• Primate Ecology &

    Molecular Anthropology Lab

    University of California Santa Cruz

    Anthropology Department


    Primate Ecology & Molecular Anthropology (PEMA) Lab

    Will Koomijan/emergentreeworks.com

    The PEMA lab at UCSC, which opened in 2018, works at the intersection of isotope biogeochemistry, primatology and archaeology.


    Our research mainly relies on stable isotope analysis (87Sr/86Sr, δ18O, δ15N, δ13C, δ34S, δ66Zn, δ56Fe, δ65Cu) in the study of primate ecology and past human behavior.


    We have a focus on establishing isotope baselines and isoscapes, which are fundamental to most isotope projects.



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    We also employ direct observations and camera traps to study primate behavior in the wild, as well as rope based tree climbing for arboreal sample collection.

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    • strontium extraction from skeletal remains, plants, mollusks and soil in clean lab setting
    • collagen extraction from bone/dentin
    • tooth enamel prep for 87Sr/86Sr, δ18O and δ13C analyses
    • processing of primate hair and feces meeting bio-safety standards (BSL 2)
    • enamel silver phosphate extraction (δ18O)
    • microscopy

    picture by Vicky Oelze at Elkhorn Slough



    Land Acknolwegement by the PEMA lab:

    “The land on which we work at UCSC is the unceded territory of the Awaswas-speaking Uypi Tribe. The Amah Mutsun Tribal Band, comprised of the descendants of indigenous people taken to missions Santa Cruz and San Juan Bautista during Spanish colonization of the Central Coast, is today working hard to restore traditional stewardship practices on these lands and heal from historical trauma.”


    The origins and life histories of enslaved Africans from Lagos (Portugal) revealed by multi isotope analysis

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    Meet our international team!


    Thanks to generous funding by the National Geographic Society we were able to welcome five incredible students from Portuguese universities to the team working on the human remains from Valle da Gafaria, investigating these individuals' life histories and African roots via stable isotope analysis.


    Students are from the fields of forensic anthropology, bioarcheology, archaeology and primatology with roots in Brazil, Guinea-Bissau, Nigeria, Portugal, and Spain. Later in the summer, another UCSC alumni with a background in forensics as well as our PostDoc Xueye joined the group to assist with the stable isotope sample preparation at UCSC.

    The team working together at UCSC; photo from left to right:

    Carina Leirião, Naima Tucker, Ana González Ruiz, Xueye Wang, Toto, Vicky Oelze, Joseph Babatunde Ogunsetire, Luis Sanca, Luiza Báo Sobreira



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    Our initial 2 week sampling fieldwork commenced in June 2022 at the Anthropology Department of the University of Coimbra, with 5 students and the Co-PIs Maria Teresa Ferreira and Sophia Wasterlain. Students were trained in sampling of human tooth enamel and dentin, briefed in lab safety and their rights and obligations as project members. We successfully sampled tooth enamel and dentin from all human remains with preserved dentition recovered from Valle da Gafaria. We also held lectures on the archaeology of Valle da Gafaria and the bioarcheology of the human remains, as well as on stable isotope ecology.

    In August 2022, the students came to California and spent almost 2 weeks in the PEMA lab at UCSC to process all ~120 dental samples for multiple isotope analysis. We extracted collagen from dentin samples using the ultracentrifugation method, weighed collagen vor δ13C and δ15N analysis and enamel samples for δ18O and δ13C analysis, and prepared enamel samples for 87Sr/86Sr analysis in the clean lab facilities of the Keck lab.

    Further, we had engaging guest lectures on the History of the Transatlantic Slave Trade (Greg O'Malley, UCSC) the Archaeology of Slavery and the African Diaspora (Cameron Monroe, UCSC), and highly informative lab tours in the Stable Isotope Lab by Colin Carney and of the Keck Isotope Facility by Terry Blackburn (see images below). Many thanks to all speakers for spending time with us, we appreciate you sharing your knowledge!

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    Project Background

    The archaeological site of Valle da Gafaria in Lagos is known as the earliest and largest burial site of enslaved Africans ever found in Europe, predating one of the most shameful chapters of Western history, the Transatlantic slave trade. Bioarchaeological evidence obtained from a total of 158 individuals proves they were of African origin and forcefully deported to Lagos in the 15th to 17th centuries. However, the African regions they were abducted from remain unknown. This makes it difficult to connect them with descendant communities today and to assess Portugal’s early collusion in the slave trade.

    Multiple stable isotope analysis has the potential to address questions regarding the African origins and dramatic shifts in lifestyles of the individuals discovered at Valle da Gafaria as isotope ratios are incorporated into forming skeletal tissues and can be associated with specific dietary customs (carbon, nitrogen, sulfur), environments (carbon, sulfur), climate/geographic region (oxygen) and geological location (strontium), and hence overall life conditions. Sampling small amounts of dental tissue, which reflect early (1st molar enamel) and later childhood (1st molar root) as well as adolescence (3rd molar enamel) and early adulthood (3rd molar roots), allows us to trace how living conditions changed through a person’s early life.


    We will measure these isotopes in teeth from the human remains from Valle da Gafaria in collaboration with our Portuguese colleagues and our international team of students to reconstruct individual human origins and to document the rapid changes in life conditions as the result of forced migration from West and Central Africa to Portugal. Isotopic similarities between individuals may suggest they are of common origin. We will also consult complimentary evidence such as dental modifications and signs of nutritional stress as well as the factors age and sex when reconstructing individual life histories.


