature of food or drinking

water during the period of their synthesis. Typically, bone grows

during the first stages of ontogeny, but in higher vertebrates such

Cerling and Harris, 1999). The reconstructed diet of zebras (Equus burchelli)grasses, while those living in a zoo and fed with C3 plants track this differenteating C3 plants in a Mongolian grassland.20 -15 -10

20 -15 -10

20 -15 -10 -53C

3C

3C

vannah

Kenya (C4)

Zebra(Equus burchelli)

Horse(Equus caballus)

Grazers (C4)

ion of the diet consumed by modern equids (horses and allies) based13C values measured in carbonate hydroxylapatite (data from20 -15 -10 -5

C4 - Grass13C = 12.5 1.1as mammals and birds, it continues to remodel and therefore

incorporates newer carbon, nitrogen, and oxygen atoms. An

adult mammal thus dies with its bone isotopic signature reflect-

ing the last years of its lifetime. In contrast to this, mammalian

dental tissues such as dentine and enamel form during a limited

period of an individuals lifetime, and once formed, do not

remodel. In an adult mammal, teeth exhibit isotopic signatures

corresponding to the early years of the individual, depending on

the chronology of tooth development for a given species. Cross

sectionsof dentine and enamel retain their isotopic signature in a

chronological order reflecting time of assimilation (e.g., Drucker

et al., 2010; Fraser et al., 2008). Tooth enamel may thus record

seasonal variations of d18O values (Figure 4). The level of reso-lution in such tissues, especially tooth enamel, is still under

debate as each volume of tissue forms over a significant amount

of time (e.g., Kohn and Cerling, 2002).

Physiological Effects (Suckling, Hibernation, Starvation,and Water Stress)

Some events in the life of a vertebrate can complicate the

record of dietary isotopic signatures. In mammals, diet changes

dramatically between the nursing and adult stages, following

weaning. Maternal milk exhibits isotopic signatures different

from those of the average adult diet, especially with more

positive d15N values and more positive d18O values (Wrightand Schwarcz, 1998). Therefore, suckling mammals exhibit

living in a Kenyan savanna exhibit d13C values similar to those of C4diet, and exhibit d13C values similar to those of horse (Equus caballus)

assessed by the nitrogen content of bulk sample as a proxy

10

09 10 11 12 1

40

n spto

CARBONATE STABLE ISOTOPES | Terrestrial Teeth and Bones 307isotopic differences relative to their adult counterparts, and

tissues formed during this formative period of life, such as

deciduous teeth and first molars, usually exhibit isotopic shifts

relative to other teeth and bone tissues formed after weaning.

In hibernating mammals, such as bears, carbon and nitrogen

isotopic signatures shift in bloodduring thewinter sleep and these

shifts are recorded in tooth dentine (Bocherens, 2004). Starvation

and water stress is also a phenomenon that has been suggested

to induce 15N shifts in vertebrate tissue (Ambrose, 1991), but

recent research on captive and wild mammals suggests that the

18OPO4

Figure 4 Variations of d18O in deer enamel reflect seasonal variations, iThe differences in amplitudes and absolute values of d18O values are dueWINTER

10

20

30

Hei

ght

(mm

)Wyoming

50

60changes in 15N abundances coincident with harsh environments

are most likely due to isotopic changes in the plants, while the

fractionation between diet and animals remains relatively con-

stant (e.g., Hartman, 2010; Murphy and Bowman, 2006).

Diagenetic Alteration

The chemical composition of bone and tooth is modified after

an individuals death, through physical, chemical, and bio-

chemical mechanisms called diagenesis. The intensity of dia-

genetic alteration depends on the time elapsed since death, but

also on sedimentary conditions. High temperatures and hu-

midity as well as high levels of microbial activity will increase

the intensity of diagenetic transformation, increasing the

chances of alteration of the biogenic isotopic signatures.

Organic Fraction

Collagen in fossil bones and dentine can survive for tens of

thousands of years under favorable conditions. Cold and dry

climatic conditions are more favorable than warm and humid

ones, while cave deposits are more favorable than open-air

sites. Collagen preservation in fossil skeletal remains can be(e.g., Bocherens et al., 2005a).

Fossil collagen can be purified through several methods.

The reliability of the isotopic signatures of ancient collagen is

assessed through its chemical similarity to collagen from fresh

bone. Fossil organic extracts with atomic C/N ratios lower than

2.9 or higher than 3.6 are considered unreliable, as well as

those containing less than 5% nitrogen (e.g., Ambrose, 1990).0

3 14 15

14 15 16 17

SUMMER

ecimens from Wyoming and Croatia (based on Fricke et al., 1998).different climatic regimen in both areas.20

Croatia

SUMMERMineral Fraction

While it is almost always possible tomeasure carbon and oxygen

signatures from fossil bones and teeth, the key question is to

determine whether the measured values correspond to those

recorded in the organisms tissues when it was alive. Evaluating

the extent of diagenetic alteration can be done either using the

pattern of isotopic variations observed in the fossil samples as

compared to equivalent modern ones, or using indirect tracers

of modifications, such as crystallinity indexes and uptake of

trace elements (e.g., Kohn and Cerling, 2002). It is commonly

assumed that the isotopic signatures of enamel are much more

stable through time than those of dentine and bone, while the

phosphate fraction is more stable than the carbonate fraction.

However, the phosphate fraction can be also affected under

special circumstances. The best approach is to assess the extent

of diagenetic alteration in each studied site using as many dif-

ferent proxies as possible (e.g., Kohn et al., 1999).

