Adaptive foraging behaviours in the Horn of Africa during Toba supereruption.

Although modern humans left Africa multiple times over 100,000 years ago, those broadly ancestral to non-Africans dispersed less than 100,000 years ago1. Most models hold that these events occurred through green corridors created during humid periods because arid intervals constrained population movements2. Here we report an archaeological site-Shinfa-Metema 1, in the lowlands of northwest Ethiopia, with Youngest Toba Tuff cryptotephra dated to around 74,000 years ago-that provides early and rare evidence of intensive riverine-based foraging aided by the likely adoption of the bow and arrow. The diet included a wide range of terrestrial and aquatic animals. Stable oxygen isotopes from fossil mammal teeth and ostrich eggshell show that the site was occupied during a period of high seasonal aridity. The unusual abundance of fish suggests that capture occurred in the ever smaller and shallower waterholes of a seasonal river during a long dry season, revealing flexible adaptations to challenging climatic conditions during the Middle Stone Age. Adaptive foraging along dry-season waterholes would have transformed seasonal rivers into 'blue highway' corridors, potentially facilitating an out-of-Africa dispersal and suggesting that the event was not restricted to times of humid climates. The behavioural flexibility required to survive seasonally arid conditions in general, and the apparent short-term effects of the Toba supereruption in particular were probably key to the most recent dispersal and subsequent worldwide expansion of modern humans.

14-Carbon demonstrates that some illegal ivory is being taken from government stockpiles.

The 14-carbon in animal tissues records the time that the tissues are formed; since the 1960s, using the "bomb curve" for 14C, the age of animal death can be determined accurately. Using animal tissue samples of known collection and formation dates for calibration, we determine the age of ivory samples from four ivory seizures made by law enforcement agencies between 2017 and 2019. The 14C measurements from these seizures show that most ivory in the illegal wildlife trade is from animals from recent poaching activities. However, one seizure has a large fraction of ivory that is more than 30 y old, consistent with markings on the tusks indicating they were derived from a government stockpile.

Comparative isotope ecology of western Amazonian rainforest mammals.

Closed-canopy rainforests are important for climate (influencing atmospheric circulation, albedo, carbon storage, etc.) and ecology (harboring the highest biodiversity of continental regions). Of all rainforests, Amazonia is the world's most diverse, including the highest mammalian species richness. However, little is known about niche structure, ecological roles, and food resource partitioning of Amazonian mammalian communities over time. Through analyses of δ13Cbioapatite, δ13Chair, and δ15Nhair, we isotopically characterized aspects of feeding ecology in a modern western Amazonian mammalian community in Peru, serving as a baseline for understanding the evolution of Neotropical rainforest ecosystems. By comparing these results with data from equatorial Africa, we evaluated the potential influences of distinct phylogenetic and biogeographic histories on the isotopic niches occupied by mammals in analogous tropical ecosystems. Our results indicate that, despite their geographical and taxonomic differences, median δ13Cdiet values from closed-canopy rainforests in Amazonia (-27.4‰) and equatorial Africa (-26.9‰) are not significantly different, and that the median δ13Cdiet expected for mammalian herbivores in any closed-canopy rainforest is -27.2‰. Amazonian mammals seem to exploit a narrower spectrum of dietary resources than equatorial African mammals, however, as depicted by the absence of highly negative δ13Cdiet values previously proposed as indicative of rainforests (<-31‰). Finally, results of keratin and bioapatite δ13C indicate that the predictive power of trophic relationships, and traditional dietary ecological classifications in bioapatite-protein isotopic offset expectations, must be reconsidered.

Stable isotopes in hair reveal dietary protein sources with links to socioeconomic status and health.

Carbon and nitrogen isotope ratios in hair sampled from 65 communities across the central and intermountain regions of the United States and more intensively throughout 29 ZIP codes in the Salt Lake Valley, Utah, revealed a dietary divergence related to socioeconomic status as measured by cost of living, household income, and adjusted gross income. Corn-fed, animal-derived proteins were more common in the diets of lower socioeconomic status populations than were plant-derived proteins, with individual estimates of animal-derived protein diets as high as 75%; United States towns and cities averaged 57%. Similar patterns were seen across the socioeconomic status spectrum in the Salt Lake Valley. It is likely that corn-fed animal proteins were associated with concentrated animal-feeding operations, a common practice for industrial animal production in the United States today. Given recent studies highlighting the negative impacts of animal-derived proteins in our diets, hair carbon isotope ratios could provide an approach for scaling assessments of animal-sourced foods and health risks in communities across the United States.