    This project is supported by and consulting with members of Djass - Associação de Afrodescendentes to actively include the voices of members of the afrodescendant community in Portugal into this project and the dissemination of our findings.

  • TEAM

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    Dr. Vicky M. Oelze

    associate professor, lab PI

    lab director anthropology department

    Picture by Vicky Oelze

    Renee Boucher

    PhD student


    picture by Kyle Sweeney

    Seth Phillips

    PhD student



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    Elyse Venerable

    undergraduate researcher


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    Halena Soto

    undergraduate researcher


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    Chloe Brudney

    undergraduate researcher


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    Kayla Ott

    lab manger

    for all anthropology laboratories


    picture by Virgile Manin




    does not check his emails regularly

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    chimp video coding team

    undergraduate student

    cohort 2022-2023

    CJ King, Tyler Clark, Nicola Luna Cervantes, Chloe Brudney, Jahon Shapouri, Gabby Martinez, Mia Guiste, Sara Nordeen, Sophia Lewis-Mussa, Jenna Dinapoli


    our current research endeavors and the people behind them

    picture by G. Bocksberger

    Pan African Strontium Isoscape

    Vicky M. Oelze with Xueye Wang and Gaelle Bocksberger

    The analysis of the stable isotopes of strontium (87Sr/86Sr) is a well-established tool in archaeological science to trace back the geological origin of an organism, e.g. where a person was born and raised. Several studies have measured the 87Sr/86Sr values in the remains of humans subjected to slavery in the Americas. However, these studies were largely unable to pinpoint human origins beyond the identification that some individuals must have been born somewhere in Africa because spatial bioavailable 87Sr/86Sr data barely exists for Sub-Saharan Africa. Environmental strontium isotope mapping of West and Central Africa can provide a solid foundation for future forensic investigations of historic human displacement during the transatlantic slave trade. This new map will also be relevant for wildlife forensics, as isotopes are a increasingly used method to identify hotspots of illegal poaching activity. This project has the potential to be have significant impact on the archaeology of Africa and the transatlantic slave trade, as well as for wildlife conservation. We are looking forward to possibly extending this project to sulfur, oxygen and possibly lead isotope data in the future.


    We are generously funded through the Webster Foundation and are collaborating on this project with the Pan African Programme (http://panafrican.eva.mpg.de/), former Primatology Department, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany, as well as many collaborating botanist and archaeologists worldwide.

    Oyo empire_Alaafin Oyo c. 1910 Colorized

    The origins of the Oyo Empire war horses

    Elyse Venerable and Vicky M. Oelze

    The Oyo was an important Yoruba Empire of the 17th and 18th centuries, located in what is today Nigeria and Benin. The use of horses and ponies in warfare was a key aspect of the Oyo army and the empires expansion in West Africa. The origin of this unusual cavalry is yet unclear, as it is commonly difficult to breed horses in this part of West Africa due to the tropical conditions and associated pathogens. The largest assemblage of such war equids was discovered in Ede-Ile in Nigeria, which was home to the royal court of Oyo (Ogundiran 2012), which provides a unique opportunity to empirically assess where these horses were imported from. In this study, we conduct strontium isotope analysis in archeological horse teeth (n=37) from 26 individuals to establish if these horses were indeed imported from within Oyo (Northern Nigeria) or from other places within the Sahel Zone. By sampling eraly and late forming teeth in 11 horses, we can assess the age at which they were brought to Ede-Ile.


    We are closely collaborating on this project with Akin Ogundrian (Northwestern University), William Taylor and Olumide Ojediran (University of Colorado Boulder)

    presenting at the AABAs in Los Angeles 2024

    Chimpanzee and mountain gorilla weaning behavior

    Halena Soto, Chloe Budney and Vicky M. Oelze

    Weaning from breastmilk and the transition to solid foods marks a significant milestone in the early life history of primates and other mammals. Stable isotope analysis of feces from mother-offspring dyads allows for non-invasively estimating nutritional weaning in wild primate populations. In this project we are collaborating closely with colleagues studying the eraly ontogeny of the Gombe chimpanzees and the Karisoke mountain gorillas to estaimate weaning ages in these two great ape populations using fecal iostope analsysis.


    We are collaborating on this project with Shannon McFarlin, Elisabeth Lonsdorf and Martha Robbins, among others.

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    Cu, Fe, Zn and Sr isotopes as bio-markers of human

    and non-human primate life history

    Renee Boucher, Vicky M. Oelze and Paul Koch

    While Strontium isotopes (87Sr/86Sr) have been used for two decades to reconstruct the mobility patterns of prehistoric people and even fossil hominins, the isotopic measurement of other elements with large mass have only more recently become technically feasible to be of use in anthropology. Initial work on Copper and Iron stable isotope ratios (δ56Fe, δ65Cu) suggests that there are significant differences between human males and females, presumably due to different metabolism and function of these elements in female reproductive physiology. The isotope ratios of Zink (δ66Zn) measured in tooth enamel have recently been described to correspond to the trophic level in the food web, making this element potentially extremely valuable for paleodietary reconstructions in fossils. We measure in enamel samples from the Tai chimpanzee skeletal collection to reconstruct female mobility and potentially identify the areas to which they were native. We measure δ56Fe and δ65Cu values to explore how these isotope systems between male and female chimpanzees to test the utility of this approach to differentiate between the sexes in other large bodied primates such as fossil hominoids. Finally we test the use of δ66Zn in enamel of wild chimpanzees to address questions of tropic level and meat consumption, where nitrogen isotopes yielded contradicting results.