Reconstruction of Terrestrial Paleoenvironments

Tropical Environments

Paleoenvironments where C3 and C4 plants coexist are partic-

ularly favorable for isotopic tracking with carbon in teeth and

brates document these changes in the proportions of con-

Studies based on late Quaternary herbivore tooth enamel

isotopic fractionation is transferred to herbivores consuming

such plants in dense canopy forests. It is thus possible to track

308 CARBONATE STABLE ISOTOPES | Terrestrial Teeth and Bonesshowed that the proportions of C3 and C4 plants in the North-

ern Cape Province, South Africa, did not reflect the predictions

of climatic models about winter and summer rainfall regimes

(Lee-Thorp and Beaumont, 1995) and documented episodes

of wetter and drier conditions from 16000 years ago (Smith

et al., 2002).

AridityIn tropical environments, aridity has been recognized as

a factor influencing the d15N of herbivore collagen, withmore positive d15N values under more arid conditions (e.g.,Ambrose, 1991; Hartman, 2010; Murphy and Bowman, 2006;

Schwarcz et al., 1999). This led to the possibility of quantifying

past annual rainfall based on the d15N of herbivorous taxa, forinstance, macropods (kangaroos) in Australia (Grocke et al.,

1997).

Decreasing humidity has an effect on bone because of

increasing evapotranspiration in leaves, leading to d18O in-crease in leaf water, which is recorded in bone phosphate

(e.g., Ayliffe and Chivas, 1990; Luz et al., 1990). In combina-

tion with high d13C values, the high d18O values exhibitedby middle Pleistocene representatives of marsupial species

that became extinct in the late Pleistocene demonstrate that

these fauna could survive arid episodes, which weakens the

hypothesis that increasing aridity may have led to their final

extinction around 50000 years ago (Prideaux et al., 2007).

Ecological Flexibility of Large MammalsIsotopic tracking of habitat through the plants consumed by

ancient herbivores is a taxon-free approach, and therefore can

be used to document possible diet and habitat change ofsumed plants. However, other factors such as the atmospheric

pressure of CO2 also play a role in this equation (Ehleringer

et al., 1997; Koch et al., 2004). The main climatic parameter in

these environments is the amount of annual rainfall, and

nitrogen isotopic signatures of herbivores can be used to

track past variations in aridity. Some examples are given in

the following section.

Development of C4 biomes during the late QuaternaryThe open environments of the southern half of the North

American continent are a place of competition between C3and C4 herbaceous plants. Today, there is a clear gradient of

decreasing proportions of C4 plants toward the north, with

about 10% of C4 plants at 48N. Carbon and oxygen isotopic

studies of late Pleistocene herbivore tooth enamel from south-

western United States demonstrated the role of low atmo-

spheric CO2 in the expansion of C4 plants during the Last

Glacial Maximum, an expansion that could not be predicted

based on temperature and precipitation changes alone (e.g.,

Koch et al., 2004).bones. Indeed, C4 plants increase in proportion as climatic

conditions become drier and warmer, and C3 plants increase

in proportion as moisture increases. As the difference between

d13C values of these plants relative to C3 plants is around 12%,the d13C value recorded in the skeletal tissues of fossil verte-the changes of habitat for large herbivores at the beginning

of the Holocene in Europe (Figure 6; e.g., Drucker et al.,

2003a, 2008).

Variations in d15N values in ungulate bone collagen seem torelate to changes in soil microbial activity during the climatic

oscillations that occurred in Europe since 30000 years ago

(Drucker et al., 2003a,b; Hedges et al., 2004; Richards and

Hedges, 2003): low temperatures led to decreased microbial

activity and thus reduced nitrogen isotopic fractionation that is

transferred in plants consumed by herbivores. Indeed, a de-

crease in d15N values is recorded during the cold peaks of theLast Glacial Maximum and of the Younger Dryas, while an

increase in d15N values is documented during the warming ofthe BollingAllerod Interstadial and that of the early Holocene

(Preboreal and Boreal). The role of climate fluctuations to

explain these trends in d15N values was confirmed by thed18O values of the phosphate of the same bones that trackstemperature changes, and the observed correlation between

increasing d15N and d18O values, and hence temperature, dem-onstrates the relationship between increasing d15N values inred deer bone collagen and warming in this context (Drucker

et al., 2009). These nitrogen isotopic excursions present geo-

graphic variations according to the intensity of the temperature

changes.some species in relationship with climate change or anthro-

pogenic pressure. For instance, some large herbivores from

the Pleistocene in Florida exhibit diet and presumably habitat

stability between glacial and interglacial periods, such as tapir

and mastodon that remain browsers (C3 diet), while horses

remain grazers (C4 diet). In contrast, other species such as

white-tailed deer exhibit less negative d13C values during theinterglacial period, but still within the C3 diet values, while

extinct camel Hemiauchenia and extinct peccary Platygonus

exhibit a clear shift from C3 to C4 diet between glacial and

interglacial periods (DeSantis et al., 2009; Figure 5). By com-

paring the d13C values of modern mammals in southeasternAsia with those of the same species or related taxa in a

middle Pleistocene glacial site in Thailand, it was possible

to establish that some species were real forest dwellers, such

as Java rhinoceros and orangutan, while others that are now-

adays restricted to forest environments were dwelling in C4savanna, such as the small bovid Capricornis, a likely conse-

quence of increasing anthropogenic pressure (Pushkina et al.,

2010; Figure 5). These examples illustrate how isotopic

tracking can be used to document possible habitat changes,

even for species with modern relatives living in a restricted

environment or with a morphology seemingly adapted to a

given diet and habitat.