Diets of mammalian fossil fauna from Kanapoi, northwestern Kenya.

Carbon isotope ratios of mammalian teeth from the Kanapoi site in northern Kenya are interpreted in the context of C3 and C4 derived resources to investigate the paleoecology of Australopithecus anamensis. δ13C values of large mammals, when compared at the taxon level, show an ecosystem that is strongly biased towards mixed feeders and browsers. However, sufficient C4 resources were present such that some C4 dominated grazers were also present in the large mammal fauna. Analyses of micromammals shows that their diets were C3 dominated or C3-C4 mixed. Carbon isotope studies of primates shows that the major primate tribes-Colobini, Papioini, Hominini-all made some use of C4 resources in their respective diets; the Hominini had a higher fraction of C3 diet resources than the other primate tribes represented in the fossil record.

Aridity and hominin environments.

Aridification is often considered a major driver of long-term ecological change and hominin evolution in eastern Africa during the Plio-Pleistocene; however, this hypothesis remains inadequately tested owing to difficulties in reconstructing terrestrial paleoclimate. We present a revised aridity index for quantifying water deficit (WD) in terrestrial environments using tooth enamel δ18O values, and use this approach to address paleoaridity over the past 4.4 million years in eastern Africa. We find no long-term trend in WD, consistent with other terrestrial climate indicators in the Omo-Turkana Basin, and no relationship between paleoaridity and herbivore paleodiet structure among fossil collections meeting the criteria for WD estimation. Thus, we suggest that changes in the abundance of C4 grass and grazing herbivores in eastern Africa during the Pliocene and Pleistocene may have been decoupled from aridity. As in modern African ecosystems, other factors, such as rainfall seasonality or ecological interactions among plants and mammals, may be important for understanding the evolution of C4 grass- and grazer-dominated biomes.

Isotopes in teeth and a cryptic population of coastal freshwater seals.

Human activities threaten the biodiversity of aquatic mammals across the globe. Conservation of these species hinges on the ability to delineate movements and foraging behaviors of animals, but gaining such insights is hampered by difficulties in tracing individuals over their lives. We determined isotope ratios in teeth (87 Sr/86 Sr, 13 C/12 C, and 18 O/16 O) to examine lifelong movement and resource-use patterns of a unique freshwater population of a wide-ranging pinniped species (harbor seal [Phoca vitulina]) that resides in Iliamna Lake, Alaska (U.S.A.). This population's potentially unique migratory behavior and use of different trophic resources are unknown. The isotope ratios we measured in teeth showed that seals were born in the lake, remained lifelong residents, and relied principally on resources produced from in the lake, even when seasonally abundant and nutrient-dense spawning anadromous fish (i.e., sockeye salmon [Oncorhynchus nerka]) were available in the lake. Our results illustrate how serial isotope records in teeth, particularly 87 Sr/86 Sr ratios, can be used to quantify how coastal mammal populations exploit both freshwater and marine ecosystems. Understanding lifelong patterns of habitat and resource use is essential information when designing effective conservation plans for threatened coastal mammals. We present the Iliamna Lake harbor seals as a unique case study into how isotope records within teeth can help reveal the cryptic ecology of such a population residing in an intact ecosystem. The results also provide critical baseline information for the Kvichak River system, which is facing an uncertain future due to proposed large-scale industrial development and a rapidly changing climate.

Isotopos Dentales y una Población Críptica de Focas Costeras de Agua Dulce Resumen Las actividades humanas amenazan a la diversidad de mamíferos acuáticos en todo el mundo. La conservación de estas especies depende de la habilidad para delinear los movimientos y los comportamientos de búsqueda de alimento de los animales, pero la obtención de dicha información está obstaculizada por las dificultades en el rastreo de individuos a lo largo del transcurso de sus vidas. Determinamos la proporción de isotopos dentales (87 Sr/86 Sr, 13 C/12 C y 18 O/16 O) para examinar el movimiento a lo largo de la vida y los patrones de uso de recursos de una población única de una especie de pinnípedos de agua dulce con una distribución amplia (foca común [Phoca vitulina]), la cual reside en el lago Iliamna, Alaska (E.U.A.). Se desconocen el comportamiento migratorio potencialmente único de esta población y el uso que le dan a los diferentes recursos tróficos. La proporción de isotopos que medimos en los dientes mostró que las focas nacieron en el lago, permanecieron como residentes de toda la vida y dependieron principalmente de los recursos producidos en el lago, incluso cuando estaban disponibles en aquel lugar por razones reproductivas los peces anádromos abundantes estacionalmente y con densidad de nutrientes (es decir, el salmón rojo [Oncorhynchus nerka]). Nuestros resultados ilustran cómo los registros seriales de isotopos dentales, particularmente la proporción 87 Sr/86 Sr, pueden usarse para cuantificar cómo las poblaciones de mamíferos costeros explotan tanto los ecosistemas marinos como los de agua dulce. El entendimiento de los patrones ontogénicos del uso de recursos y de hábitat es esencial cuando se diseñan planes efectivos de conservación para los mamíferos costeros en peligro. Presentamos a las focas comunes del lago Iliamna como un estudio de caso único sobre cómo los registros de isotopos dentales pueden ayudar a revelar la ecología críptica de dicha población que reside en un ecosistema intacto. Los resultados también proporcionan información importante de línea base para el sistema el río Kvichak, el cual está enfrentando un futuro incierto debido a la propuesta de un desarrollo industrial de gran escala y al rápido clima cambiante.