    We are collaborating with Roman Wittig (Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany), Klervia Jaouen (Géosciences Environnement, Toulouse, France), and Linda Godfrey (Rutgers University)

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    South African hunter-gatherer mobility revealed through strontium isotope analysis

    collaboration with Patricia McNeil and Teresa Steel (UC Davis), and Vicky M. Oelze

    We are collaborating with faculty members and graduate students from the Evolutionary Anthropology Wing of the Anthropology Department at UC Davis on middle paleolithic hunter-gatherer mobility and the use and transport of ostrich eggshell using strontium isotopes (87Sr/86Sr) and building local strontium isoscapes.




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    Changes in crop management in prehistoric South Korea

    Vicky M. Oelze, Brynn Lowry & Gyoung-Ah Lee

    Together with archaeobotanist Lee we use stable isotope analysis to examine how ancient agricultural management practices in raised field farming have changed over time at the archaeological site of Pyeonggeodong in south-central South Korea. Alongside radiocarbondating, are analyzing the carbon and nitrogen stable isotope ratios in individual charred macoremains of barley (Hordeum sativum), wheat (Triticum aestivum), foxtail millet (Setaria italica), broomcorn millet (Panicum millaceum) and rice (Oryza sativa), as well as soy (Grycine max ssp.) and azuki beans (Vigina angluris). These specimen date to the Neolithic Chulmun period (~5000 calBP), the Bronze Age, Three Kingdom Period to the Goryeo Dynasty (~1000-500 calBP). We are specifically interested in how irrigation and manuring strategies have changed over time as farming transitioned from millet and azuki production to a larger diversity of cereals.


    We are collaborating on this project with Gyoung-Ah Lee (Anthropology Department, University of Oregon) https://anthropology.uoregon.edu/profile/galee/

    picture by Niina Nurmi (LuiKotale Bonobo Project)

    bonobo weaning behavior

    Vicky M. Oelze

    Weaning, the process from breastfeeding to solid food intake in infants, is an important and critical phase in primate ontogeny which is extremely difficult to monitor in elusive wild primate species. Particularly in great apes such as bonobos (Pan paniscus), observations on breastfeeding and weaning are limited due to the arboreal nature of this species. Stable isotope analysis has proven to be a powerful tool to assess changes in diets of elusive animals over time. In this project, we employ stable isotope analysis to indirectly and non-invasively monitor the process of ceasing breastmilk in the diet of wild infant bonobos by analyzing fecal samples from wild bonobos of the LuiKotale Bonobo Project in the Democratic Republic of Congo. By monitoring the weaning process throughout infant ontogeny in males and females, we will be able to address questions on sex biased maternal investment in wild bonobos.


    This project is a collaborative venture between the PEMA lab, Barbara Fruth and Gottfried Hohmann representing the LuiKotale Bonobo Project. While our first findings will be published soon, this is an on-going long-term project with more data on inter-individual variation in weaning ages in the pipeline.

    picture by Kyle Sweeney

    chimpanzee termite fishing ecology

    Seth Phillips, advised by Vicky Oelze

    Seth is studying the relationship between chimpanzees and Macrotemes termites in the Isaa valley of Tanzania. He investigates how much of the termites' complex ecology and reproductive cycle effects the chimpanzees ability to successfully fish for termites across the seasons. How do chimpanzees know when it is a good day to fish? And how do termites respond to predation by chimpanzees and does that vary over time?


    Seth will examine whether the swarming behavior of the Macrotermes alates provides an ephemeral opportunity for chimpanzees to effectively termite-fish at Issa and beyond. Seth will experimentally replicate termite-fishing behavior at a selection of Macrotermes mounds. From long-term camera trap footage Seth will additionally assess the timing, the duration/intensity and the mode of chimpanzees visiting and re-visiting termite mounds. Read and see more about his field experience at Issa Valley here.


    We are collaborating on this project with Alex Piel and the GMERC (http://gmerc.org/). Seth finished his disseration and received his PhD in June of 2024!

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    "A bite of chimp habitat" - dental proxies for habitat in extant chimps

    Vicky M. Oelze with the PanAf and the MPWC

    Stable isotope ratios have been measured in a range of fossil teeth from early African hominins and great apes from Africa and Asia. Isotope data suggests that many fossil hominin taxa in Africa were adapted to open environments and depended highly on C4 plant food resources. Although savanna chimpanzees are frequently used to model the ecology of these fossil species based on the biochemistry of their tooth enamel, there is little dental enamel isotope data from different chimpanzee populations, and none from those inhabiting savanna woodlands, more similar to environments presumably inhabited by fossil hominins. The same can be said about dental microtexture analysis. We close these gaps by providing a combined carbon and oxygen isotope and dental microwear dataset from forest and savanna chimpanzees and by integrating comprehensive information on their habitats. We predict that canopy cover and habitat density will be differently be reflected in dental carbon and oxygen stable isotope ratios. Differences in the biomechanical properties of plant foods between savanna and forest habitats (van Casteren et al. 2018) will also be reflected in distinct microtexture patterns. By integrating detailed habitat and climate information to the dental ecology data we will provide a completely new framework for the interpretation of isotopic and microwear data from fossil primates, including hominins.


    Project PI Vicky Oelze (UCSC), with Gaelle Bocksberger (PanAf, MPI-EVA), Ellen Schulz-Kornas, Kornelius Kupczik and Adam van Casteren (MPWC and MPI-EVA).

