Thesis (M. S.)--Madras, 1942. / Includes index. Bibliography: p. [170]-176.

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Recent studies on the social life and vocal production, usage and comprehension of nonhuman primates have brought new insights into the evolutionary mechanisms of cognition and communication as well as the emergence of language. A key point in the current literature concerns the flexibility of vocal production. In contrast to humans, some birds and some cetaceans, vocal flexibility is thought to be very restricted in nonhuman primates, which creates a startling phylogenetic gap. At the same time, research has shown that a number of African forest guenons' alarm calls appear to have language-like properties. With the hypothesis that looking at the vocal repertoire more broadly, especially the social calls, was likely to reveal other complex communicative abilities, I studied in detail the social life and vocal behaviour of a guenon species, Diana monkeys. First, the comparison of its social system with the system of another closely related species, Campbell's monkeys, stressed in both species the reduced number of physical interactions, although females maintained preferential relationships that were not biased towards kin. Second, the study of Diana females' vocal repertoire is restricted but flexible. Females emit social calls with a combinatorial structure, the use of which is affected by external events. Third, focusing on a highly frequent and highly social call revealed flexibility in the identity advertisement (divergence – convergence) which accommodates to the context. Fourth, to explore the nature of nonhuman primates' comprehension skills, I performed playback experiments of De Brazza monkey social calls to three species of Old World monkeys; Campbell's monkeys, black-and-white colobus monkeys and red-capped mangabeys. Altogether, the three species were able to discriminate hetero-specific voices of individuals they knew from individuals they had never met. Overall, my results have revealed a considerable degree of flexibility in the vocal communication of nonhuman primates, a finding that is consistent with the hypothesis of a continuous evolutionary transition from animal vocal behaviour to human language.

The principle objective of this study was to describe and record all the gathering and processing skills of vervet monkeys for a variety of different foods. The study was conducted on two troops of vervet monkeys living in the Palmiet Valley, Natal, South Africa. There was sufficient data to analyze the processing of four foods of differing complexity; termites, leaf shoots, sugarcane and fruit. Milton (1988) proposed that the intellectual difficulties of finding and processing food led to the evolution of intelligence. In the only study of food processing skill, Byrne and Byrne (1993) showed that gorillas use a hierarchical organization perhaps reflecting imitation at the program-level. The question to be asked in this study was, would vervets also organize their processing into a few techniques for specific foods and would it then be possible to identify learning mechanisms used by the monkeys? The current literature suggests that monkeys use simple solutions to their foraging problems, there is no evidence for imitation of feeding skills in monkeys. At the most detailed level of analysis, grip types used in the processing of foods were described. Existing definitions in the literature were not adequate to explain the monkeys' hand use, and new definitions were added. High individual idiosyncrasy was a feature of grip usage across all four foods, although firm conclusions are not possible because of the known effects of sample size. Cluster analysis was considered the most appropriate method to look at individual variation in grip usage. There was an age effect for leaf shoots and sugarcane, with juveniles restricting their usage to the necessary core grips. The hand preferences for individuals across tasks gave no support for the theory of the evolution of laterality presented by MacNeilage et al. (1987). There was a low degree of individual preference for five out of six tasks, with only termite feeding showing a hand preference. There was some evidence for a right hand reaching, left hand manipulation preference, opposite to MacNeilage's prediction. There was an age effect in direction and strength for two tasks, adults having a stronger left hand preference in contrast to a weaker right hand preference in juveniles for leaf shoots and large fruit. Matrices of the transitional probabilities between two elements, were used to construct the common pathways of processing skill for each individual. Flow diagrams were then created to represent the minimal decision processes used by the monkeys. The diagrams were used to compare individuals' choice of pathways. Cluster analysis was used to analyze pathway choice in detail; none of a variety of independent variables could explain the high individual variation. Whether whole foods or just parts of foods were eaten did explain some of the variance for sugarcane and fruit. The most parsimonious explanation is that social enhancement resulting in trial and error learning best described individuals' acquisition of processing skill, although a number of other factors may explain the observed results.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, in fulfilment of the requirements for the higher degree of Doctor of Philosophy. July, 2016. / Fossil primates are some of the most well represented fauna in South Africa’s fossil Plio-Pleistocene cave sites. Sterkfontein preserves the largest number of fossil primates and a large portion of these are cercopithecoid remains. This research project provides a taxonomic analysis of the abundant fossil cercopithecoid post-cranial limb elements discovered at the site. One thousand five hundred fourteen identifiable fossil cercopithecoid postcrania from the Sterkfontein caves are analysed. From these, five genera are identified from morphologically diagnostic postcranial elements; these are Papio, Parapapio, Theropithecus, Cercopithecoides and Cercopithecus. Theropithecus is identified in Member 4, earlier than previously known. It is established that size, form and function are important factors in taxonomic studies. They play a major role in taxonomic examinations; however, they cannot be treated as disconnected facets of a taxonomic exercise. Each plays an essential role in taxonomic analyses. The study confirms that the Member 4 environment, which illustrates the turn from the Pliocene to the Pleistocene and the most mosaic of all the Plio-Pleistocene sites of the Cradle of Humankind World Heritage Site, samples the most faunal variability in the Sterkfontein Cave deposits. This research supports the hypothesis that carnivores were not the main accumulating agent for the cercopithecoid fossil remains within the caves. The carnivores, however, impacted the fossil cercopithecoid assemblage. Leopards and hyaenas are identified as some of the carnivores which accumulated the fossil cercopithecoids within the Sterkfontein caves. The research has opened a new scope for taxonomic analysis of isolated fossil cercopithecoid postcrania in the southern African fossil cave sites. / LG2017

