Chimpanzees (Pan troglodytes) make nests for resting and sleeping, which is unusual for anthropoid primates but common to all great apes. Arboreal nesting has been linked to predation pressure, but few studies have tested the adaptive nature of this behavior. We collected data at two chimpanzee study sites in southeastern Senegal that differed in predator presence to test the hypothesis that elevated sleeping platforms are adaptations for predator defense. At Assirik in the Parc National du Niokolo-Koba, chimpanzees face four species of large carnivore, whereas at Fongoli, outside national park boundaries, humans have exterminated almost all natural predators. We quantified the availability of vegetation at the two sites to test the alternative hypothesis that differences in nesting reflect differences in habitat structure. We also examined possible sex differences in nesting behavior, community demographic differences, seasonality and nest age differences as variables also potentially affecting nest characteristics and nesting behavior between the two sites. Chimpanzees at Fongoli nested at lower heights and farther apart than did chimpanzees at Assirik and sometimes made nests on the ground. The absence of predators outside of the national park may account for the differences in nest characteristics at the two sites, given the similarities in habitat structure between Fongoli and Assirik. However, Fongoli chimpanzees regularly build arboreal nests for sleeping, even under minimal predation pressure, and this requires explanation.

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Bonobos (Pan paniscus) consume a variety of vertebrates, although direct observations remain relatively rare compared to chimpanzees (Pan troglodytes). We report the first direct observations of meat eating and sharing among bonobos at Iyema, Lomako Forest, Democratic Republic of Congo. We collected meat consumption data ad libitum from June to November 2017 over 176.5 observation hours and conducted monthly censuses to measure the abundance of potential prey species. We observed 3 occasions of duiker consumption and found indirect evidence of meat consumption twice (n = 5). We identified the prey species as Weyn’s duiker (Cephalophus weynsi) in all 4 cases that we saw the carcass. This species was the most abundant duiker species at Iyema, but other potential prey species were also available. Meat sharing was observed or inferred during all 3 observations. However, the individual controlling the carcass frequently resisted sharing, and aggressive attempts to take the carcass were observed. This report contributes to a growing body of data suggesting that wild bonobos consume meat at higher rates than previously thought, female control of carcasses is frequent but not exclusive, and meat sharing in bonobos is primarily passive but not without aggression.