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    the demographics of termite fishing chimpanzees

    Vicky M. Oelze and Victoria Collins

    Wild chimpanzees across Africa fish for termites using complex tool kits made of sticks or other parts of vegetation. We still little understand how this complex cultural behavior and knowledge is transferred from one generation to the next via social learning. Using camera trap footage data from the Issa chimpanzees (GMERC), assistant Victoria Collins is investigating sex differences in chimpanzee termite mount visitation rates and how long females stay actively fishing at termite mounts compared to males, particularly when they are with their dependent offspring.


    We are collaborating on this project with Alex Piel and the GMERC (http://gmerc.org/).


    latest update 7/2024

    In the pipeline

    Wang X., Bocksberger G., Agbor A., Angedakin S., Aubert F., Ayuk Ayimisin E., Bailey E., Barubiyo D., Bessone M., Bobe R., Bonnet M., Boucher R., Brazzola G., Brewer S., Lee K., Carvalho S., Chancellor R., Cipoletta C., Cohen H., Copeland S.R., Corogenes K., Costa A.M., Coupland C., Curran B., de Ruiter D.J., Deschner T., Dieguez P. ,Dierks K., Dilambaka E., Dowd D., Dunn A., Ebot Egbe V., Finckh M., Fruth B., Gijanto L., Ginath Yuh Y., Goedmakers A., Gokee C., Gomes Coelho R., Goodman A.H., Granjon A-C., Grimes V., Grueter C.C., Haour A., Hedwig D., Hermans V., Hernandez-Aguilar R.A., Hohmann G., Imong I., Jeffery K., Jones S., Junker J., Kadam P., Kambere M., Kambi M., Kienast I., Knudson K.J., Langergraber K.E., Lapeyre V., Lapuente J., Larson B., Lautenschlaeger T., le Roux P., Leinert V., Llana M., Logan A., Lowry B., Lüdecke T., Maretti G., Marrocoli S., Martín R., McNeill P.J., Meier A.C., Meller P., Monroe J.C., Morgan D., Mulindahabi F., Murai M., Neil E., Nicholl S., Niyigaba P., Normand E., Ormsby L.J., Orume R., Pacheco L., Piel A., Preece J., Regnaut S., Richard F.G., Richards M.P., Rundus A., Sanz C., Sommer V., Sponheimer M., Steele T.E., Stewart F.A., Tagg N.. Tédonzong L, Tickle A., Toubga L., van Schijndel J., Vergnes V., Wangue Njomen N., Wessling E.G., Willie J., Wittig R.M., Yurkiw K., Zipkin A.M., Zuberbühler K., Arandjelovic M., Kühl H.S., Boesch C., Oelze V.M. (in review). Strontium isoscape of sub-Saharan Africa allows tracing origins of victims of the transatlantic slave trade. Nature Communications


    Phillips S., Sime P., de la Rosa C., Whelan J., Piel A.K., Stewart F., Oelze V.M. (in review): Wild Chimpanzees utilize use rainfall as a cue to inspect termite mounds for fishing. Scientific Reports


    Wang X. , Li K., Wei D., Zhang G., Hu X., Feng J., Jiao Y., Xu B., Qin X., Oelze V.M., Tang Z. (in review): Diet along the ancient Silk Roads: An isotopic case study of human and livestock from the Han-Jin Dynasties in the Lop Nur Region, northwest China. Archaeological and Anthropological Sciences


    Boucher R., Jaouen K., Wittig R.M., Koch P.L., Oelze V.M. (submitted): Zinc isotope ratios (δ66Zn) suggest a sex difference in diet among wild chimpanzees (Pan troglodytes verus). American Journa of Biological Anthropology.


    Taylor, W T. T. , Delsol N., Mitchell P., Stricker L. Lavin, M.D., Givens D., Ogundiran A., Oelze V.M., Hosek L., Barrón-Ortiz C.I., Olumide Ojediran O., Quintero-Bisono D., Magoon D., Hill, Jr M.E., Thomas A.E., Waterman A., Peate D., Chauvey L., Schiavinato S., Tonasso-Calvière L., Borges L., Brito-Mayor A., Santana J., Kamenov G., Orlando L., Krigbaum J. (submitted): Early transatlantic movement of horses and donkeys at Jamestown. PNAS


    Wang X.*, Watson J.*, Bennett H., Nowell G., Peterkin J., Pike A., Pearson A., Robson Brown K., Laffoon J., Oelze V.M.*, Schroeder H.* (in prep.): Isotopic evidence for the origins of St Helena's liberated Africans. (* shared first or shared correspondng/senior authorship)


    Zihua Tang, Xueye Wang, Dong Wei, Kangkang Li, Qiaomei Fu, Chao Ning, Xingjun Hu, Wenying Li, Idilisi Abuduresule, Xiaoguang Qin, Yinqiu Cui, Shiling Yang, Vicky M. Oelze, Robert N. Spengler, Patrick Roberts (in prep.) Isotopic evidence for dynamic adaptations to climate change and desertification in the Bronze Age Tarim Mummies of Xiaohe.


    McNeill P.J., Wang X., Mackay A., Oelze V.M., Teresa E. Steele T.E.: (in prep.): Ostrich Habitat Use and Past Human Mobility Revealed by Sr Isotope Analysis


    Lee G-A., Lowry B., Oelze V.M. (in prep.): Stable isotope, radiocarbon and archaeobotanical evidence for several millennia of continuity in farming practices at the site of Pyeonggeodong, South Korea.


    Bocksberger G., Schulz-Kornas E., van Casteren A., Dieguez P., Agbor A., Deschner T., Goedmakers A., Granjon A-C., Kadam P., Kambi M., Leinert V., Meier A.C., Lapuente J., Piel A., Van Schijndel J., Sommer V., Stewart F., Ton E., Wittig R.M., Krüger S., Kupczik K., Arandjelovic M., Boesch C., Kühl H.S., Oelze V.M. (in prep.): Dental paleoproxies in extant chimpanzees (Pan troglodytes) relate to climate and vegetation characteristics across tropical Africa.



