1. Tools to tipple: ethanol ingestion by wild chimpanzees using leaf-sponges.

    Royal Society Open Science 2(6):150150 (2015) PMID 26543588 PMCID PMC4632552

    African apes and humans share a genetic mutation that enables them to effectively metabolize ethanol. However, voluntary ethanol consumption in this evolutionary radiation is documented only in modern humans. Here, we report evidence of the long-term and recurrent ingestion of ethanol from the r...
  2. Apes in the Anthropocene: flexibility and survival.

    Trends in Ecology & Evolution 30(4):215 (2015) PMID 25766059

    We are in a new epoch, the Anthropocene, and research into our closest living relatives, the great apes, must keep pace with the rate that our species is driving change. While a goal of many studies is to understand how great apes behave in natural contexts, the impact of human activities must i...
  3. Snakes as hazards: modelling risk by chasing chimpanzees.

    Primates 56(2):107 (2015) PMID 25600837

    Snakes are presumed to be hazards to primates, including humans, by the snake detection hypothesis (Isbell in J Hum Evol 51:1-35, 2006; Isbell, The fruit, the tree, and the serpent. Why we see so well, 2009). Quantitative, systematic data to test this idea are lacking for the behavioural ecology...
  4. Chimpanzees prey on army ants at Seringbara, Nimba Mountains, Guinea: predation patterns and tool use characteristics.

    American Journal of Primatology 77(3):319 (2015) PMID 25315798

    Chimpanzees are renowned for their use of foraging tools in harvesting social insects and some populations use tools to prey on aggressive army ants (Dorylus spp.). Tool use in army ant predation varies across chimpanzee study sites with differences in tool length, harvesting technique, and army...
  5. Grips and hand movements of chimpanzees during feeding in Mahale Mountains National Park, Tanzania.

    American Journal of Physical Anthropology 156(3):317 (2015) PMID 25363236

    It has long been assumed that stone tool making was a major factor in the evolution of derived hominin hand morphology. However, stresses on the hand associated with food retrieval and processing also have been recognized as relevant early hominin behaviors that should be investigated. To this e...
  6. Chimpanzees (Pan troglodytes verus) and their mammalian sympatriates: Mt. Assirik, Niokolo-Koba National Park, Senegal.

    Primates 55(4):525 (2014) PMID 24990446

    In intact, mosaic ecosystems, chimpanzees are sympatric with a wide range of other mammals, which may be predators, prey, or competitors. We delve beyond the nominal data of species lists to interval-level data on 35 medium-bodied and large-bodied mammals encountered at a hot, dry, and open fiel...
  7. Macroscopic inspection of ape feces: what's in a quantification method?

    American Journal of Primatology 76(6):539 (2014) PMID 24482001

    Macroscopic inspection of feces has been used to investigate primate diet. The limitations of this method to identify food-items to species level have long been recognized, but ascertaining aspects of diet (e.g., folivory) are achievable by quantifying food-items in feces. Quantification methods...
  8. Primates, insects and insect resources.

    Journal of Human Evolution 71:1 (2014) PMID 24703185

    There is a long-standing interest among paleoanthropologists in the potential significance of meat-eating by modern humans and extinct hominins. The potential importance of other forms of faunivory, including consumption of insects, have until recently received comparatively little att...
  9. Selective insectivory at Toro-Semliki, Uganda: comparative analyses suggest no 'savanna' chimpanzee pattern.

    Journal of Human Evolution 71:20 (2014) PMID 24792877

    Chimpanzee (Pan troglodytes) insectivory across Africa is ubiquitous. Insects provide a significant nutritional payoff and may be important for chimpanzees in dry, open habitats with narrow diets. We tested this hypothesis at Semliki, Uganda, a long-term dry study site. We evaluated prospects fo...
  10. The 'other faunivory' revisited: Insectivory in human and non-human primates and the evolution of human diet.