Temperate and Boreal Environments

In terrestrial environments, where all plants use the C3 photo-

synthetic pathway, plant d13C values exhibit some differencesrelated to environmental parameters (e.g., Heaton, 1999). In

particular, plants growing under a closed canopy exhibit sig-

nificantly more negative d13C values relative to those growingat the top of the canopy or in open environments. This carbon

Atlantic

-19

-20

-21

-22

d13 C

coll

()

-23

-24

-25

-266000 7000 8000 9000 10000 11000

Age cal BP (years)

12000 13000

French Jura

French Alps

14000 15000 16000

+

Pollen record in French Jura

-

CA

NO

PY

EFF

EC

T

Boreal PreborealYoungerDryas

OldestDryas

Allerd Blling

Figure 6 Evolution of collagen d13C values in red deer (Cervus elaphus) bones from French Jura and French Alps (data from Drucker et al., 2003a,2008). The late Pleistocene samples exhibit d13C values indicative of open environments, while Holocene specimens present more negative d13C valuesin Jura, similar to those exhibited by modern large herbivores dwelling in a closed canopy forest. In the Alps, red deer remain in open environments,probably at higher altitudes.

Denser forest

Florida

SE Asia

C3

-20 -15 -10 -5 0 5

Inglis 1A (Glacial)

Leysey 1A (interglacial)

Thum Wiman Nakin (Saalian)

Modern

-20 -15 -10

d13C-5 0 5

C4C3+C4

Figure 5 d13C values of tooth enamel illustrate stability or changes in diet between glacial and interglacial periods in Florida (top, data from DeSantiset al., 2009) and between Saalian (glacial) and modern (interglacial) periods in southeastern Asia (bottom, data from Pushkina et al., 2010).

CARBONATE STABLE ISOTOPES | Terrestrial Teeth and Bones 309

hominids in Africa. Indeed, modern African apes are restricted

rounding environment, it seems that the most likely explana-

tion for this C4 diet should include a mixture of underground

thals had diets that did not differ significantly from those of

from North America were vegetarian when they coexisted with

310 CARBONATE STABLE ISOTOPES | Terrestrial Teeth and Bonesplant storage organs and animals resources (Lee-Thorp et al.,

2010). In East Africa, high d13Cmeasured in some Paranthropusboisei seems to reflect the consumption of abundant C4 sedges

(Figure 7; Lee-Thorp et al., 2010). In contrast, an older hom-

inid from the Pliocene, Ardipithecus ramidus, did not incorpo-

rate C4 resources in its diet although these resources were

present in the environment (Lee-Thorp et al., 2010). This

supports the view that hominid evolution is linked to savanna,to forested environments, and savanna environments require

special skills for exploitation by primates, such as a bipedal gait

and strong social bonds. The d13C values of tooth enamelof fossil mammals, including hominids, from South Africa,

ranging in age from 1.8 to 1.5 million years old, indicate a

significant C4 component in the environment, as well as sig-

nificant C4 dietary inputs for hominids of the species Para-

nthropus robustus, and Homo ergaster (Figure 7; Lee-Thorp

et al., 2000, 2003, 2010). This C4 dietary input could be linked

to the consumption of C4 plant parts, but also to the consump-

tion of animals feeding on C4 plants, such as invertebrates,

small vertebrates, or grazer meat. Based on other evidence such

as tooth microwear and abundance of C4 plants in the sur-Seasonality

Using carbon and oxygen isotopic variations in hypsodont tooth

enamel, as in horse and bison, allowed the reconstruction of

seasonal changes in consumed plant food and precipitation

isotopic signatures, thus leading to a better understanding of

past climatic regimen and events preceding the death of ancient

animals (e.g., Gadbury et al., 2000; Higgins and MacFadden,

2004, 2009; Kohn andCerling, 2002; Passey and Cerling, 2002).

Reconstruction of the Paleobiology of Extinct Species

Using skeletal material from which collagen can be extracted,

it is possible to reconstruct some aspects of animal diet using

carbon and nitrogen isotopic signatures, because different

dietary items exhibit different isotopic signatures, such as

C3 or C4 plants, animal flesh, or food resources of marine

origin. With material too old or too altered to yield collagen,

the carbon isotopic signatures of tooth enamel can be used

to test dietary hypotheses in contexts where different food

webs start with plants exhibiting different d13C values, suchas tropical environments where C4 grasses coexist with C3tree leaves.

Subsistence Patterns of Ancient Hominids

Environmental and dietary changes are often linked to key

stages of the evolution of hominids. In some cases, the possible

impact of such changes can be tested using the isotopic signa-

ture of fossil bones and teeth.

The importance of savanna for African PliocenePleistocenehominidsA hotly debated issue in the study of Quaternary terrestrial

paleoenvironments is the role of savanna in the evolution ofthe carnivorous short-faced bears, but they became much more

carnivorous after the extinction of these meat-eating bears

(Barnes et al., 2002).early anatomically modern humans (Drucker and Bocherens,

2004). This supports the hypothesis of dietary competition

between Neanderthals and anatomically modern humans

(Bocherens and Drucker, 2006).

Paleodiet of Ancient Bears

Bears, as omnivorous carnivores, form an interesting group to

study using the isotopic approach as their diet can be quite

variable, and sometimes difficult to determine based on their

morphological features. They are all themore interesting because

they have an abundant fossil record, for instance, for cave

bears, and cover a dietary spectrum similar to that of humans.

Detecting changes in bear diet may yield direct information on

the availability of food resources relevant for human diet.