    Oelze V.M., Ott K., Lee S., O’Neal I., Hohmann G., Fruth B. (accepted manuscript): The first isotopic assessment of weaning age in wild bonobos (Pan paniscus) shows evidence for extended breastfeeding, sibling competition and invested first-time mothers. American Journal of Primatology


    Boucher R., Wittig, R., Lemoine S.T., Maro, A., Wang, X., Koch, P., Oelze V.M. (2024): Strontium isotopes track female dispersal in Taï chimpanzees. American Journal of Biological Anthropology. https://doi.org/10.1002/ajpa.24981



    Phillips S., Piel A., Stewart F., Oelze V.M. (2023): A chimpanzee's time to feast: Seasonality of Macrotermes flight hole activity and alate dispersal flights detected by termite-fishing experiments and camera traps in the Issa Valley, Tanzania. Frontiers in Ecology and Evolution 11, https://doi.org/10.3389/fevo.2023.1289433 


    Zihua Tang, Z. & Wang, X. (2023): A score of bioavailable strontium isotope archaeology in China: Retrospective and prospective. Frontiers in Earth Science 10, https://doi.org/10.3389/feart.2022.1094424


    Wang X., Bockberger G., Lautenschläger T., Finckh M., Meller P., O'Malley G.E., Oelze V.M. (2023): A bioavailable strontium isoscape of Angola and with implications for reconstructions of the Transatlantic Slave Trade. Journal of Archaeological Science Volume 154, , 105775, https://doi.org/10.1016/j.jas.2023.105775 


    Oelze V.M., O’Neil I., Wittig R. M., Kupczik K., Schulz-Kornas E., Hohmann G. (2022): A skew in poo: Biases in primate fecal isotope analysis and recommendations for standardized sample preparation. American Journal of Primatology, e23436. https://doi.org/10.1002/ajp.23436 


    Nicklisch N., Oelze V.M., Schierz O., Meller H., Alt K.W. (2022): A healthier smile in the past? Dental health and diet in Early Neolithic farmer communities from Central Germany. Nutrients. 14(9), 1831. https://www.mdpi.com/2072-6643/14/9/1831


    D’Ammando G., Caro, T., Oelze V.M., Phillips S., Sime P., Stewart F.A., Piel A.K. (2022): Ecological drivers of habitat use by small mammals in a miombo ecosystem. Frontiers in Ecology and Evolution, 10, https://doi.org/10.3389/fevo.2022.773568


    Washburn E., Ibarra B., Titelbaum A.R., Fehren-Schmitz L., Nesbitt J., Oelze V.M. (2022): A multi-isotope approach reconstructing human residential mobility and diet during the Late Intermediate Period (AD 1000-1450) in highland Ancash, Peru. Journal of Archaeological Science - Reports 41, 103291 https://www.sciencedirect.com/science/article/pii/S2352409X21005034?dgcid=coauthor


    Lowry, B.E., Wittig, R.M., Pittermann J., Oelze, V.M. (2021): Stratigraphy of stable isotope ratios and leaf structure within a tropical rainforest canopy in West Africa: Implications for primate feeding and isotope ecology. Scientific Reports 11, 14222. https://www.nature.com/articles/s41598-021-93589-8


    Boucher R.D., Alavi S.E., De Jong H.N., Godfrey L. V., Vogel E.R. (2021): Copper (Cu) and iron (Fe) stable isotope evidence as an indicator of sex in mature rhesus macaques (Macaca mulatta). American Journal of Physical Anthropology. https://onlinelibrary.wiley.com/doi/full/10.1002/ajpa.24301


    Washburn E., Nesbitt J., Ibarra B., Fehren-Schmitz L., Oelze V.M. (2021): A strontium isoscape for the Callejon de Conchucos region of highland Peru and its application to Andean archaeology. PLoS ONE 16(3): e0248209. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0248209


    Phillips S., Scheffrahn R.H., Piel A., Stewart F., Agbor A., Brazzola G., Tickle A., Sommer V., Dieguez P., G. Wessling E.G., Arandjelovic M., Kühl H., Boesch C., Oelze V.M. (2021): Limited evidence of C4 plant consumption in mound building Macrotermes termites from savanna woodland chimpanzee sites. PlosOne. PLoS ONE 16(2): e0244685. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0244685



    Oelze, V. M., Wittig R.M., Lemoine S., Kuehl H.S., Boesch C. (2020): How isotopic signatures relate to meat consumption in wild chimpanzees: A critical reference study from Taï National Park, Côte d’Ivoire. Journal of Human Evolution 146, 102817



    Oelze, V. M., Percher A., Nsi Akoué G. , El Ksabi N., Willaume E. , Charpentier M.J.E. (2020): Seasonality and inter-individual variation in mandrill feeding ecology revealed by stable isotope analyses of hair and blood. American Journal of Primatology 82 (12), https://doi.org/10.1002/ajp.23206



    Washburn, E., Tomasto E., Nesbitt J., Burger R, Oelze V.M., Fehren-Schmitz L (2020): Carbon and nitrogen isotopic evidence of diet among individuals interred at the Late Preceramic Period/Initial Period Site of La Galgada, Peru. Journal of Archaeological Science- Reports 31, 102309