Savannah baboons are amongst the most intensively studied taxa of primates, but our understanding of their foraging strategies and diet selection, and the relationship of these to social processes is still rudimentary. These issues were addressed in a 12-month field study of olive baboons (Papio anubis) on the Laikipia plateau in Kenya. Seasonal fluctuations in food availability were closely related to rainfall patterns, with the end of the dry season representing a significant energy bottleneck. The distribution of water and of sleeping sites were the predominant influences on home range use, but certain vegetation zones were occupied preferentially in seasons when food availability within them was high. The influence of rainfall on monthly variation in dietary composition generally mirrored inter-population variation. Phytochemical analysis revealed that simplistic dietary taxonomies can be misleading in the evaluation of diet quality. Food preferences were correlated with nutrient and secondary compound content. The differences between males and females in daily nutrient intakes were smaller than expected on the basis of the great difference in body size; this was partly attributable to the energetic costs of reproduction, and possibly also to greater energetic costs of thermoregulation and lower digestive efficiency in females. A strongly linear dominance hierarchy was found amongst the adult females. Dominance rank was positively correlated with food ingestion rates and daily intakes, but not with time spent feeding or with dietary quality or diversity. In a provisioned group, high-ranking females occupied central positions, while low-ranking females were more peripheral and were supplanted more frequently. In the naturally-foraging group, the intensity of competition was related to the pattern of food distribution, but not to food quality, and was greater in the dry season than in the wet season. The number of neighbours and rates of supplanting were correlated with rank, and evidence was presented that high-rankers monopolised arboreal feeding sites.

Thesis (Ph. D.)--University of Chicago, Department of Anthropology, December 2002. / Includes bibliographical references. Also available on the Internet.