Moreover, the paleogenetics of ancient bears is intensively stud-

ied and combining genetic and paleodietary data through the

evolution of bear lineages provides direct evidence about their

evolutionarybiology.Using carbon- andnitrogen-stable isotopic

signatures, cave bears (Ursus spelaeus) were shown to be essen-

tially vegetarian animals (Bocherens et al., 1994, 2006, 2011a,b),

while the extinct giant short-faced bear (Artodus simus) from

North America has been demonstrated to be a meat eater

(Figure 8; Barnes et al., 2002). Interestingly, the diet of ancient

brown bears living at the same time as extinct bears from spe-

cialized species shifts when the dietary competition stops with

the extinction of their competitor. For instance, brown bearsat least since about 3 Ma, but also contradicts the hypothesis

that different hominids used savanna resources in differing

amounts.

The Diet of Neanderthals and Early Anatomically ModernHumansDuring the Upper Pleistocene, Europe was populated by a

distinctive hominid form, the Neanderthals. The demise of

this hominid around 30000 years ago coincides with the ap-

pearance in Europe of anatomically modern humans, seem-

ingly using a more sophisticated culture. Several Neanderthal

fossils have yielded preserved collagen that could be analyzed

for carbon- and nitrogen-stable isotopic compositions, and

compared to those of Upper Paleolithic anatomically modern

humans (e.g., Bocherens et al., 1999, 2005b, in press; Richards

et al., 2000, 2001, 2008). Comparing Neanderthals with pred-

ators such as hyenas suggests that Neanderthals consumed

mainly large herbivore meat, including a large proportion of

megaherbivores such as mammoth and woolly rhinoceros

(Bocherens et al., 2005b). It appears also that Neanderthals

living under different environmental conditions and at differ-

ent periods had similar diets. Although the absolute isotopic

nitrogen values of early modern humans are higher than those

of the last Neanderthals (Richards and Trinkaus, 2009), possi-

ble variations in the d15N values of the whole terrestrial foodwebs at the same time suggest that, finally, the last Neander-

herbivorous and carnivorous species (data from Fox-Dobbs et al., 2008).These isotopic data of short-faced bears plot together with carnivorous

CARBONATE STABLE ISOTOPES | Terrestrial Teeth and Bones 311-12 -10 -8 -6 -4d13C

-2 0 2 4

-12 -10 -8 -6 -4d13C

-2 0 2 4

Paranthropusrobustus

Homo ergaster

South Africa

Figure 7 Reconstruction of the paleoenvironment and paleodiet offossil hominids from South Africa (Swartkrans Members 1 and 2, 1.5to 1.8 Ma) and East Africa (Olduvai East and Pening, 1.5 to 1.8 Ma).The d13C values of Paranthropus robustus, and Homo ergaster in SouthAfrica show that a significant amount of food resources coming from C4environments (most likely savanna) were consumed by these threehominid species (data from Lee-Thorp et al., 2003). In contrast toParanthropus robustus in South Africa, Paranthropus boisei from EastAfrica exhibits a diet almost completely composed of C4 food resources,while Homo habilis had a diet with d13C values similar to Homo ergasterC3 C4

East AfricaParanthropusboisei

Homo habilis

C3 + C4Paleodiet of Ancient Ungulates

Large herbivorous mammals often exhibit specialized diets, in

connection with their tooth morphology and digestive physi-

ology. The occurrence of some herbivorous mammals in Qua-

ternary fossil and archaeological localities can be used to infer

the paleoenvironments around the site. Isotopic analyses of

fossil herbivores have sometimes yielded additional informa-

tion about the ancient environments in which they used to

dwell, and thus allow more precise reconstructions of the

actual diet of extinct species. For instance, isotopic investiga-

tions of tooth enamel have shown that in southern North

America, horses were mixed feeders consuming C4 grasses

and C3 shrubs, while bisons were grazers, eating only C4grasses (Koch et al., 2004). Horses have hypsodont (high-

crowned) teeth and are traditionally thought to be specialized

grazers. Another example of hypsodont ungulates with diverse

diets are extinct camelids from North America (Feranec, 2003).

Therefore, the specialized morphology of some herbivore teeth

is not always indicative of specialized diet, but rather indicates

dietary flexibility.

Implications for Late Pleistocene Extinctions

The possibility to reconstruct dietary and/or habitat changes

through time for a given species opens the possibility to doc-

ument possible ecological disruption linked to extinctions,

in South Africa.10

9

8

7

6

5

4

d15 N

3

2

1

0

-1

-2-22 -21 -20 -19

d13C

-18 -17 -16

MammuthusEquusBisonBosRangiferPanthera leoCanis lupusBootheriumHomotheriumArctodus

Figure 8 d13C and d15N values of short-faced bears (Arctodus simus)collagen from Alaska and Yukon, compared to those of coevalespecially in the case of the late Pleistocene megafaunal extinc-

tions. Two main explanations are usually given for these ex-

tinctions: climate change and human impact (e.g., Koch and

Barnosky, 2006). Using the isotopic signatures of extinct spe-

cies until the moment they become extinct and those of sur-

viving species before, during, and after the extinction event

may provide information about the factors that could have

changed at this time and therefore help to test different hy-

potheses. In the case of Australia, the stable isotopic tracking of

megafauna paleoecology has yielded very interesting results.

