Animals that inhabit unfavourable habitats and experience seasons where the cost of maintenance exceeds the available energy resources have over time developed behavioural and physiological mechanisms to survive. These adaptations include changes in activity, improvement of cold tolerance by using nonshivering thermogenesis (NST), improvement of thermal conductance, reduction of body mass, or acclimation to colder temperatures (reduction of metabolic requirement). In addition some species exhibit heterothermy, in the form of either daily torpor or longer-term hibernation. The southern African hedgehog (Atelerix frontalis) is an excellent candidate to investigate the phenomenon of heterothermy because it is a small insectivore (summer body mass ca. 300 to 400g), burrows, inhabits harsh habitats and is not easy to find during the winter months. In this study I aimed to investigate whether A. frontalis exhibits seasonal differences in metabolic rate and furthermore if this species exhibits heterothermy. The study was carried out in the Northern Cape Province, South Africa. Hedgehogs were hand captured and their metabolic rates were measured using indirect calorimetry. Individuals were implanted with temperature dataloggers for a summer period (November 2009-January 2010) and a winter period (May-August 2009). The summer BMR of adult A. frontalis (0.448 ±0.035 mlO2/g/h, n=4) was significantly lower than their winter BMR (0.811 ±0.073 mlO2/g/h, n=4) and statistical analyses revealed that this was an affect caused by seasonal changes in the ambient environment. Individuals spent up to 84 percent of time during the measurement period torpid (-8°C <Ta<21°C). Body mass appears to be an important factor in determining the pattern of heterothermy (daily torpor versus hibernation) used in this species. To my knowledge the extremely low body temperature (Tb min) of 1.0°C recorded for A. frontalis is the lowest Tb min recorded for a mainland Afrotropical mammal. This species displays classic up-regulation in metabolic rate during winter, resulting in an increase in the energetic requirements of the species. As a result, heterothermy appears to play a significant role in the energy balance of this species during winter, contributing to energy saving. Heterothermy may enable this species to survive in the face of global climate change.

The near-threatened southern African hedgehog, Atelerix frontalis (A. Smith, 1831) is divided into two subspecies based on its disjunct distribution of two allopatric populations. This is despite reservations because its nature and extent of geographic variation remains virtually unknown. The present study, therefore, represents the first analysis of geographic variation within A. frontalis and is based on a multidisciplinary approach involving traditional and two-dimensional geometric morphometric analysis of the cranium and mandible, and molecular data in order to test the validity of the subspecies designations. The results of all univariate and multivariate analyses of both traditional and geometric morphometric data were congruent and provide evidence for a north-westerly–south-easterly clinal pattern of variation with cranial configuration being positively correlated with both latitude and longitude. These results are supported by Neighbour-joining, Maximum Likelihood, and Maximum Parsimony analyses of Cyt-b and ND2 data that revealed no variation across a 377 bp and 1034 bp region sequenced for each gene, respectively, while a 377 bp control region sequenced revealed low levels of variation between representatives of the two recognized subspecies (0.54 % pairwise sequence divergence). These results together with the lack of pronounced steps in the clinal pattern of variation suggest that the recognition of subspecies within A. frontalis may be untenable such that its disjunct distribution may represent a recent divergence event. If this is the case, then the results in this study may have implications in the conservation management strategies for A. frontalis, since it could be argued that one disjunct population could act as a source population for the other. However, it is recommended that prior to the implementation of conservation management plans for the species, further studies involving a wide range of alternative systematic techniques need to be undertaken first in order to gain a better understanding of the nature and extent of geographic variation within A. frontalis. These suggested studies should focus on comprehensive sampling and analyses involving a range of environmental and/or climatic variables in an attempt to identify factors that may explain the disjunct distribution and the clinal pattern of variation within the southern African hedgehog. / Dissertation (MS)--University of Pretoria, 2011. / Zoology and Entomology / unrestricted