Although several factors are likely to affect chimpanzee hunting decisions and meat sharing, results indicate that primary causes will not be found through invoking simple energetic or reproductive considerations.
The human–chimpanzee split is dated to at least 7–8 million years and the population split between Neanderthals and modern humans to 400,000–800,000 y ago, which suggests that molecular divergence dates may not be in conflict with the attribution of 6- to 7-million-y-old fossils to the human lineage and 400,,000-Y-old bones to the Neanderthal lineage.
The first quantitative support for the argument that variation in canopy structure influences decisions to hunt red colobus is provided, and implies that the chimpanzees hunt most when they can easily meet energy needs from other sources.
It is argued that defendability depends on the ability of an animal to monitor the boundaries of its range in order to detect potential intruders and introduces an index of defendability (D) which is the ratio of observed daily path length to an area equal to the diameter of a circle with areaequal to home range area of the animal.
In The Chimpanzees of the Budongo Forest, Reynolds reviews the results of 15 yr of behavioral research on chimpanzees and the efforts that he and others have made to protect them and it is curious and disappointing that Reynolds does not provide any comparative data to support the hypothesis that Budongo is an exceptional site in terms of fruit availability.
It is shown that male chimpanzees clearly prefer to affiliate and cooperate with their maternal brothers in several behavioral contexts, adding to a growing body of research that indicates that animals cooperate with each other to obtain both direct and indirect fitness benefits and that complex cooperation can occur between kin and nonkin alike.
The chimpanzees of the Mahale Mountains National Park, Tanzania, have been studied for more than 34 yr on the basis of individual identification and standardized attendance records to derive demographic data on disease, death, and female transfer.
Results from field research conducted in the Kibale National Park, Uganda are focused on, giving special emphasis to five areas: social organization, genetics and behavior, hunting and meat-eating, inter-group relationships, and behavioral endocrinology.
The results show that, as in males, kinship plays a limited role in structuring the intrasexual social relationships of female chimpanzees, and it is demonstrated that party association is as good a predictor of spatial proximity and grooming in females as it is in males.