For instance, aridity could be ruled out as a significant factor in

the extinction of megafauna as the extinct species exhibited

carbon and oxygen isotopic signatures that demonstrated that

they did live under arid conditions well before the time of their

extinction (Prideaux et al., 2007). If humans were involved in

the megafaunal extinction in Australia, the question remains

whether their action was mostly direct, through overhunting,

or rather indirect, through environmental disruption, in in-

creasing wildfire frequency for instance. Isotopic tracking, to-

gether with tooth microwear analysis, did provide some

answers to this question. In the case of an extinct giant short-

faced kangaroo Procoptodon, these data suggest a diet including

C4 chenopodiaceae from dry areas and obligate drinking

(Prideaux et al., 2009). Aridity would therefore not be a

problem for this species, but having to go to water holes

would make this species vulnerable to human predation, in

contrast with other kangaroos which survived the extinction

species, such as lion, scimitar-toothed cat, and wolf, clearly indicatingthese that short-faced bears were carnivorous.

additional chemical elements. For instance, the amount of

deuterium, the stable heavy isotope of hydrogen, could be

245: 249261.Bocherens H, Fizet M, and Mariotti A (1994) Diet, physiology and ecology of fossil

mammals as inferred by stable carbon and nitrogen isotopes biogeochemistry:

312 CARBONATE STABLE ISOTOPES | Terrestrial Teeth and Bonesused to study paleoclimates and possible migrations, as it

varies in a way similar to oxygen in relationship with temper-

atures (Bowen et al., 2005; Cormie et al., 1994). The isotopic

signatures of sulfur in collagen may be used to improve paleo-

dietary reconstructions and to provide identification of geo-

graphic origin (Richards et al., 2003).

Improving biomolecular technologies will allow the anal-

ysis of isotopic signatures of other organic compounds, such

as osteocalcin, single amino acids, cholesterol, and fatty acids,

in fossil bones and teeth (e.g., Corr et al., 2005; Smith et al.,

2005, 2009). This is expected to lead to breakthroughs in

retrieving paleobiological information at different timescales

within a single individual, and in obtaining isotopic paleobi-

ological signals in fossil material older than around 100000

years.event, and which can sustain themselves with the water con-

tained in their plant food and do not need to drink at water

holes. An additional contribution of stable isotopic tracking in

the debate on megafaunal extinctions in Australia was to dem-

onstrate that species with dietary specialization were much

more affected by a collapse of ecosystem and that a critical

factor for surviving was the possibility to shift diet (Miller et al.,

2005). A more widespread use of this approach to megafaunal

extinction on other continents should also yield valuable in-

formation. For instance, the carbon- and nitrogen-stable iso-

topes of the last cave lions in Western Europe dated to around

12000 years BP suggest that they have relied mainly on rein-

deer as their preferred prey (Bocherens et al., 2011a). The

extirpation of this predatory species in this region could then

correspond to the coeval extirpation of its main prey.

Perspectives

Stable isotopes in terrestrial teeth and bones have already

yielded invaluable information on Quaternary ecosystems,

and this approach is expected to develop further during the

coming years.

A better knowledge of isotopic variations in modern eco-

systems and modern animals will most probably allow more

accurate paleoenvironmental and paleodietary reconstructions

to be performed based on the stable isotopic signatures of teeth

and bones of Quaternary terrestrial vertebrates. Our under-

standing of the fractionation factors in tissues prone to fossil-

ization still needs improvement, based on controlled diet

experiments of species closely related to the fossil taxa under

study, and on investigations of large mammals in monitored

wild contexts. Also the chronology of isotopic records in incre-

mentally grown tissues, such as tooth enamel, needs more

accurate quantification in the species found in Quaternary

fossil assemblages.

The impact of diagenetic alteration on the isotopic signa-

tures of teeth and bones needs to be better understood, espe-

cially when dealing with the mineral fraction of fossil

vertebrates.

Collagen is currently used for its carbon and nitrogen iso-

topic signatures, but it could yield the isotopic signatures ofImplications for Pleistocene bears. Palaeogeography, Palaeoclimatology,Palaeoecology 107: 213225.

Bocherens H, Germonpre M, Toussaint M, and Semal P (in press) Stable isotopes.In: Semal P and Hauzeur A (eds.) Spy Cave: State of 120 years of PluridisciplinaryResearch on the Betche-aux-Rotches from Spy.

Bocherens H, Stiller M, Hobson KA, et al. (2011b) Niche partitioning between twosympatric genetically distinct cave bears (Ursus spelaeus and Ursus ingressus) andbrown bear (Ursus arctos) from Austria: Isotopic evidence from fossil bones.Quaternary International 245: 238248.

Bowen GJ, Wassenaar LI, and Hobson KA (2005) Global application of stable hydrogenand oxygen isotopes to wildlife forensics. Oecologia 143: 337348.See also: Vertebrate Overview. Archaeological Records: HumanEvolution in the Quaternary; Neanderthal Demise. Carbonate StableIsotopes: Lake Sediments; Nonmarine Biogenic Carbonates;Overview; Speleothems; Terrestrial Organic Materials. Ice CoreRecords: Antarctic Stable Isotopes; Greenland Stable Isotopes.Vertebrate Records: Late Pleistocene Megafaunal Extinctions; LatePleistocene of Southeast Asia. Vertebrate Studies: Ancient DNA;Interactions with Hominids; Speciation and Evolutionary Trends inQuaternary Vertebrates.

References

Ambrose SH (1990) Preparation and characterization of bone and tooth collagen forisotopic analysis. Journal of Archaeological Science 17: 431451.

Ambrose SH (1991) Effects of diet, climate and physiology on nitrogen isotopeabundances in terrestrial foodwebs. Journal of Archaeological Science18: 293317.

Amundson R, Austin AT, Scuur EAG, et al. (2003) Global patterns of the isotopiccomposition of soil and plant nitrogen. Global Biogeochemical Cycles 17(1): 1031.http://dx.doi.org/10.1029/2002GB001903.

Ayliffe LK and Chivas AR (1990) Oxygen isotope composition of the bone phosphate ofAustralian kangaroos: Potential as a palaeoenvironmental recorder. Geochimica etCosmochimica Acta 54: 26032609.

