No description available.

Serious primate field work, as distinct from the incidental and often anecdotal observations of early travellers, began with Carpenter's pioneering investigations of howler monkeys, red spider monkeys, and gibbons in the forests of Central America and the Far Fast (Carpenter 1934,1935,1940). The subject did not develop further until the early 1950's, with the establishment of long term studies on the Japanese macaque (e. g. Itani 1954, and many subsequent papers) and the work of Washburn, Hall and DeVore on savanna baboons in Africa (summarised in Hall and DeVore 1965, DeVore and Hall 1963). The last decade has seen a great expansion of interest in primate field studies, but research has not been spread evenly throughout the order. Most of the attention has been focused on savanna and open country animals rather than on the more numerous forest species. Some taxa such as the baboon-macaque group and the apes have been investigated fairly thoroughly, while others have been largely neglected, The reasons for the initial concentration of research on terrestrial species are clear. Open country animals are far easier to study than those living in dense vegetation. Once their confidence has been gained they can be followed throughout the day and long periods of concentrated observation are possible. Favourable conditions of observation permit the recognition of individual animals and hence detailed investigation of the relations between members of a troop. In contrast forest primates are difficult even to see, and even more difficult to follow. The return on time, energy, and money expended is correspondingly loner. In addition, much of the earlier work on primates in the 1950's was carried out by people whose prime interest was in the making of inferences to the social evolution of man. It was thought that animals living in a habitat supposedly comparable to that of early man would provide the greatest insight into the problems faced by our simian forbears. Under the circumstances, concentration of research on open country primates was a perfectly reasonable strategy. It has, however, had certain unfortunate consequences. In the early stages of the development of primatology the great diversity of social organisation to be found within the order was not suspected. For instance in 1961 Washburn and DeVore wrote of baboons: 'Although monkeys and apes certainly differ in their behaviour from one species to the next, we believe that the main points ... Mould not be greatly changed by substituting other nonhuman primate species for baboons'. (Washburn and DeVore 1961).

No description available.

Oreopithecus is an enigmatic primate from the Miocene of Italy. It has been the subject of more than a century of controversial research and debate. Most recently, the claim that Oreopithecus exhibited a substantial degree of bipedal behaviour has permeated the literature. Specifically, the pedal anatomy of Oreopithecus has been suggested to be unique among the hominoids and this has been advanced as evidence for bipedal adaptations in this taxon. The possibility that Oreopithecus was a bipedal ape is examined using geometric morphometric techniques to assess the shape of Oreopithecus pedal remains in comparison to other well-known species, and functional interpretations are drawn from these results. This study has examined the medial column of the pedal skeleton of five extant primate taxa, as well as that of Oreopithecus, Homo habilis, and Nacholapithecus. The possible function of the foot is considered in the context of published information regarding the rest of the postcranial skeleton of Oreopithecus and the known positional behaviour of the extant species used in the study. It is found that Oreopithecus closely resembles the African ape condition in the shape of its pedal skeleton, though there are subtle differences; however, none of the differences found in the pedal skeleton of Oreopithecus offer support to the contention that the foot was especially well-adapted to bipedal behaviour. The morphology of the medial cuneiform suggests that the degree of abduction of the hallux was comparable to that observed in Pan. Similarly, the morphology of the navicular, and the lateral and intermediate cuneiforms, indicate that the orientations of the articulations of the midfoot had a configuration that was more or less the same as that observed for extant African apes, particularly Pan. It is therefore concluded that Oreopithecus was probably not habitually bipedal. But the results presented here do not in and of themselves preclude bipedalism from its locomotory repertoire, as bipedal behaviour is exhibited among the extant apes to which it is similar. However, the finding that the foot of Oreopithecus was significantly smaller than it is in any extant ape casts doubt on the likelihood of any significant level of bipedalism and may indicate that Oreopithecus was adapted to a forelimb dominated locomotory strategy.

No description available.

No description available.

The thesis presented herein utilizes a variety of methods to address the biomechanical function of vertebrate hind limb bones in both modern and fossil species. In an innovative application of beam theory, the maximum force a long bone is capable of withstanding before yield is calculated under a variety of simplified loading conditions for a phylogenetically diverse sample of modern birds and mammals. In doing so, new insights are gained into the combined role of limb bone geometry and load vector in achieving mass-invariant safety factors under static loading. In particular, the avian femur is found to scale with sufficient allometry such that no postural modification is required to maintain constant safety factors across several orders of magnitude in body mass. In a methodological study, two techniques for estimating stress (simple beam theory and finite element analysis, FEA) are compared across a sample of morphologically diverse long bones. The extent to which stress estimates derived from the two modelling techniques diverge is found to correlate to aspects of the underlying bone morphology such as shaft curvature and cross-sectional asymmetry, and important recommendations are made regarding the appropriate application of both methods to skeletal material. A novel ’convex hull’ volumetric mass prediction technique for fossil birds is applied to two species of extinct moa (Dinornithiformes) from New Zealand. The resulting mass estimates are incorporated into a FEA study of the femora and tibiotarsi of modern ratites and moa. The ’stout southern’ moa (Pachyornis australis) is confirmed as possessing extremely robust limbs, whilst the ’terrible robust’ moa (Dinornis robustus) is found to possess equally, if not less, robust limb bones than those of modern ratites. The results are subsequently interpreted in the context of moa habitat range and shared ancestry. Finally the convex hull mass estimation technique is extended to modern primates, and the scaling of body mass with convex hull volume is compared across birds, primates and non-primate mammals. The allometric scaling of convex hull volume in birds and primates is considered in light of interspecific variation in muscle volume, body fat and integumentary structures, and is particularly relevant to those reconstructing the soft-tissue architecture of fossil species.