Radiocarbon dating of seized ivory confirms rapid decline in African elephant populations and provides insight into illegal trade.

Carbon-14 measurements on 231 elephant ivory specimens from 14 large ivory seizures (≥0.5 ton) made between 2002 and 2014 show that most ivory (ca 90%) was derived from animals that had died less than 3 y before ivory was confiscated. This indicates that the assumption of recent elephant death for mortality estimates of African elephants is correct: Very little "old" ivory is included in large ivory shipments from Africa. We found only one specimen of the 231 analyzed to have a lag time longer than 6 y. Patterns of trade differ by regions: East African ivory, based on genetic assignments of geographic origin, has a much higher fraction of "rapid" transit than ivory originating in the Tridom region of Cameroon-Gabon-Congo. Carbon-14 is an important tool in understanding patterns of movement of illegal wildlife products.

Stable isotope ecology of black rhinos (Diceros bicornis) in Kenya.

Stable isotope and elemental ratios in hair are influenced by the environment, including both climate and geology. Stable carbon isotopes can be used to give estimates of the C4/CAM fraction of diets of herbivorous mammals; stable nitrogen isotopes are related to the local water deficit; strontium isotopes are determined by the local geology. We studied hair from rhinos in Kenya to determine spatial patterns in δ13C, δ15N, and 87Sr/86Sr ratios. The samples of rhino hair were collected during Kenya Wildlife Service translocation or veterinary activities. δ13C values showed diets dominated by C3 foods, but in some regions the diet, at least seasonally, contained significant quantities (i.e., > ca. 20%) of C4/CAM foods. δ15N values were related to water deficit, with higher δ15N values in regions with high water deficit. 87Sr/86Sr isotope ratios were found to be related to the local geological substrate suggesting that 87Sr/86Sr isotope ratios are provisionally useful for determining the origins of illegal wildlife materials in Kenya and elsewhere in Africa.

Applying the principles of isotope analysis in plant and animal ecology to forensic science in the Americas.

The heart of forensic science is application of the scientific method and analytical approaches to answer questions central to solving a crime: Who, What, When, Where, and How. Forensic practitioners use fundamentals of chemistry and physics to examine evidence and infer its origin. In this regard, ecological researchers have had a significant impact on forensic science through the development and application of a specialized measurement technique-isotope analysis-for examining evidence. Here, we review the utility of isotope analysis in forensic settings from an ecological perspective, concentrating on work from the Americas completed within the last three decades. Our primary focus is on combining plant and animal physiological models with isotope analyses for source inference. Examples of the forensic application of isotopes-including stable isotopes, radiogenic isotopes, and radioisotopes-span from cotton used in counterfeit bills to anthrax shipped through the U.S. Postal Service and from beer adulterated with cheap adjuncts to human remains discovered in shallow graves. Recent methodological developments and the generation of isotope landscapes, or isoscapes, for data interpretation promise that isotope analysis will be a useful tool in ecological and forensic studies for decades to come.

Environments and trypanosomiasis risks for early herders in the later Holocene of the Lake Victoria basin, Kenya.