    Journal of Human Evolution 71:4 (2014) PMID 24560030

    The role of invertebrates in the evolution of human diet has been under-studied by comparison with vertebrates and plants. This persists despite substantial knowledge of the importance of the 'other faunivory', especially insect-eating, in the daily lives of non-human primates and traditional hu...
  11. Handedness is more than laterality: lessons from chimpanzees.

    Annals of the Lyceum of Natural History of New ... 1288:1 (2013) PMID 23601007

    Is human handedness unique? That is, do our nearest living relations, chimpanzee and bonobo (Pan spp.) show species-wide handedness, as is seen in living Homo sapiens? The answer may depend on definition: Handedness (congruence across subjects and across tasks) should be distinguished from hand ...
  12. Introduction to the evolution of human handedness.

    Annals of the Lyceum of Natural History of New ... 1288:v (2013) PMID 23742685

  13. Ranging behavior of Mahale chimpanzees: a 16 year study.

    Primates 54(2):171 (2013) PMID 23239417

    We have analyzed the ranging patterns of the Mimikire group (M group) of chimpanzees in the Mahale Mountains National Park, Tanzania. During 16 years, the chimpanzees moved over a total area of 25.2 or 27.4 km(2), as estimated by the grid-cell or minimum convex polygon (MCP) methods, respectivel...
  14. Community composition, correlations among taxa, prevalence, and richness in gastrointestinal parasites of baboons in Senegal, West Africa.

    Primates 54(2):183 (2013) PMID 23271438

    Studies of gastrointestinal parasite prevalence in Papio have either focused on a single troop or compared prevalence among troops that share migrants but differ in degree of human contact. Little is known about the extent of variation in prevalence where obvious factors that may drive prevalenc...
  15. The influence of ecology on chimpanzee (Pan troglodytes) cultural behavior: a case study of five Ugandan chimpanzee communities.

    Journal of Comparative Psychology (Abstracts) 126(4):446 (2012) PMID 22746159

    The influence of ecology on the development of behavioral traditions in animals is controversial, particularly for chimpanzees (Pan troglodytes), for which it is difficult to rule out environmental influences as a cause of widely observed community-specific behavioral differences. Here, we inves...
  16. Terrestrial nest-building by wild chimpanzees (Pan troglodytes): implications for the tree-to-ground sleep transition in early hominins.

    American Journal of Physical Anthropology 148(3):351 (2012) PMID 22460549

    Nest-building is a great ape universal and arboreal nesting in chimpanzees and bonobos suggests that the common ancestor of Pan and Homo also nested in trees. It has been proposed that arboreal nest-building remained the prevailing pattern until Homo erectus, a fully terrestrial biped, emerged. ...
  17. Chimpanzee carrying behaviour and the origins of human bipedality.

    Current Biology 22(6):R180 (2012) PMID 22440797

    Why did our earliest hominin ancestors begin to walk bipedally as their main form of terrestrial travel? The lack of sufficient fossils and differing interpretations of existing ones leave unresolved the debate about what constitutes the earliest evidence of habitual bipedality. Compel...
  18. Correlations between genetic and behavioural dissimilarities in wild chimpanzees (Pan troglodytes) do not undermine the case for culture.

    Proceedings of the Royal Society B: Biological ... 278(1715):2091 (2011) PMID 21490014 PMCID PMC3107635

  19. "An ape's view of the Oldowan" revisited.

    Evolutionary Anthropology 20(5):181 (2011) PMID 22034236

    In 1989, Wynn and McGrew published an explicit comparison between Oldowan technology and what was then known of chimpanzee technology. They compared the range and variety of tools, adaptive role of tools, carrying distances, spatial cognition, manufacturing procedures, and modes of learning. The...
  20. Are behavioral differences among wild chimpanzee communities genetic or cultural? An assessment using tool-use data and phylogenetic methods.

    American Journal of Physical Anthropology 142(3):461 (2010) PMID 20091837

    Over the last 30 years it has become increasingly apparent that there are many behavioral differences among wild communities of Pan troglodytes. Some researchers argue these differences are a consequence of the behaviors being socially learned, and thus may be considered cultural. Others contend...