Living on the edge: Daily, seasonal and annual body temperature patterns of Arabian oryx in Saudi Arabia

• Published in: PloS one Vol. 12; no. 8; p. e0180269
• