Thesis (M.A.)--University of Wisconsin--Madison, 1969. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1981. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 121-126).

No description available.

Most of what we know of the socioecology and behaviour of gorillas comes from studies of mountain gorillas (Gorilla beringei beringei), despite their representing less than 1% of all gorillas in the wild. Western lowland gorillas (Gorilla gorilla gorilla) have received far less research effort, and difficulties in habituation have led previous studies to rely heavily on indirect trail evidence. This has prevented any in-depth comparison of social structure and behaviour between species. The discovery of swampy clearings frequented by western lowland gorillas in northern Congo has offered the first opportunity to obtain accurate demographic and behavioural data. This thesis reports on 6273 hours of observer presence at Mbeli Bai, which yielded 1681 hours of direct gorilla observation. Most data come from a population of 13 groups and 7 solitary silverbacks. Group size ranged from 2 to 16 (mean = 8.4, SD 4.3) which does not differ significantly from data published on most other populations. Female natal and secondary transfer were recorded, and male emigration from the natal group appeared universal (no multi-silverback groups were recorded). No evidence of sub-grouping or a fission-fusion grouping pattern was found. During intra-group interactions, no evidence was recorded of female philopatry, and silverbacks herded and intimidated females (especially new immigrants) to prevent emigration. Inter-unit interactions took place on only 42% of shared bai-use occasions, and levels of silverback agonism were much lower than in mountain gorillas, with peaceful mingling of groups recorded. Display behaviour was common, and two previously unrecorded agonistic displays (the splash display and the crest display) are described. No contact aggression between silverbacks was observed but evidence of wounding sustained in the forest suggests that the bai environment may inhibit such aggression. High visibility and the ease of silverback 'policing' are thought to create an unusually tolerant social dynamic, and as such, frequencies of certain social behaviours should probably be viewed as site-specific. The thesis offers the fullest account of western gorilla social structure and behaviour to date. Long-term monitoring of life history variables, if continued, will provide an unparalleled opportunity to understand the effects of habitat and food availability and more stochastic influences on western gorilla social structure, fitness, and survival.

Thesis (Ph. D.)--Kent State University, 1999. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--Kent State University, 1999. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.A.)--York University, 2007. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 40-49). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR38790

No description available.

With the increase in research on age-related decline in human cognitive capabilities has come an increased demand for a nonhuman cognitive aging model that controls for confounds in the human research, including education, socio-economic class, and language abilities. A nonhuman primate model of cognitive aging is particularly attractive given the similarities in physiology and behavior between nonhuman primates and humans. The rhesus macaque has proven to be a highly effective model of human aging, but apes, the closest genetic relatives to humans, are virtually unstudied. Only three studies have examined age-related changes in cognitive abilities in apes, and all three studies were conducted using tasks that have had relatively little success in revealing age-related performance decline in monkeys. Sixteen gorillas housed at Zoo Atlanta and Disneys Animal Kingdom underwent five experiments to determine the effects of age, sex, and previous research experience on performance. Testing occurred in a modified Wisconsin General Test Apparatus using the delayed response paradigm. When delay intervals were increased from zero to 90 seconds performance decreased across all subjects. However, there was no univariate effect of age, sex, or experience on performance. Similarly, when the number of potential choice sites was increased from two to four there was a decrease in performance, but again there was no univariate effect of age, sex, or experience. However, older subjects were more likely to have a response bias and choose a single site across all tasks, irrespective of where the reward was located. This effect was more pronounced in inexperienced subjects. As a result, age does not appear to affect performance accuracy in the delayed response task in gorillas, but there may be an effect on response rigidity. Given the shortcomings of the delayed response task in simple cognitive studies with nonhuman primates, further research on cognitive aging in gorillas should utilize a research naïve population and use an experimental protocol that is titrated based on individual responses. This will allow the delay interval to be gradually increased to a point where age-related differences may be apparent.

No description available.