    Wessling E.G., Oelze V.M., Eshuis H., Pruetz J.D., Kühl H.S. (2019): Stable isotope variation in savanna chimpanzees (Pan troglodytes verus) indicate avoidance of energetic challenges through dietary compensation at the limits of the range. American Journal of Physical Anthropology, 168 (4), 665-675. DOI:10.1002/ajpa.23782




    van Casteren A., Oelze, V.M., Angedakin S., Kalan A.K., Kambi M., Boesch C., Kuehl H.S., Langergraber K.E., Piel A.K., Stewart F.A., Kupczik K. (2018): Food mechanical properties and isotopic signatures in forest versus savannah dwelling eastern chimpanzees. Communications Biology 1 (1), #109


    Muenster A., Knipper C., Oelze V.M., Nicklisch N., Stecher M., Schlenker B., Ganslmeier R., Fragata M., Friederich S., Dresely V., Hubensack V., Brandt G., Doehle J., Vach W., Schwarz R., Metzner-Nebelsick C., Meller H., Alt K.W. (2018): 4000 years of human dietary evolution in Central Germany, from the first farmers to the first elites. PlosOne. https://doi.org/10.1371/journal.pone.0194862



    Scheffrahn, R.H., Bourguignon T., Bordereau C., Hernandez-Aguilar R.A., Oelze V.M., Dieguez P., Sobotnik, J., Pascual-Garrido, A. (2017): White-gutted soldiers: simplification of the digestive tube for a non-particulate diet in higher Old World termites (Isoptera: Termitidae). Insectes Sociaux,1-9.



    Oelze, V. M., Fahy, G. E., Hohmann, G., Robbins, M. M., Leinert, V., Lee, K., Eshuis, H., Seiler, N., Wessling, E. G., Head, J. S., Boesch, C., & Kuehl, H. S. (2016). Comparative isotope ecology of African great apes. Journal of Human Evolution, 101, 1-16.


    Crowley, B., Reitsema, L., Oelze, V. M., & Sponheimer, M. (2016). Advances in primate stable isotope ecology-achievements and future prospects. American Journal of Primatology, 78(10), 995-1003.


    Special Issue in the American Journal of Primatology, co-edited by Brooke E. Crowley, Laurie J. Reitsema, Vicky M. Oelze and Matt Sponheimer (2016): "Advances In Primate Stable Isotope Ecology"


    Mundry, R., and Oelze, V. M. (2016). Who is who matters - the effects of pseudoreplication in stable isotope analysis. American Journal of Primatology, 78(10), 1017-1030.


    Oelze, V. M. (2016). Reconstructing temporal variation in great ape and other primate diets: A methodological framework for isotope analyses in hair. American Journal of Primatology, 78(10), 1004-1016.


    Oelze, V. M., Douglas, P. H., Stephens, C. R., Behringer, V., Surbeck, M., Richards, M. P., Fruth, B., & Hohmann, G. (2016). The steady state great ape? Long term isotopic records reveal the effects of season, social rank and reproductive status on bonobo feeding behaviour. PlosOne, 11(9): e0162091.



    Oelze, V. M., Head, J. S., Robbins, M. M., Richards, M. P., & Boesch, C. (2014). Niche differentiation and dietary seasonality among sympatric gorillas and chimpanzees in Loango National Park (Gabon) revealed by stable isotope analysis. Journal of Human Evolution, 66(1), 95-106.


    Nehlich, O., Oelze, V. M., Jay, M., Conrad, M., Staeuble, H., Teegan, W.-R., & Richards, M. P. (2014). Sulphur isotope ratios of multi-period archaeological skeletal remains from central Germany: A dietary and mobility study. Anthropologie: international journal of the science of man, 52(1), 15-33.



    Oelze, V. M., Nehlich, O., & Richards, M. P. (2012). "There's no place like home" - No isotopic evidence for mobility at the Early Bronze Age cemetery of Singen, Germany. Archaeometry, 54(4), 752-778.


    Oelze, V. M., Koch, J. K., Kupke, K., Nehlich, O., Zaeuner, S., Wahl, J., Weise, S. M., Rieckhoff, S., & Richards, M. P. (2012). Multi-isotopic analysis reveals individual mobility and diet at the Early Iron Age Monumental Tumulus of Magdalenenberg, Germany. American Journal of Physical Anthropology, 148(3), 406-421.


    Deschner, T., Fuller, B. T., Oelze, V. M., Boesch, C., Hublin, J.-J., Mundry, R., Richards, M. P., Ortmann, S., & Hohmann, G. (2012). Identification of energy consumption and nutritional stress by isotopic and elemental analysis of urine in bonobos (Pan paniscus). Rapid Communications in Mass Spectrometry, 26(1), 69-77.


    Oelze, V. (2012). Mobility and diet in Neolithic, Bronze Age and Iron Age Germany: evidence from multiple isotope analysis. PhD Thesis, Department of Human Origins, Faculty of Archaeology, Leiden Univ., Leiden.



    Oelze, V. M., Fuller, B. T., Richards, M. P., Fruth, B., Surbeck, M., Hublin, J.-J., & Hohmann, G. (2011). Exploring the contribution and significance of animal protein in the diet of bonobos by stable isotope ratio analysis of hair. Proceedings of the National Academy of Sciences of the United States of America, 108(24), 9792-9797.


