3. Electronic Theses and Dissertations (ETDs) - All submissions
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Item The skull and mandible of the South African baboon.(1975) Trevor-Jones, Trevor RubidgeThe skull and mandible of the baboon. This is a morphological study of the skulls and mandibles of 102 specimens from known localities in Southern Africa. A detailed reference book on the anatomy of the baboon is particularly important because of the increasing use of this animal in medical science. The skulls and mandibles of captive animals are referred to but are not included in the comparative study since animals in captivity are subject to dietetic disturbances and other factors not yet fully understood. The cranium of an adult male skull is described in all normae. Comparisons are made with the crania of seven adult male baboons from widely separated known localities. This study shows that two main craniofacial types, with intermediate types, occur among the crania of South African baboons. Type 1. crania have small maxillary ridges, shallow maxillary fossae, ventrally directed zygomatic bones, large ventral orbital apertures, well developed superciliary ridges, high temporal lines and sagittal crests. Type 11. crania have large flared maxillary ridges, deep maxillary fossae, ventrolateral ly directed zygomatic bones, small ventral orbital apertures, large supraorbital tori, low temporal lines and no sagittal crests. This apparent1y supports the specific and subspecific claims of some observers. However, a critical examination of the crania of six adult female baboons from the same troop at Bindura, Rhodesia, shows that similar craniofacial types occur among female baboons. It is possible to associate mandibular types with the craniofacial types in adult male baboons. This is not the case with female baboon mandibles.Item Biologging as a method to remotely detect orientation to solar radiation in black and blue wildebeest(2015-04-17) Botha, AristaAnimals can shift their orientation to solar radiation to adjust the amount of body surface area that is exposed to solar radiation, thereby manipulating the amount of radiant heat they absorb from their environment. This behaviour is especially important in animals that need to graze out in the open during the day, such as wild ungulates. All previous studies of orientation to solar radiation in animals have relied on visual observations. The problem with visual observations is that animal behaviour, including animal orientation, can be affected by human presence. Therefore I set out to develop a remote technique to detect and quantify orientation to solar radiation in wildebeest to eliminate the need of a human observer. I hypothesised that if an animal was orientated perpendicular to solar radiation, the side facing the sun would be hotter than the opposite side. In contrast, if the animal was orientated parallel to solar radiation I hypothesised that both sides will have a similar temperature. To test my hypothesis, temperature-sensitive data loggers were implanted subcutaneously into free-ranging black (Connochaetes gnou) and blue wildebeest (Connochaetes taurinus) from Mokala National Park and their orientation to solar radiation was determined visually. I found that when wildebeest were orientated perpendicular to solar radiation, there was a greater difference between the left and right subcutaneous temperature than when wildebeest were orientated parallel to solar radiation (t7=2.5, p=0.04). However, using subcutaneous temperature difference on its own to predict orientation to solar radiation could not account for how the previous orientation to solar radiation of wildebeest affected subcutaneous temperature patterns. Therefore, I designed a prediction model incorporating both subcutaneous temperature difference and rate of change in subcutaneous temperature difference to determine orientation to solar radiation. The prediction model was accurate more often than expected by chance (60 %), but there were many factors other than solar radiation that influenced subcutaneous temperature, which reduced the accuracy of the remote technique. Further research is necessary to improve the remote technique before it can be successfully used to study orientation to solar radiation. However, my study shows, for the first time, the potential of using subcutaneous temperatures to remotely detect orientation to solar radiation in ungulates. A remote technique to study orientation to solar radiation will be a great advantage for future studies on thermoregulatory behaviour. Because behavioural responses are likely to be an animal’s first defence against increased heat loads resulting from climate change, studying behavioural thermoregulation could provide important information for conservation and management decisions.Item Microclimate mosaic and its influence on behaviour of free-living African forest elephants (Loxodonta africana cyclotis)(2014-08-22) Kuwong, Michael ViyofAfrican elephants are known to survive in habitats with ambient temperatures from below 0°C to about 50°C, implying that they may be exposed to great thermal challenges, especially in hot regions of Africa, where they are common. Thermoregulatory behaviour of the African forest elephant in its natural habitat and the microclimates that it utilizes have not previously been investigated. To understand how such an enormous animal behaves in the hot, humid natural forest environment, I investigated microclimates at forest-savannah interfaces (bais) in Lobeke National Park in Cameroon, observed forest elephants’ likely thermoregulatory behaviour and correlated the behaviours with environmental microclimatic variables. Portable weather stations equipped with data loggers were deployed at five study sites to record microclimatic variables for three days per site. I used the fixed point sampling method to observe and record behaviours of forest elephants, during the hot, dry season. Black globe temperature reached an average of about 33ºC during the day in the bais and decreased to a mean of about 20ºC in the night. The day globe temperature often exceeded the body temperature of the elephants, but the vapour pressure of air was lower than that on the elephant’s skin. Therefore, at 100% humidity and estimated skin temperature of 35ºC, I assume elephants of this study lost heat by evaporation, both under the forest canopy and in the open bais. Wind speed in the bais was higher than that under the forest canopy, possibly facilitating convective heat loss from the elephants, particularly at night. Ear-flapping rate of the elephants correlated linearly and positively with dry-bulb and globe temperatures. Shade-seeking and dust-bathing only showed weak positive associations both with dry-bulb globe and temperatures. Between 06:00-24:00, elephants that were observed spent a mean of 40% of their time walking, 55% foraging, 7% shade-seeking, 45% ear-flapping, 4% dust-bathing and 9% of time performing water-related activities. The higher number of elephants in the bais at night as opposed to the numbers in the bais during the day, as revealed by the findings of this study, suggests that the forest elephant may have a more favourable mode of dumping its excess body heat in the open bais than under the forest canopy at night. All the bais and their vicinity that were investigated in this study were heavily trampled with elephant spoors, because many elephants frequently congregated in the area due the presence of nutritious herbaceous plants, mineral salts and variations in microclimates in the bai-savannah interfaces. The differences in microclimates in the bais and their vicinity may play a major role in influencing the forest elephant’s thermoregulatory behaviour. To the best of my knowledge, my study suggests for the first time that the forest elephant may use microclimates at the bai interface for thermoregulatory needs. However, my study is limited because it was executed for a short duration and over the hot dry season, and factors that may affect elephants such as physiology, the availability and quality of forage and predation risk were not included in this investigation. All these factors may have affected the accuracy of my findings. For these reasons the inferences made in this study on elephant microclimate selection would need further investigation before concrete conclusions are drawn. Expensive research cost, human safety, fear of human presence and hence alteration of elephant behaviour and the obscure nature of the equatorial forest have been recurrent issues hindering the investigation of behaviour of free-living African forest elephants. I suggest that it would be worthwhile investigating the forest elephant’s behaviour further by applying GPS/satellite telemetry, real time bio-logging and camera trap techniques, which offer a practical means to carry out an extensive study in the evergreen hot humid equatorial forest of the Congo Basin.