Specialized pastoralism developed ∼3 kya among Pastoral Neolithic Elmenteitan herders in eastern Africa. During this time, a mosaic of hunters and herders using diverse economic strategies flourished in southern Kenya. It has been argued that the risk for trypanosomiasis (sleeping sickness), carried by tsetse flies in bushy environments, had a significant influence on pastoral diversification and migration out of eastern Africa toward southern Africa ∼2 kya. Elmenteitan levels at Gogo Falls (ca. 1.9-1.6 kya) preserve a unique faunal record, including wild mammalian herbivores, domestic cattle and caprines, fish, and birds. It has been suggested that a bushy/woodland habitat that harbored tsetse fly constrained production of domestic herds and resulted in subsistence diversification. Stable isotope analysis of herbivore tooth enamel (n = 86) from this site reveals, instead, extensive C4 grazing by both domesticates and the majority of wild herbivores. Integrated with other ecological proxies (pollen and leaf wax biomarkers), these data imply an abundance of C4 grasses in the Lake Victoria basin at this time, and thus little risk for tsetse-related barriers to specialized pastoralism. These data provide empirical evidence for the existence of a grassy corridor through which small groups of herders could have passed to reach southern Africa.

Dietary changes of large herbivores in the Turkana Basin, Kenya from 4 to 1 Ma.

A large stable isotope dataset from East and Central Africa from ca. 30 regional collection sites that range from forest to grassland shows that most extant East and Central African large herbivore taxa have diets dominated by C4 grazing or C3 browsing. Comparison with the fossil record shows that faunal assemblages from ca. 4.1-2.35 Ma in the Turkana Basin had a greater diversity of C3-C4 mixed feeding taxa than is presently found in modern East and Central African environments. In contrast, the period from 2.35 to 1.0 Ma had more C4-grazing taxa, especially nonruminant C4-grazing taxa, than are found in modern environments in East and Central Africa. Many nonbovid C4 grazers became extinct in Africa, notably the suid Notochoerus, the hipparion equid Eurygnathohippus, the giraffid Sivatherium, and the elephantid Elephas. Other important nonruminant C4-grazing taxa switched to browsing, including suids in the lineage Kolpochoerus-Hylochoerus and the elephant Loxodonta. Many modern herbivore taxa in Africa have diets that differ significantly from their fossil relatives. Elephants and tragelaphin bovids are two groups often used for paleoecological insight, yet their fossil diets were very different from their modern closest relatives; therefore, their taxonomic presence in a fossil assemblage does not indicate they had a similar ecological function in the past as they do at present. Overall, we find ecological assemblages of C3-browsing, C3-C4-mixed feeding, and C4-grazing taxa in the Turkana Basin fossil record that are different from any modern ecosystem in East or Central Africa.

Longitudinal and transverse variation of trace element concentrations in elephant and giraffe hair: implication for endogenous and exogenous contributions.

The spatial distribution of trace elements in hair is highly heterogeneous at the microscale. The relatively mild spatial variation of endogenous signal incorporated during hair growth may be amplified by orders of magnitude due to later exogenous contaminations. Here, we studied the longitudinal and transverse distributions of trace elements in elephant and giraffe hair and discussed the possible endogenous and exogenous contributions. Laser ablation ICP-MS analyses were performed on cross sections of hair to assess the surface contamination and transverse variation. We also removed the contaminated surface layer at various distances from hair root of single hair strands using physical abrasion and measured the concentrations by microwave digestion followed by ICP-MS. By comparing the concentrations of 11 trace elements between the intact and abraded hair segments as a function of distance from root and their laser ablation profiles, we rationalized the endogenous and exogenous contributions: Al and Ti concentrations are dominated by the exogenous contamination on the elephant hair surface, probably in the form of insoluble particles, but not in the giraffe hair; Mg, Ca, Sr, Ba, and Mn are enhanced on the elephant hair surface by exogenous contaminations, but a comparable amount was found in the hair interior suggesting migration of these elements from the surface towards the core; Cu, Zn, Se, and Pb did not have surface accumulation and thus were dominated by the endogenous signal. Overall, giraffe hair had minimal surficial contamination, suggesting the origin of its trace elements is predominantly endogenous, except for Mn, which might get contaminated with airborne particles. We thus demonstrate that contamination of hair may be strongly related to behavioral traits and that the interpretation of trace elemental analyses in hair as a biomonitor or for provenance studies would be highly dependent on the species considered.

Reconstruction of travel history using coupled δ18 O and 87 Sr/86 Sr measurements of hair.