    Oelze, V. M., Siebert, A., Nicklisch, N., Meller, H., Dresely, V., & Alt, K. W. (2011). Early Neolithic diet and animal husbandry: stable isotope evidence from three Linearbandkeramik (LBK) sites in Central Germany. Journal of Archaeological Science, 38(2), 270-279.



    meet our collaborators and their projects

    picture by Alex Piel

    Greater Mahale Ecosystem Research and Conservation (GMERC)

    (formerly Ugalla Primate Project)

    We are collaborating with GMERC on numerous projects on chimpanzee termite fishing behavior, termite ecology and camera trap data. The GMERC project is located in the savanna/Miombo woodland landscape of the Issa Valley in Tanzania, East Africa. Research at GMERC focuses on the behavior, ecology, and conservation of the wildlife and especially primates that live across the Greater Mahale Ecosystem.

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    Taï Chimpanzee Project (TCP)

    Since 2015, Vicky Oelze is collaborating with TCP on the stable isotope ecology of the Taï chimpanzees and Taï forest. Our main interest is the relationship between meat eating behavior in the Taï chimpanzees and the stable isotope ratios (C, N, Zn) of hair and skeletal tissues (enamel, bone), but also the exploration of novel stable isotope systems such as Fe and Cu. The Taï Chimpanzee Project is located in Côte d’Ivoire, West Africa, and has been established about 40 years ago by Christophe and Hedwige Boesch. Today the project is co-directed by Roman Wittig and Catherine Crockford and is following three habituated neighboring communities of chimpanzees.

    Photo by Caroline Deimel

    LuiKotale Bonobo Project

    Since 2009, Vicky Oelze is collaborating with Gottfried Hohmann and Barbara Fruth on the isotope ecology of the LuiKotale bonobos. This collaboration is still ongoing with a current project on bonobo infant weaning behavior. The site, with today 2 habituated bonobo groups and another under habituation, is located close to the Western border of Salonga National Park in DRC, which belongs to the largest remaining forest blocks in Africa.

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    UCSC Isotope Facilities

    We measure our stable isotope samples on the UCSC campus either in the Stable Isotope Lab (C, N, S, O)


    or in the Keck Lab (Sr)


    picture by Vicky Oelze

    Emergent Treeworks

    Research on the ecology of living primates can get a very different perspective if one is high up in the trees. Trust us, it's a fact! Will Koomjian, certified arborist, tree climber, and undisputed tree nerd, instructs and assists researchers worldwide in accessing the crowns of the canopy for their projects. Will worked with Vicky in Taï National Park in 2015. In the field season of 2017, Vicky worked with another stellar arborist, the late James Luce who passed away in summer 2020 and is dearly missed. The publication Lowry et al. (2021) is dedicated to James. (https://www.arborcanada.com/instructors/Luce-James/)

  • teaching

    Classes in and around the lab

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    Evolution of Human Diet

    fall quarters of 2017, 2018, 2020, 2022, 2023, summer session 2021, coming up again fall 2025


    This lecture discusses the evolution of human diet and subsistence from a biological anthropological perspective, including evidence on past human behaviors revealed by paleoanthropology, archaeology, archaeometry, primatology, genetics and osteology. It will introduce the students to the main hypothesis related to the evolution of dietary behavior from our early ancestors up to the transition to agriculture and animal husbandry, from man the hunted - to man the hunter - to man the cook – to man the farmer.


    ANTH 106

    Primate Behavior & Ecology

    spring quarters of 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024


    This lecture covers the fundamentals of the ecology, behavior and evolution of non-human primates, and how to study these in the wild. The topics encompassed include the human perception of primates, primate life history, feeding ecology, socioecology, concepts of group living and social behavior, communication, endocrinology, mating systems and kin selection. Moreover the course will focus on great apes, their societies, culture and cognition.

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    ANTH 107B

    Stable Isotope Ecology

    spring quarters of 2018, 2019, 2021, summer session 2019, winter 2023, coming up in winter 2025

    This combination of lectures and now also hands-on lab experiences (sample collection, sample prep, collagen extraction) provides students with a comprehensive overview of stable isotope research in fossil hominoids, prehistoric human populations and non-human primates. We discover the wide application of isotopic research in biological anthropology, bioarcheology, primatology, forensics and wildlife ecology.

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    ANTH 106A-C

    Chimpanzee Behavior & Culture


    This course on chimpanzee behavioral diversity will provide students with in depth understanding of the study of chimpanzee behavior from direct observations and camera trap footage. Students gain hands-on experience with the deployment and maintenance of our own trail cameras in the UCSC upper camps forest. Using free behavioral coding software (BORIS), we will also develop ethograms and analyze hundreds of videos of wild chimpanzees from Tanzania and assess their behavior.

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    ANTH Independent Study

    Chimpanzee Video Coding Team




    In this team project of up to 12 undergraduate students we code camera trap video footage from the Issa Valley in Tanzania, as savanna chimpanzee field site we are collaborating with via GMERC. Our task is to go through the video material, identify animal species and their behaviors, and entering the information into excel. We intensively discuss the identification of age, sex and individuals in chimpanzees. We meet at least once per week and discuss our progress and problems, and share our video highlights with each other. Actively participating student can obtain credits for 2-5 units (independent study).

    It’s all in your head. Credit: Tumblr via Pia Hollund

    ANTH 103

    Forensic Anthropology & Bioarchaeology

    spring 2017


    This hands-on lab class introduces students to the classic bioanthropological methods to determine age, sex, ancestry, body stature and health in human skeletal remains, such as modern forensic cases or archaeologically recovered material.


    ANTH 294

    Advanced Readings in Biological Anthropology



    This class is a small discussion round of PIs, grad students and postdocs that focuses on key research articles in our discipline. Advanced readings are novel or seminal journal articles suggested by the instructor or the participating graduate students. These papers will be relevant to biological anthropology in general, archaeological sciences or human evolution and we will particularly focus on articles employing isotope biogeochemistry and ancient DNA analytics. We will read, summarize and critically discuss research articles and rotate with the responsibilities of presenting the key findings of each article.

