Oral presentation- Open Session 12th International Mammalogical Congress

Sable antelope display flexibility in body temperature regulation and behavioural patterns during the dry season (#502)

Kiara A. Haylock 1 , Francesca Parrini 1 , W. Maartin Strauss 2 3 , Piet Beytell 4 , Carl-Heinz Moeller 4 , Robyn S. Hetem 2 5
  1. Centre for African Ecology, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa
  2. Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa
  3. Department of Environmental Sciences, University of South Africa, Johannesburg, South Africa
  4. Directorate of Natural Resource Management, Ministry of Environment and Tourism, Windhoek, Namibia
  5. School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa

The dry season is a stressful period for antelopes since reduced resource availability may exacerbate thermal stresses. Sable antelope (Hippotragus niger) exhibit behavioural flexibility in range extent and activity during the dry season, but it is unknown whether such behavioural flexibility completely buffers the restricted resource availability. Over an eight month period, we measured body temperature and locomotor activity using biologging and determined home and core range extent of seven free-living GPS collared sable in the semi-arid Zambezi region of Namibia, one of the more arid regions within sable’s distribution range. Sable increased their home (F4,6=8.3, p=0.0002) and core (F4,6=6.2, p=0.0014) range extent during the dry period with ranges peaking in size (home range: 17.6±7.5km2; core range: 1.9±0.8km2) following rainfall. Sable decreased diurnal activity by ~58% when conditions were hot and dry (F4,6=41.8, p<0.0001), without altering total 24-hour activity (F4,6=1.0, p=0.4226). Despite these behavioural changes, we observed perturbations in the body temperature rhythms of sable during the dry season with a reduction in 24-hour minimum body temperature during cool-dry conditions (F4,6=8.5, p=0.0002) and an increase in 24-hour maximum body temperature during hot-dry conditions (F4,6=11.7, p<0.0001). Consequently sable displayed larger 24-hour amplitudes of body temperature rhythm during resource-limited dry periods, with 24-hour body temperature amplitude reaching 4.3ºC on occasion, compared to resource-adequate periods following rainfall where sable maintained homeothermy (F4,6=11.2, p<0.0001). This study provides initial evidence for stress-related changes in body temperature regulation of sable antelope during the dry season despite behavioural plasticity.