RATIONALE: Oxygen isotope ratios (δ18 O values) of hair largely reflect features of regional hydrology while strontium isotope ratios (87 Sr/86 Sr) are thought to reflect bedrock geology; combination of both isotope signatures may provide greater capacity for determining provenance and reconstructing travel history of an organism. To test this hypothesis, we compared the O-Sr isotope profiles of hair from domestic horses with known residency histories. METHODS: Tail hairs were collected from a pair of horses pastured together for a period of 16 months, one of which lived in a different location for the 8 months prior. Hair samples were washed with solvents to remove external contaminants prior to sequential sampling for δ18 O and 87 Sr/86 Sr analysis via TC/EA-IRMS and MC-ICP-MS, respectively. Hair digests were concentrated and analyzed employing low-flow natural aspiration to measure 87 Sr/86 Sr. RESULTS: Tail hair from the control and transported horses had mean δ18 O values of 11.25 ± 1.62 ‰ and 10.96 ± 1.53 ‰, and mean 87 Sr/86 Sr of 0.7101 ± 0.0006 and 0.7109 ± 0.0020, respectively. The δ18 O and 87 Sr/86 Sr profiles for the control and transported horses were indistinguishable when they were pastured together. The 87 Sr/86 Sr profiles were significantly different during the period that the horses were living apart, while the δ18 O values were indistinguishable during that period. CONCLUSIONS: By comparing the O-Sr isotope profiles of a control and transported horse, we investigated isotopic signal(s) potentially useful for reconstructing travel histories via high-resolution sequential sampling along single strands of tail hair. Improved analytical capabilities allowed for extremely low Sr abundance samples to be analyzed for 87 Sr/86 Sr and proved capable of resolving a horse's movement between distinct regions. Copyright © 2017 John Wiley & Sons, Ltd.

Woody cover and hominin environments in the past 6 million years.

The role of African savannahs in the evolution of early hominins has been debated for nearly a century. Resolution of this issue has been hindered by difficulty in quantifying the fraction of woody cover in the fossil record. Here we show that the fraction of woody cover in tropical ecosystems can be quantified using stable carbon isotopes in soils. Furthermore, we use fossil soils from hominin sites in the Awash and Omo-Turkana basins in eastern Africa to reconstruct the fraction of woody cover since the Late Miocene epoch (about 7 million years ago). (13)C/(12)C ratio data from 1,300 palaeosols at or adjacent to hominin sites dating to at least 6 million years ago show that woody cover was predominantly less than ∼40% at most sites. These data point to the prevalence of open environments at the majority of hominin fossil sites in eastern Africa over the past 6 million years.

Stable isotopic variation in tropical forest plants for applications in primatology.

Stable isotope analysis is a promising tool for investigating primate ecology although nuanced ecological applications remain challenging, in part due to the complex nature of isotopic variability in plant-animal systems. The aim of this study is to investigate sources of carbon and nitrogen isotopic variation at the base of primate food webs that reflect aspects of primate ecology. The majority of primates inhabit tropical forest ecosystems, which are dominated by C3 vegetation. We used stable isotope ratios in plants from Kibale National Park, Uganda, a well-studied closed-canopy tropical forest, to investigate sources of isotopic variation among C3 plants related to canopy stratification, leaf age, and plant part. Unpredictably, our results demonstrate that vertical stratification within the canopy does not explain carbon or nitrogen isotopic variation in leaves. Leaf age can be a significant source of isotopic variation, although the direction and magnitude of this difference is not consistent across tree species. Some plant parts are clearly differentiated in carbon and nitrogen isotopic composition, particularly leaves compared to non-photosynthetic parts such as reproductive parts and woody stem parts. Overall, variation in the isotopic composition of floral communities, plant species, and plant parts demonstrates that stable isotope studies must include analysis of local plant species and parts consumed by the primates under study from within the study area. Am. J. Primatol. 78:1041-1054, 2016. © 2015 Wiley Periodicals, Inc.

Diet of Theropithecus from 4 to 1 Ma in Kenya.

Theropithecus was a common large-bodied primate that co-occurred with hominins in many Plio-Pleistocene deposits in East and South Africa. Stable isotope analyses of tooth enamel from T. brumpti (4.0-2.5 Ma) and T. oswaldi (2.0-1.0 Ma) in Kenya show that the earliest Theropithecus at 4 Ma had a diet dominated by C4 resources. Progressively, this genus increased the proportion of C4-derived resources in its diet and by 1.0 Ma, had a diet that was nearly 100% C4-derived. It is likely that this diet was comprised of grasses or sedges; stable isotopes cannot, by themselves, give an indication of the relative importance of leaves, seeds, or underground storage organs to the diet of this primate. Theropithecus throughout the 4- to 1-Ma time range has a diet that is more C4-based than contemporaneous hominins of the genera Australopithecus, Kenyanthropus, and Homo; however, Theropithecus and Paranthropus have similar proportions of C4-based resources in their respective diets.