  • NEWS

    What's happening in the PEMA lab?

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    Elyse rocked presenting her research at the Building Belonging Fellowship Showcase - we are very proud!


    Invited talk at the UC Berkeley Archelogical Reserch Facility

    April 10th 2024 - zoom option available

    picture by Alex Piel

    Smithsonian Magazin article features our work !

    Check out the January/February 2024 issue article "A New Project Uses Isotopes to Pinpoint the Birthplaces of the Enslaved"

    picture by Seth Phillips

    Frontiers Sceince News on Phillips et al. 2023: "Fishing chimpanzees found to enjoy termites as a seasonal treat"

    Wang et al. 2023

    Angola Sr isoscape published, we hope it will make an impact!

    fun little clip about undergrad experiences in th PEMA lab

    featuring our new lab and facilities manager Kayla


    picture by Ngogo Chimpanzee Project

    Scholarship honoring Seb

    Sebastían Ramírez Amaya was tragically killed in 2022 while conducting fieldwork on chimpanzees in Uganda for his Ph.D. dissertation. To honor Sebastían, his friends and family have created a scholarship to support Masters and Ph.D. students from developing countries who conduct research and conservation projects on wild primates. This annual award will be administered by the International Primatological Society. You can contribute by donating


    through Paypal to sebscholarshipfund@gmail.com

    January 2023

    picture by Payton Sime

    Successful field season and faunal sampling at Issa Valley, Tanzania, with the folks from GMERC! with wonderful moments with local field staff, international researchers, the chimps, red-tailed monkeys and yellow baboons.

    September 2022

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    We mourn the tragic loss of our beloved friend and ASU colleague Sebastian, who was just wrapping up his one year field work at the Ngogo chimpanzee field site in Uganda. Rest in peace, Seb, you will never be forgotten!

    May 2022

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    Seth wrote a blog entry for GMERC on his latest field trip to Issa Valley, Tanzania to study termite activity patterns

    October 2021

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    our labs former undergraduate student Cielo De La Rosa 

    receives 2020-2021 Dean's Undergraduate Research Award for her senior thesis on Investigations on chimpanzee (Pan troglodytes schweinfurthii) termite-fishing cognition: Issa, western Tanzania. Her project was selected among the top 3 of all applications across the division. Congratulations Cielo for this recognition!

    picture by Paul Amblard-Rambert

    Our new isotope study on mandrills (Mandrillus sphinx) from Gabon made it on the cover of AJP! Find out more about the project at: http://www.projetmandrillus.com/

    November 2020

    picture by Gaelle Bocksberger

    UCSC NEWS - donation allows PEMA lab to build a strontium isotope map of equatorial Africa

    February 2020

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    Vicky was honored to join a special dinner with Jane Goodall, hosted by the Walt Disney Family in October 2019

    November 2019

    picture by Vicky Oelze

    Chimpanzee video coding team 2019 (several folks missing on this pic). We are turning this independent study group into a lab class in Winter 2020

    December 2019

    picture by VO

    Stable Isotope Ecology (ANTH 107B) class 2019 in the "field"

    ​successful and fun field sampling tour with both grads and undergrads; we went and explored upper campus forest and found many interesting plants, animals and fungi, which we prepared for stable isotope analysis

    May 2019

    picture by Vicky Oelze

    fume hood - Lab safety first!

    Dec 19th 2018: Good to know that a human dummy is good to use my brand new fume hood without inhaling toxic gases. Hope this level of safety also applies to real humans made of flesh & blood. Lab safety first!

    Seth in the field 2017/2018

    video by the GMERC team

    Field work is what you make of it!

    picture by Alex Piel

    UCSC News - "Tough life in the savanna"

  • former members of the PEMA lab and field assistants

    Picture by Vicky Oelze

    Dr. Xueye Wng

    postdoctoral researcher


    (now professor at Sichuan University, China)

    Picture by Vicky Oelze

    Dr. Gaëlle Bocksberger

    assistant researcher


    (now a the Senkenberg Musuem, Frankfurt, Germany)

    Picture by Vicky Oelze

    Tony Estrella

    undergraduate student (2021-2022)

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    Payton Sime

    field assistant (2021-2022)

    Issa Valley, Tanzania

    lab assistant (2019-2021)

    Chimp Video Coding Team

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    Julie Elliot

    lab assistant (2020-2021)

    Chimp Video Coding Team

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                Brennan Popovic

    undergraduate student

    Picture by Vicky Oelze

    Brynn Lowry

    lab assistant (2020-2021)

    Picture by Vicky Oelze

    Eden Washburn, PhD

    graduate student


    Picture by Vicky Oelze

    Cielo De La Rosa

    undergraduate student


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    Isabella O'Neal

    lab assistant/ intern


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    Kelsea Ranks

    undergraduate student


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    Gabriel Granado

    Koret Fellowship


    Picture by Vicky Oelze

    Victoria Collins

    lab assistant


    picture by Vicky Oelze

    James Luce

    tree climber, field assistant (2017)

    Taï National Park

    Picture by Vicky Oelze

    Florent Gnimion

    field assistant (2017)

    Taï National Park

    picture by Vicky Oelze

    Rumen Fernandez Martin

    field assistant, tree climbing assistant (2016)

    Taï National Park

    Picture by Vicky Oelze

    Dr. Simone Ban

    field assistant (2015)

    Taï National Park