Browsing by Subject "Chimpanzees"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    From birth to bones: skeletal evidence for health, disease, and injury in the Gombe chimpanzees.
    (2010-08) Kirchhoff, Claire Ann
    The Gombe skeletal collection is the largest assemblage of wild chimpanzee skeletons with known life histories. As such, it provides an unprecedented opportunity to explore the relationship between behavior and the skeleton. I examined skeletal markers of health and stress, and their relationship to age, sex, and dominance rank. Age was correlated with arthropathy incidence and pathology incidence, but the inclusion of chimpanzee infanticide victims resulted in a more complex relationship between age and trauma incidence. Sex was not correlated with trauma or pathology incidence, but the distribution of traumata differed between males and females. Neither age nor sex correlated with enamel hypoplasia severity. Dominance rank did not correlate with any of the skeletal markers of health or stress, but change in rank was a significant predictor in some cases. These results should be treated with caution because the number of chimpanzees whose ranked changed is very small. It may be possible to better assess the effects of change in rank on rates of skeletal trauma and pathology in the future.
  • Thumbnail Image
    Item
    Stable Isotope Ecology of Gombe National Park: A Modern Analogue for Fossil Hominins
    (2019-09) Nockerts, Rebecca
    Stable isotopes have revolutionized our understanding of the evolution of the human diet. A key early transition in hominin evolution appears to be the increased consumption of C4 grasses and sedges (and/or animals eating C4 plants) and an adaptation towards more open, seasonal environments. The earliest hominins, Ardipithecus ramidus and Australopithecus anamensis, appear to have had diets reliant on C3 foods, interpreted to be similar to the diets of modern chimpanzees. All later hominins after ~3.5 Mya were mixed C3/C4 feeders, though the extent of C4 consumption varied tremendously, both within and between species. Important limitations remain in using modern referential models to interpret this change in dietary ecology. These include the need for an improved understanding of diet to tissue isotope enrichment and studies of appropriate living populations, in comparable environments, with independently known feeding histories. In order to address those limitations, I conducted a comprehensive analysis of the stable isotope ecology of the chimpanzees (Pan troglodytes schweinfurthii) and baboons (Papio anubis) of Gombe National Park, Tanzania. Both chimpanzees and baboons have been invoked as species with ecological adaptations similar to those of fossil hominins. At Gombe these primates share overlapping ranges in a mixed forest/woodland/grassland habitat similar to those inferred for many hominin localities. I combined observational records of their diets and the isotopic composition of their foods to interpret the isotopic signatures of their hair, nails, bones, and teeth. I then compared these results to previously published isotope studies of other populations of Pan, Papio, and fossil hominins and papionins. I found that Gombe plant isotopes varied across plant growth form and plant part, as well as seasonally and across different habitat types. This variation was reflected, to varying degrees, by differences in the isotopic composition of chimpanzees compared to the baboons. Other aspects of the dietary ecology of the Gombe chimpanzees and baboons are reflected by their tissues, including breastfeeding, variable C4 consumption, and differences in meat and insect consumption. These results indicate that even the earliest known hominins consumed substantially more C4 food resources than any known chimpanzee population, and more than many forest-living baboon populations.