Barriers to chimpanzee gene flow at the south-east edge of their distribution.

Populations on the edge of a species' distribution may represent an important source of adaptive diversity, yet these populations tend to be more fragmented and are more likely to be geographically isolated. Lack of genetic exchanges between such populations, due to barriers to animal movement, can not only compromise adaptive potential but also lead to the fixation of deleterious alleles. The south-eastern edge of chimpanzee distribution is particularly fragmented, and conflicting hypotheses have been proposed about population connectivity and viability.

Personality traits, rank attainment, and siring success throughout the lives of male chimpanzees of Gombe National Park.

Personality traits in many taxa correlate with fitness. Several models have been developed to try to explain how variation in these traits is maintained. One model proposes that variation persists because it is linked to trade-offs between current and future adaptive benefits.

The long lives of primates and the 'invariant rate of ageing' hypothesis.

Is it possible to slow the rate of ageing, or do biological constraints limit its plasticity? We test the 'invariant rate of ageing' hypothesis, which posits that the rate of ageing is relatively fixed within species, with a collection of 39 human and nonhuman primate datasets across seven genera. We first recapitulate, in nonhuman primates, the highly regular relationship between life expectancy and lifespan equality seen in humans. We next demonstrate that variation in the rate of ageing within genera is orders of magnitude smaller than variation in pre-adult and age-independent mortality.

Insights into the evolution of social systems and species from baboon studies.

Baboons, members of the genus comprise six closely related species distributed throughout sub-Saharan Africa and southwest Arabia. The species exhibit more ecological flexibility and a wider range of social systems than many other primates. This article summarizes our current knowledge of the natural history of baboons and highlights directions for future research.

CD4 receptor diversity in chimpanzees protects against SIV infection.

Human and simian immunodeficiency viruses (HIV/SIVs) use CD4 as the primary receptor to enter target cells. Here, we show that the chimpanzee CD4 is highly polymorphic, with nine coding variants present in wild populations, and that this diversity interferes with SIV envelope (Env)-CD4 interactions. Testing the replication fitness of SIVcpz strains in CD4 T cells from captive chimpanzees, we found that certain viruses were unable to infect cells from certain hosts.

Morphological Identification of Hair Recovered from Feces for Detection of Cannibalism in Eastern Chimpanzees.

Chimpanzees (Pan troglodytes) are primarily frugivorous but consume a variable amount of meat from a variety of organisms, including other chimpanzees. Cannibalism is rare, usually follows lethal aggression, and does not occur following natural deaths. While chimpanzee cannibalism has been documented at multiple sites, many instances of this behavior go unrecorded.

Allometry and Ecology of the Bilaterian Gut Microbiome.

Classical ecology provides principles for construction and function of biological communities, but to what extent these apply to the animal-associated microbiota is just beginning to be assessed. Here, we investigated the influence of several well-known ecological principles on animal-associated microbiota by characterizing gut microbial specimens from bilaterally symmetrical animals () ranging from flies to whales. A rigorously vetted sample set containing 265 specimens from 64 species was assembled.

Complete mitochondrial genome of an olive baboon () from Gombe National Park, Tanzania.

The olive baboon () is the most widely distributed baboon species. We report here on the complete mitochondrial genome of an olive baboon from the south-eastern edge of the species' range from Gombe National Park (NP), Tanzania. The genome (GenBank accession number MG787545) has a length of 16,490 bp and exhibits the typical structure of mammalian mitochondrial genomes.

Personality in the chimpanzees of Gombe National Park.

Researchers increasingly view animal personality traits as products of natural selection. We present data that describe the personalities of 128 eastern chimpanzees (Pan troglodytes schweinfurthii) currently living in or who lived their lives in the Kasekela and Mitumba communities of Gombe National Park, Tanzania. We obtained ratings on 24 items from an established, reliable, well-validated questionnaire used to study personality in captive chimpanzee populations.

Predation by female chimpanzees: Toward an understanding of sex differences in meat acquisition in the last common ancestor of Pan and Homo.

Among modern foraging societies, men hunt more than women, who mostly target relatively low-quality, reliable resources (i.e., plants).

Feeding habitat quality and behavioral trade-offs in chimpanzees: a case for species distribution models.

The distribution and abundance of food resources are among the most important factors that influence animal behavioral strategies. Yet, spatial variation in feeding habitat quality is often difficult to assess with traditional methods that rely on extrapolation from plot survey data or remote sensing. Here, we show that maximum entropy species distribution modeling can be used to successfully predict small-scale variation in the distribution of 24 important plant food species for chimpanzees at Gombe National Park, Tanzania.

Non-invasive quantification of immunoglobulin A in chimpanzees (Pan troglodytes schweinfurthii) at Gombe National Park, Tanzania.

Immunoglobulin A (IgA) is the primary antibody responsible for mucosal defense in mammals and has been used as a marker for chronic stress and immune status. Therefore, this antibody may provide a more reliable indicator of an individual's immunocompetence than is currently available through other methods. Immunoglobulin A has never before been quantified in a wild population of non-human primates using non-invasive sample collection techniques.

'Impact hunters' catalyse cooperative hunting in two wild chimpanzee communities.

Even when hunting in groups is mutually beneficial, it is unclear how communal hunts are initiated. If it is costly to be the only hunter, individuals should be reluctant to hunt unless others already are. We used 70 years of data from three communities to examine how male chimpanzees 'solve' this apparent collective action problem.

Maternal Behavior and Physiological Stress Levels in Wild Chimpanzees ().

Individual differences in maternal behavior toward, and investment in, offspring can have lasting consequences, particularly among primate taxa characterized by prolonged periods of development over which mothers can exert substantial influence. Given the role of the neuroendocrine system in the expression of behavior, researchers are increasingly interested in understanding the hormonal correlates of maternal behavior. Here, we examined the relationship between maternal behavior and physiological stress levels, as quantified by fecal glucocorticoid metabolite (FGM) concentrations, in lactating chimpanzees, , at Gombe National Park, Tanzania.

Lethal aggression in Pan is better explained by adaptive strategies than human impacts.

Observations of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) provide valuable comparative data for understanding the significance of conspecific killing. Two kinds of hypothesis have been proposed. Lethal violence is sometimes concluded to be the result of adaptive strategies, such that killers ultimately gain fitness benefits by increasing their access to resources such as food or mates.

Rank effects on social stress in lactating chimpanzees.

Given the deleterious consequences associated with chronic stress, individual differences in stress susceptibility can have important fitness implications. These differences may be explained in part by dominance status because high rank is typically associated with decreased aggression and improved nutrition. Here, we examined the relationship between dominance and social stress in lactating chimpanzees, , at Gombe National Park, Tanzania.

Anogenital swelling in pregnant chimpanzees of Gombe National Park.

Previous studies show that anogenital swelling patterns of pregnant chimpanzees in captivity are correlated with the female's age during pregnancy and are associated with changes in social behavior. The purpose of the present study was to investigate whether the anogenital swelling patterns of free-ranging pregnant chimpanzees resemble those reported for captive chimpanzees. We reviewed the records of 47 pregnancies experienced by 20 female chimpanzees living in Gombe National Park from 1975 to 1992.