Bomb-curve radiocarbon measurement of recent biologic tissues and applications to wildlife forensics and stable isotope (paleo)ecology.

Above-ground thermonuclear weapons testing from 1952 through 1962 nearly doubled the concentration of radiocarbon ((14)C) in the atmosphere. As a result, organic material formed during or after this period may be radiocarbon-dated using the abrupt rise and steady fall of the atmospheric (14)C concentration known as the bomb-curve. We test the accuracy of accelerator mass spectrometry radiocarbon dating of 29 herbivore and plant tissues collected on known dates between 1905 and 2008 in East Africa. Herbivore samples include teeth, tusks, soft tissue, hair, and horn. Tissues formed after 1955 are dated to within 0.3-1.3 y of formation, depending on the tissue type, whereas tissues older than ca. 1955 have high age uncertainties (>17 y) due to the Suess effect. (14)C dating of tissues has applications to stable isotope (paleo)ecology and wildlife forensics. We use data from 41 additional samples to determine growth rates of tusks, molars, and hair, which improve interpretations of serial stable isotope data for (paleo)ecological studies. (14)C dating can also be used to calculate the time interval represented in periodic histological structures in dental tissues (i.e., perikymata), which in turn may be used as chronometers in fossil teeth. Bomb-curve (14)C dating of confiscated animal tissues (e.g., ivory statues) can be used to determine whether trade of the item is legal, because many Convention of International Trade of Endangered Species restrictions are based on the age of the tissue, and thus can serve as a powerful forensic tool to combat illegal trade in animal parts.

Stable isotope-based diet reconstructions of Turkana Basin hominins.

Hominin fossil evidence in the Turkana Basin in Kenya from ca. 4.1 to 1.4 Ma samples two archaic early hominin genera and records some of the early evolutionary history of Paranthropus and Homo. Stable carbon isotopes in fossil tooth enamel are used to estimate the fraction of diet derived from C3 or C4 resources in these hominin taxa. The earliest hominin species in the Turkana Basin, Australopithecus anamensis, derived nearly all of its diet from C3 resources. Subsequently, by ca. 3.3 Ma, the later Kenyanthropus platyops had a very wide dietary range--from virtually a purely C3 resource-based diet to one dominated by C4 resources. By ca. 2 Ma, hominins in the Turkana Basin had split into two distinct groups: specimens attributable to the genus Homo provide evidence for a diet with a ca. 65/35 ratio of C3- to C4-based resources, whereas P. boisei had a higher fraction of C4-based diet (ca. 25/75 ratio). Homo sp. increased the fraction of C4-based resources in the diet through ca. 1.5 Ma, whereas P. boisei maintained its high dependency on C4-derived resources.

Carbon isotope ratios of human tooth enamel record the evidence of terrestrial resource consumption during the Jomon period, Japan.

OBJECTIVE: Archaeological remains strongly suggest that the Holocene Japanese hunter-gatherers, the Jomon people, utilized terrestrial plants as their primary food source. However, carbon and nitrogen isotope analysis of bone collagen indicates that they primarily exploited marine resources. We hypothesize that this inconsistency stems from the route of protein synthesis and the different proportions of protein-derived carbon in tooth enamel versus bone collagen. Carbon isotope ratios from bone collagen reflect that of dietary protein and may provide a biased signal of diet, whereas isotope ratios from tooth enamel reflect the integrated diet from all macronutrients (carbohydrates, lipids, and proteins). METHODS: In order to evaluate the differences in inferred diet between the archaeological evidence and bone collagen isotope data, this study investigated carbon isotopes in Jomon tooth enamel from four coastal sites of the Middle to Late-Final Jomon period (5,000-2,300 years BP). RESULTS: Carbon isotope ratios of human teeth are as depleted as coeval terrestrial mammals, suggesting that C3 plants and terrestrial mammals were major dietary resources for the Jomon people. Dietary dependence on marine resources calculated from enamel was significantly lower than that calculated from bone collagen. The discrepancy in isotopic ratios between enamel and collagen and the nitrogen isotope ratio in collagen shows a negative correlation on individual and population levels, suggesting diets with variable proportions of terrestrial and marine resources. CONCLUSION: This study highlights the usefulness of coupling tooth enamel and bone collagen in carbon isotopic studies to reconstruct prehistoric human diet. Am J Phys Anthropol 158:300-311, 2015. © 2015 Wiley Periodicals, Inc.