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Since no previous unifying theoretical framework existed for viewing the different instances of chimpanzee predatory aggression (i.e., predatory behavior, cannibalism, infanticide, and warfare), the author developed a model for predatory aggression which differentiated the proximate and ultimate causes of predatory aggression, showed how these proximate and ultimate causes are correlated, showed how the ultimate function of any instance of predatory aggression is the solution of an ecological problem (thus contributing to the gene copying success of an individual and his kin), and showed how predatory aggression is likely to appear when any of a variety of combinations of proximal environmental factors causes the benefits of predatory aggression to exceed its costs.The model also helped suggest how developing inter-community and intra-community selection pressures initially made it advantageous for predatory aggression to be used on conspecifics, and how multiple selection pressures brought about the merging of intra-specific and inter-specific aggressive components in chimpanzee killing behavior.Essential to the creation of this model was a theoretical discussion of killing behavior, a survey of chimpanzee behavior and social structure, a survey of the incidence of chimpanzee killing behavior, and a summary of the various hypotheses for the cause and functions of predatory aggression.The author sees this model as an advance over previous explanations of chimpanzees predatory aggression because the model explains the ultimate as well as proximate causes of predatory aggression, it shows how the ultimate function of predatory aggression is to solve ecological problems and contribute to the gene-copying success of an individual and his kin, and it indicates how predatory aggression can link with other types of aggressive behavior patterns depending upon the immediate conditions of the environment.The importance of the preceding study lies in its ability to provide a model for the evolution of conspecific killing in protohominids.

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This thesis compares the tool-using behaviors and environments of nine chimpanzee study sites. In addition, tool-use in other animals is discussed, as is the social behavior of chimpanzees and the different contributions of wild and laboratory studies. Research centers on two primary questions:  Do chimpanzee study sites differ significantly in the types of tool-using behaviors they employ?  Is the amount of tool-using behaviors related to annual variability in rainfall or the overall wetness of a site? No significant differences exist between the different communities being studied. A significant correlation was found between diversity of tool-using behaviors and perhumidity index, a measure of overall wetness of a particular area. Finally, no correlations were found between diversity of tool-using behaviors and annual variability and rainfall. This analysis casts further doubt on the hypothesis that hominin technology evolved as a response to living in dryer, more open environments. / Tool-use and evolution -- Chimpanzee behavior -- Wild vs. captive studies -- Tool-use by chimpanzees -- Environment, study sites and methods -- Results / Department of Anthropology

Includes bibliographical references (leaves 873-896). / xxxvi, 896 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Reports on 2 experiments which investigated exploratory & other behaviour in the laboratory rat during fixed-interval, variable-interval, variable-ration and differential reinforcement of low rates schedules of reinforcement (& subsequent extinction.) A third experiment investigated exploratory & other behaviours in an open-field Skinner box during a fixed-interval schedule, with a concurrently available water source. The final experiments were conducted on a qualitative analysis basis at Adelaide Zoo. A number of novel objects were presented to a group of six chimpanzees, and a different set of objects presented to a pair of caracals, in an attempt to facilitate exploratory behaviour and reduce abberant behaviours. / Thesis (Ph.D.)--Adelaide University, Dept. of Psychology, 2001

This study examines the natural history of wild chimpanzees (Pan troglodytes verus) in Senegal, West Africa. This western form of chimpanzee is the least studied of the three geographical races. Ecological studies of chimpanzees have been neglected in favour of behavioural investigations. Those studies which have focussed on ecology have often been distorted by unnatural human intervention. Field studies of chimpanzees are reviewed in terms of their length, the extent of disturbance at the site, and the methods involved. The study area is described: its hot, arid climate and undisturbed state are emphasised. Methods were devised to gain knowledge of the chimpanzees' ecology without interfering with their behaviour or habitat. A detailed description of the types of vegetation is given, and their proportional distribution reveals that there is less forest and woodland at Mt. Assirik than at any other site where chimpanzees have been studied. Chimpanzees use the types of vegetation differentially and this shows seasonal variation. Forest is most used at the end of the dry season. At other times of the year, extensive use is made of woodland. Grassland is used during the wet season. Data from observations of chimpanzees and their nests is used to estimate the population size, range and density. The total number of chimpanzees at Mt. Assirik is estimated as about 25 to 30, density is reckoned as 0.1/km² and their home range as 250 to 300km². The chimpanzees appear to be healthy. Many features of social behaviour, described elsewhere, were confirmed for this subspecies. A high proportion of mixed parties was discovered. This is thought to be an adaptation to an area of open vegetation: its distribution of food, water, and the presence of large carnivores. The chimpanzees are omnivorous. Although mainly frugivorous, they also eat leaves, flowers, seeds, bark, honey, insects and meat. Two species of insect are eaten seasonally, and two types of tool are used to obtain termites and driver ants respectively. Chimpanzees appear to specialise in nocturnal prosimians as mammalian prey. Nests are examined in detail and found to be similar to those made elsewhere. Preferences, for certain species are demonstrated for the first time. Finally, the results of the study are compared with the cultural ecology of a human hunter-gatherer society, the !Kung San of Southern Africa. The comparison is used as a basis for speculation on the behaviour of the ancestral hominids.