Short-term studies were made of the behaviour of tantalus monkeys in three habitats in order to describe any variation found and to investigate the functional relationship between that variation and the environment. The monkeys were studied in arid sahelian (thorn) savannah, broad-leaved guinea savannah and a mixed area of secondary forest and farmland. The three study sites are described in detail, and included in the descriptions are the results of brief surveys of the vegetation. The farmed forest was significantly vegetally denser than either of the savannah sites, providing more cover for the monkeys. The forest and the guinea-savannah were equally diverse in numbers of plant species but the sahel was poorer in this respect. The two savannah sites were more markedly seasonal in vegetal production than was the farmed forest. Feeding could not be studied quantitatively in the forest but in both savannah habitats the monkeys spent approximately one third of their total time and one third of their feeding time on the ground. Feeding techniques were typical for the species as described by other investigators and reflected a lack of dietary specialization. Meat and invertebrates were eaten as well as vegetable matter, and the proportions of different foodparts in the diet varied greatly both from month to month within each habitat and between habitats. Some social synchrony of feeding independent of the time of day at which the monkeys fed was observed at both savannah sites, but the diurnal cycles of feeding showed great daily variations. In the savannah areas, ranging patterns appeared to be determined by a combination of the distribution of food and water supplies and the desiccating effects of solar radiation. In the farmed forest, these constraints were eased and ranging patterns were more irregular. Population density, territoriality and typical group size (but not adult sex-ratio) varied greatly between habitats. The densest populations and largest groups were found in the sahel. Densities varied from 18 to 149 monkeys per km2, but although the highest density was associated with the largest groups the reverse (small groups with low density) did not occur. It is argued that population density may be limited by predation (by man) in the forest, by food in the guinea savannah and by intra-specific aggression in the sahel. Where territorial defence was observed, it was adaptive in relation to the hypothesised limiting factor on the population and was associated with relatively small social groups. The tantalus monkey is an historical newcomer to the farmed forest and the adaptations that it has made are discussed in detail. A summary of the main points of difference between the three study populations is given in an appendix.

Primates have evolved a wide range of locomotor behaviours to enable them to negotiate a three dimensional arboreal environment. Included in the primates are the lemurs, which have gained a reputation as specialist leapers with the sifaka (P. verreauxi) known for incredible saltatory displays. It is therefore necessary to have knowledge of this animals locomotor repetoire, substrate use, ranging and activity patterns in order to gain a greater understanding of sifaka ecology. The sifaka also inhabits a dry deciduous forest located in south western Madagascar which is characterized by a long dry season and short rainy season. This thesis begins with an investigation into the locomotion of P. verreauxi within Kirindy Mitea National Park. It was shown that leaping made up the largest proportion of the sifakas’ locomotor repetoire and that vertical supports were the most utilized, supporting the idea that sifakas are vertical clingers and leapers. Seasonal changes in behaviour were also displayed with levels of traveling behaviour increasing and resting behaviour decreasing during the short rainy season. These findings added weight to the growing body of evidence that lemurs conserve energy during periods of food scarcity in order to survive during the long dry season. These results were further supported by a ranging study, which used hand held GPS devices to measure home ranges and daily path lengths. It was discovered that the sifakas’ daily path lengths are much lower than that of both Old and New World monkeys. These path lengths also vary seasonally with decreased daily ranging during the dry season. A newer method of data collection was also investigated with the use of accelerometer data loggers being used in an attempt to monitor locomotion remotely. Although a captive study displayed that different locomotor modes can be distinguished from acceleration data, a field experiment using a very similar methodology failed to yield any useable data. The results suggest that P. verreauxi adapts its locomotor behaviour seasonally in order to cope with extended periods of food scarcity. helping add weight to the idea made by previous researchers that lemurs living in highly seasonal environments are adapted for conserving energy to deal with a harsh environment.

This thesis aims to assess if biting mechanics drives craniofacial morphology in recent hominins. To that end, a virtual functional morphology toolkit, that includes Finite Element Analysis (FEA) and Geometric Morphometrics (GM), is used to simulate biting, measure bite force and quantify deformations arising due to simulated biting in Homo sapiens and its proposed ancestral species, Homo heidelbergensis. Moreover, the mechanical significance of the frontal sinus and of the brow-ridge is also assessed in Kabwe 1 (a Homo heidelbergensis specimen). The frontal sinus is examined by comparing the mechanical performance in three FE models with varying sinus morphology. A similar approach is applied to the brow-ridge study. This approach relies on the assumption that FEA approximates reality. Thus, a validation study compares the deformations experienced by a real cranium under experimental loading with those experienced by an FE model under equivalent virtual loading to verify this assumption. A sensitivity analysis examines how simplifications in segmentation impact on FEA results. Lastly, the virtual reconstruction of Kabwe 1 is described. Results show that prediction of absolute strain magnitudes is not precise, but the distribution of regions of larger and smaller (i.e. pattern of) deformations experienced by the real cranium is reasonably approximated by FEA, despite discrepancies in the alveolus. Simplification of segmentation stiffens the model but has no impact on the pattern of deformations, with the exception of the alveolus. Comparison of the biting performance of Kabwe 1 and H. sapiens suggests that morphological differences between the two species are likely not driven by selection of the masticatory system. Frontal sinus morphogenesis and morphology are possibly impacted by biting mechanics in the sense that very low strains are experienced by this region. Because bone adapts to strains, the frontal sinus is possibly impacted by this mechanism. Lastly, biting mechanics has limited impact on brow-ridge morphology and does not explain fully the enormous brow-ridge of Kabwe 1. Hence, other explanations are necessary to explain this prominent feature.