Barnes I, Mattheus P, Shapiro B, Jensen D, and Cooper A (2002) Dynamics ofPleistocene population. Extinctions in Beringian brown bears. Science295: 22672270.

Bocherens H (2004) Cave bear palaeoecology and stable isotopes: checking the rules ofthe game. In: Philippe M, Argant A, and Argant J (eds.) Proceedings of the 9thInternational Cave Bear Conference, Cahiers scientifiques du Centre deConservation et dEtude des Collections (Museum dHistoire naturelle de Lyon)Hors Serie No. 2, pp. 183188.

Bocherens H and Drucker DG (2006) Dietary competition between Neanderthals andmodern humans: Insights from stable isotopes. In: Conard N (ed.) WhenNeanderthals and Modern Humans Met, pp. 129143. Tubingen: TubingenPublications in Prehistory, Kerns Verlag.

Bocherens H, Billiou D, Patou-Mathis M, Otte M, Bonjean D, Toussaint M, andMariotti A (1999) Palaeoenvironmental and palaeodietary implications of isotopicbiogeochemistry of late interglacial Neandertal and mammal bones in Scladina Cave(Belgium). Journal of Archaeological Science 26: 599607.

Bocherens H, Drucker DG, Billiou D, Geneste J-M, and van der Plicht J (2006) Bearsand Humans in Chauvet Cave (Vallon-Pont-dArc, Arde`che, France): Insights fromstable isotopes and radiocarbon dating of bone collagen. Journal of HumanEvolution 50: 370376.

Bocherens H, Drucker D, Billiou D, and Moussa I (2005a) Une nouvelle approche pourevaluer letat de conservation de los et du collage`ne pour les mesures isotopiques(datation au radiocarbone, isotopes stables du carbone et de lazote).LAnthropologie 109: 557567.

Bocherens H, Drucker DG, Billiou D, Patou-Mathis M, and Vandermeersch B (2005b)Isotopic evidence for diet and subsistence pattern of the Saint-Cesaire I Neanderthal:Review and use of a multi-source mixing model. Journal of Human Evolution49: 7187.

Bocherens H, Drucker DG, Bonjean D, et al. (2011a) Isotopic evidence for dietaryecology of cave lion (Panthera spelaea) in North-western Europe: Prey choice,competition and implications for extinction. Quaternary International

CARBONATE STABLE ISOTOPES | Terrestrial Teeth and Bones 313Broadmeadow MSJ, Griffiths H, Maxwell C, and Borland AM (1992) The carbon isotoperatio of plant organic material reflects temporal and spatial variations in CO2 withintropical forest formations in Trinidad. Oecologia 89: 435441.

Cerling TE and Harris JM (1999) Carbon isotope fractionation between diet andbioapatite in ungulate mammals and implications for ecological and paleoecologicalstudies. Oecologia 120: 347363.

Cormie AB, Schwarcz HP, and Gray J (1994) Relation between hydrogen isotopic ratiosof bone collagen and rain. Geochimica et Cosmochimica Acta 58: 377391.

Corr LT, Sealy JC, Horton MC, and Evershed RP (2005) A novel marine dietary indicatorutilising compound-specific bone collagen amino acid d13C values of ancienthumans. Journal of Archaeological Science 32: 321330.

DeSantis LRG, Feranec RS, and MacFadden BJ (2009) Effects of globalwarming on ancient mammalian communities and their environments. PloS One4(6): e5750.

Drucker DG and Bocherens H (2004) Carbon and nitrogen stable isotopes as tracersof diet breadth evolution during Middle and Upper Palaeolithic in Europe.International Journal of Osteoarchaeology 14: 162177.

Drucker DG, Bocherens H, and Billiou D (2003) Evidence for shifting environmentalconditions in Southwestern France from 33000 to 15000 years ago derived fromcarbon-13 and nitrogen-15 natural abundances in collagen of large herbivores.Earth and Planetary Science Letters 216: 163173.

Drucker D, Bocherens H, Bridault A, and Billiou D (2003) Carbon and nitrogen isotopiccomposition of Red Deer (Cervus elaphus) collagen as a tool for trackingpalaeoenvironmental change during Lateglacial and Early Holocene inNorthern Jura (France). Palaeogeography, Palaeoclimatology, Palaeoecology195: 375388.

Drucker DG, Bridault A, Hobson KA, Szuma E, and Bocherens H (2008) Can carbon-13abundances in large herbivores track canopy effect in temperate and borealecosystems? Evidence from modern and ancient ungulates. Palaeogeography,Palaeoclimatology, Palaeoecology 266: 6982.

Drucker DG, Bridault A, Iacumin P, and Bocherens H (2009) Bone stable isotopicsignatures (15N, 18O) as tracer of temperature variation in Lateglacial and earlyHolocene: Case study of red deer from Rochedane site in French Jura. GeologicalJournal 44: 593604.

Drucker DG, Hobson KA, Munzel SC, and Pike-Tay A (2010) Intra-individual variationin stable carbon (d13C) and nitrogen (d15N) isotopes in mandibles of moderncaribou of Qamanirjuaq (Rangifer tarandus groenlandicus) and Banks Island(Rangifer tarandus pearyi): Implications for tracing seasonal and temporal changesin diet. International Journal of Osteoarchaeology 22: 494504. http://dx.doi.org/10.1002/oa.1220.

Ehleringer JR, Cerling TE, and Helliker BR (1997) C4 photosynthsis, atmospheric CO2,and climate. Oecologia 112: 285299.