Captive animals are frequently subject to imposed, uncontrollable stressors to which they respond through behavioural flexibility, or, failing which, exhibit pathology. Chimpanzees provide an intriguing model to examine how captive environments influence the responses of animals to stress. My study investigates the responses of a group of chimpanzees to imposed stressors of captivity at the Johannesburg Zoo, South Africa. My study comprised four components. Firstly, I examined the effects of spatial restriction on chimpanzee behaviour with regard to an enclosure enlargement, testing several existing models of coping with spatial crowding and another model, based on the coping hypothesis of abnormal behaviour. Behavioural observations of the chimpanzees in their indoor and outdoor exhibits before, during, immediately after and 10 weeks after the enclosure reconstruction revealed that the chimpanzees used tension-reduction and conflict-avoidance tactics as a means to cope with spatial crowding. Moreover, abnormal behaviour appears to provide an outlet for stress under crowding. Secondly, I assessed the long-term effects of past spatial environments on the space use and group spacing of the chimpanzees, five years after the enclosure change. Through behavioural observations and mapping the locations of individuals, I found that the chimpanzees exhibit space-use bias and limited group spacing, contingent on the dimensions of the old enclosure that were not explained by factors such as social or thermal conditions and zoo visitor effects. I propose that the spacing patterns may be due to spatial learned helplessness. Thirdly, I examined the effect of two social manipulations, mandated by zoo management, on the behaviour and socio-dynamics of the chimpanzees. The chimpanzees responded to social change through selective social interactions and non-social behavioural responses suggest that removing an individual was less stressful than the merging of two groups. Finally, I investigated the role of shade as a thermoregulatory resource for captive chimpanzees. Individuals used shade frequently despite observations taking place during the austral winter period, suggesting that shade is a valuable thermal resource for chimpanzees. In conclusion, the chimpanzees responded to most imposed stressors (spatial crowding, social change and thermal stress) through behavioural flexibility, implying successful coping, but failed to cope with previous spatial restrictions, resulting in limited space-use behaviour.

The behaviour of 48 chimpanzees (Pan troglodytes verus) was studied over 27 months in Liberia, West Africa. The chimpanzees were first studied while they were housed in groups in enclosures in a medical research institute, and then after their release onto a 9.7 ha offshore island. When the chimpanzees were observed in captivity, data on social behaviour were collected with the use of check sheets and ad libitum notes. Data were collected on aggression, social grooming, social play, sexual behaviour, and individual spacing. After release onto the island, data on both social and subsistence behaviour were collected with the use of ad libitum notes. Both changes in social behaviour and in the development of subsistence behaviour were observed following release of the chimpanzees onto the island. Rates of aggression decreased following release, whereas rates of social grooming increased. Rates of social play decreased overall, but this was due to a decrease in social play by adults. Stereotyped or abnormal behaviour shown by some subjects declined. Subsistence behaviours which were observed following release were foraging for naturally occurring foods (leaves, fruits, seeds, and nuts), ant-eating, and tool-use for nut-cracking. Some subjects were also seen building sleeping-nests in trees. The chimpanzees also split into subgroups (including consortships) which showed similar trends in size and composition to those observed in wild populations of chimpanzees. Some techniques found to be useful during the release process are discussed, and the study is compared to previous primate release projects.