This thesis investigated effects of manipulative experience on tool-using ability of tufted capuchins. Two groups of capuchins were tested on variations of a tool-using task, involving use of an object as a tool to dislodge a reward from a tube. The tasks were modelled after those developed by Visalberghi and Limongelli (1994) and Visalberghi and Trinca (1989). One group of monkeys was provided the opportunity to manipulate task materials without reward; the other group was not. Experiment 1 required subjects to push a rod through the tube. Experience with task materials improved capuchins' efficiency, evidenced by faster completion of trials. In Experiment 2, short pipes could be combined to create a tool of sufficient length. Due to procedural problems, results were inconclusive. Experiment 3 required subjects to manufacture the appropriate tool. Experience with task materials improved capuchins' performance, evidenced by faster completion of trials, less frequent performance of inefficient behaviours, and decrease in errors across trials. When capuchins' performance was compared with enculturated chimpanzees tested previously on the task (Visalberghi, Fragaszy, and Savage-Rumbaugh, 1995), experienced capuchins performed as efficiently after 15 trials as had chimpanzees originally. In Experiment 4, subjects had to dislodge the reward from a tube containing a trap. Because successful levels of performance were not reached, results were inconclusive. In Experiments 5 and 6, appreciation of object affordances was examined. The capuchins demonstrated an ability to distinguish between functional characteristics of objects. These results suggest previous claims regarding limitations of capuchin tool-use may have underestimated their abilities. Further, because object experience enhances tool-using ability, previous comparisons of capuchins with enculturated chimpanzees seem to have misrepresented the magnitude of difference in their abilities. However, future research comparing species with the same experiential backgrounds is necessary to elaborate on differences in cognitive processes underlying capuchin and chimpanzee tool-using behaviour.

It is hypothesised that young baboons are potentially vulnerable to the effects of seasonal stress. Data were collected on the behaviour of this age group during a 12 month field study of a troop of olive baboons (Papio anubis) on the Laikipia plateau, Kenya, using a hand-held computer and a new program written by the author. Long-term environmental records for this site were continued. At this site there is a seasonal pattern of rainfall with inter-annual variation. Measures of biomass indicate that there are seasonal fluctuations in baboon food availability. Patterns in the occurrence of one component of the baboon's diet, Acacia species, are presented. The varying behaviour of the troop as a whole is related to food availability. Differential use of the home range and observed sub-trooping behaviour are interpreted as adaptive strategies for living in a seasonal environment. Developmental change in the behaviour associated with the mother-offspring relationship is described. Patterns in the time spent in contact with and close proximity to the mother from this site are compared with those from other sites, and striking similarities are found. Many of the behavioural activities of infants and young juveniles, i.e. feeding, moving, types of exploring, visually attending, grooming, and receiving affiliative approaches, exhibit patterns of developmental change. Interactions between activities are examined in the context of the complete activity budget. The effect of seasonal stress on young baboons is examined by using a technique of curve fitting. Data are compared between periods of higher and lower food availability. Significantly more time is spent feeding and less time spent in social and attending activities in the 'worst' than the 'best' months. Young baboons vary their diets seasonally. There is evidence that older infants (weanlings) are more vulnerable to the impact of seasonal stress than either young infants or young juveniles.

This thesis investigates the nature of post-conflict behaviour and relationships among individuals in two captive groups of pigtail macaques, Macaca nemestrina, and one wild troop of olive baboons, Papio anubis. Data were collected during periods of seven and twelve months respectively. In both pigtail groups, conflicts were more frequently reconciled between opponents with strong affiliative ties. However, reconciliation was twice as common in the well-established group where individuals' social networks were more compact. It is argued that the more intense ties produced by restricted networks increased the likelihood of reconciliation. Reconciliation was demonstrated among wild olive baboons, occurring at a rate consistent with a relatively intolerant dominance style. Opponents who were close kin or of similar rank reconciled relatively frequently, but reconciliation rarely followed conflicts associated with food. Olive baboons did not 'console' each other, consistent with the hypothesis that consolation requires an ability to empathise with victim distress. Initiation of post-conflict attacks on third parties was not elevated in victims of aggression. Among the baboons, both victims and initiators of aggression exhibited elevated rates of post-conflict self-directed behaviour (a combined measure of scratching, autogrooming, body-shaking and yawning). Reconciliation reduced both SDB and the incidence of further aggression. However, reconciliation only reduced SDB among individuals involved in conflicts in which they had both received and delivered aggression. Female baboons showed significantly higher rates of SDB when their nearest neighbour (within 5 m) was a dominant conspecific than when he or she was a subordinate individual, supporting the hypothesis that SDB indexes stress in primates. This result suggests that SDB can be used to index relationship security in primates.