Feranec RS (2003) Stable isotopes, hypsodonty, and the paleodiet of Hemiauchenia(Mammalia, Camelidae): A morphological specialization creating ecologicalgeneralization. Paleobiology 29: 230242.

Fox-Dobbs K, Leonard JA, and Koch PL (2008) Pleistocene megafauna from easternBeringia: Paleoecological and paleoenvironmental interpretations of stable carbonand nitrogen isotope and radiocarbon records. Palaeogeography,Palaeoclimatology, Palaeoecology 261: 3046.

Fraser RA, Grun R, Privat K, and Gagan MK (2008) Stable-isotope microprofiling ofwombat tooth enamel records seasonal changes in vegetation and environmentalconditions in Eastern Australia. Palaeogeography, Palaeoclimatology,Palaeoecology 269: 6677.

Fricke HC, Clyde WC, and ONeil JR (1998) Intra-tooth variations in d18O (PO4) ofmammalian tooth enamel as a record of seasonal variations in continental climatevariables. Geochimica et Cosmochimica Acta 62: 18391950.

Gadbury C, Todd L, Jahren AH, and Amundson R (2000) Spatial and temporalvariations in the isotopic composition of bison tooth enamel from the EarlyHolocene Hudson-Meng Bone Bed, Nebraska. Palaeogeography,Palaeoclimatology, Palaeoecology 157: 7993.

Gebauer G and Schultze E-D (1991) Carbon and nitrogen isotope ratios in differentcompartments of a healthy and a declining Picea forest in the Fichtelgebirge,NE Bavaria. Oecologia 87: 198207.

Grocke DR, Bocherens H, and Mariotti A (1997) Annual rainfall and nitrogen-isotopecorrelation in Macropod collagen: Application as a paleoprecipitation indicator.Earth and Planetary Science Letters 153: 279285.

Hartman G (2010) Are elevated d15N values in herbivores in hot and arid environmentscaused by diet or animal physiology? Functional Ecology 25: 122131.

Heaton THE (1999) Spatial, species, and temporal variations in the 13C/12C ratios of C3plants: Implications for palaeodiet studies. Journal of Archaeological Science26: 637649.

Hedges REM, Stevens RE, and Richards MP (2004) Bone as a stable isotope archive forlocal climatic information. Quaternary Science Reviews 23: 959965.Higgins P and MacFadden BJ (2004) Amount effect recorded in oxygen isotopes ofLate Glacial horse (Equus) and bison (Bison) teeth from the Sonoran andChihuahuan deserts, Southwestern United States. Palaeogeography,Palaeoclimatology, Palaeoecology 206: 337353.

Higgins P and MacFadden BJ (2009) Seasonal and geographic climate variabilitiesduring the Last Glacial Maximum in North America: Applying isotopic analysis andmacrophysical climate models. Palaeogeography, Palaeoclimatology,Palaeoecology 263: 1527.

Hogberg P (1997) 15N natural abundance in soil-plant systems. New Phytologist137: 179203.

Koch PL (2007) Isotopic study of the biology of modern and fossil vertebrates.In: Michener R and Lajtha K (eds.) Stable Isotopes in Ecology and EnvironmentalScience, 2nd edn., pp. 99154. Boston: Blackwell Publishing.

Koch PL and Barnosky AD (2006) Late Quaternary extinctions: State of the debate.Annual Review of Ecology, Evolution, and Systematics 37: 215250.

Koch PL, Diffenbaugh NS, and Hoppe KA (2004) The effects of late Quaternary climateand pCO2 change on C4 plant abundance in the South-Central United States.Palaeogeography, Palaeoclimatology, Palaeoecology 207: 331357.

Kohn MJ and Cerling TE (2002) Stable isotope compositions of biological apatite.In: Kohn MJ, Rakovan J, and Hughes JM (eds.) Phosphates, Geochemical,Geobiological, and Materials Importance. Reviews in Mineralogy andGeochemistry, vol. 48, pp. 455488. Washington, DC: Mineralogical Society ofAmerica.

Kohn MJ, Schoeninger MJ, and Barker WW (1999) Altered states: Effects ofdiagenesis on fossil tooth chemistry. Geochimica et Cosmochimica Acta63: 27372747.

Lee-Thorp JA and Beaumont PB (1995) Vegetation and seasonality shifts during theLate Quaternary deduced from 13C/12C ratios of grazers at Equus Cave, South Africa.Quaternary Research 43: 426432.

Lee-Thorp JA, Sponheimer M, Passey BH, de Ruiter DJ, and Cerling TE (2010)Stable isotopes in fossil hominin tooth enamel suggest a fundamental dietaryshift in the Pliocene. Philosophical Transactions of the Royal Society B365: 33893396.

Lee-Thorp JA, Sponheimer M, and Van der Merwe NJ (2003) What do stable isotopestell us about Hominid dietary and ecological niches in the Pliocene? InternationalJournal of Osteoarchaeology 13: 104113.

Lee-Thorp JA, Thackeray JF, and van der Merwe NJ (2000) The hunters and the huntedrevisited. Journal of Human Evolution 39: 565576.

Luz B, Cormie A, and Schwarcz HP (1990) Oxygen isotope variations in phosphate ofdeer bones. Geochimica et Cosmochimica Acta 54: 17231728.

Mannel TT, Auerswald K, and Schnyder H (2007) Altitudinal gradients of grasslandcarbon and nitrogen isotope compositions are recorded in the hair of grazers.Global Ecology and Biogeography 16: 583592.

Michelsen A, Quarmby C, Sleep D, and Jonasson S (1998) Vascular plant 15N naturalabundance in heath and forest tundra ecosystems is closely correlated with presenceand type of mycorrhizal fungi in roots. Oecologia 115: 406418.

Miller GH, Fogel ML, Magee JW, Gagan MK, Clarke SJ, and Johnson BJ (2005)Ecosystem collapse in Pleistocene Australia and a human role in megafaunalextinction. Science 309: 287290.

Murphy BP and Bowman DMJS (2006) Kangaroo metabolism does not cause therelationship between bone collagen d15N and water availability. Functional Ecology20: 10621069.

Passey BH and Cerling TE (2002) Tooth enamel mineralization in ungulates:Implications for recovering a primary isotopic time series. Geochimica etCosmochimica Acta 18: 32253234.

Passey BH, Robinson TF, Ayliffe LK, et al. (2005) Carbon isotope fractionation betweendiet, breath CO2, and bioapatite in different mammals. Journal of ArchaeologicalScience 32: 14591470.

Prideaux GJ, Ayliffe LK, DeSantis LR, et al. (2009) Extinction implications of achenopod browse diet for a giant Pleistocene kangaroo. Proceedings of the NationalAcademy of Sciences USA 106(28):1164611650.

Prideaux GV, Long JA, Ayliffe LK, et al. (2007) An arid-adapted middle Pleistocenevertebrate fauna from South-Central Australia. Nature 445: 422425.

Pushkina D, Bocherens H, Chaimanee Y, and Jaeger J-J (2010) First dietary andpaleoenvironmental reconstructions from the late Middle Pleistocene Snake cave inNortheastern Thailand using stable carbon isotopes. Naturwissenschaften97: 299309.

Richards MP, Fuller BT, Sponheimer M, Robinson T, and Ayliffe L (2003) Sulphurisotopes in palaeodietary studies: A review and results from a controlled feedingexperiment. International Journal of Osteoarchaeology 13: 3745.

Richards MP and Hedges REM (2003) Variations in bone collagen d13C and d15Nvalues of fauna from Northwest Europe over the last 40000 years. Palaeogeography,Palaeoclimatology, Palaeoecology 193: 261267.

Richards MP and Trinkaus E (2009) Isotopic evidence for the diets of EuropeanNeanderthals and early modern humans. Proceedings of the National Academy ofSciences USA 106: 1603416039.

Richards MP, Pettitt PB, Stiner MC, and Trinkaus E (2001) Stable isotope evidencefor increasing dietary breadth in the European mid-Upper Paleolithic. Proceedingsof the National Academy of Sciences of the United States of America98: 65286532.

Richards MP, Pettitt PB, Trinkaus E, Smith FH, Paunovic M, and Karavanic I (2000)Neandertal diet at Vindija and Neandertal predation: The evidence from stableisotopes. Proceedings of the National Academy of Sciences of the United States ofAmerica 97: 76637666.

Richards MP, Taylor G, Steele T, et al. (2008) Isotopic dietary analysis of a Neanderthaland associated fauna from the site of Jonzac (Charente-Maritime), France.Journal of Human Evolution 55: 179185.

Robbins CT, Felicetti LA, and Sponheimer M (2005) The effect of dietary protein qualityon nitrogen isotope discrimination in mammals and birds. Oecologia144: 534540.

Schulze E-D, Chapin FS III, and Gebauer G (1994) Nitrogen nutrition and isotopedifferences among life forms at the Northern treeline of Alaska. Oecologia 100: 406412.

Schwarcz HP, Dupras TL, and Fairgrieve SI (1999) 15N enrichment in theSahara: In search of a global relationship. Journal of Archaeological Science26: 629636.

Smith CI, Craig OE, Prigodich RV, et al. (2005) Diagenesis and survival of osteocalcinin archaeological bone. Journal of Archaeological Science 32: 105113.

Smith CI, Fuller BT, Choy K, and Richards MP (2009) A three-phase liquidchromatographic method for d13C analysis of amino acids from biological proteinhydrolysates using liquid chromatographyisotope ratio mass spectrometry.Analytical Biochemistry 390: 165172.

Smith JM, Lee-Thorp JA, and Sealy JC (2002) Stable carbon and oxygenisotopic evidence for late Pleistocene to middle Holocene climatic fluctuationsin the interior of Southern Africa. Journal of Quaternary Science17: 683695.

van der Merwe NJ and Medina E (1991) The canopy effect, carbon isotoperatios and foodwebs in Amazonia. Journal of Archaeological Science18: 249259.

Wright LE and Schwarcz HP (1998) Stable carbon and oxygen isotopes in Human toothenamel: Identifying breastfeeding and weaning in Prehistory. American Journal ofPhysical Anthropology 106: 118.

314 CARBONATE STABLE ISOTOPES | Terrestrial Teeth and Bones

Terrestrial Teeth and BonesIntroductionPaleobiological Tracking by Isotopes in Teeth and BonesCarbonNitrogenOxygenChronological Resolution of Skeletal TissuesPhysiological Effects (Suckling, Hibernation, Starvation, and Water Stress)

Diagenetic AlterationOrganic FractionMineral Fraction

Reconstruction of Terrestrial PaleoenvironmentsTropical EnvironmentsDevelopment of C4 biomes during the late QuaternaryAridityEcological Flexibility of Large Mammals

Temperate and Boreal EnvironmentsSeasonality

Reconstruction of the Paleobiology of Extinct SpeciesSubsistence Patterns of Ancient HominidsThe importance of savanna for African Pliocene-Pleistocene hominidsThe Diet of Neanderthals and Early Anatomically Modern Humans

Paleodiet of Ancient BearsPaleodiet of Ancient Ungulates

Implications for Late Pleistocene ExtinctionsPerspectivesReferences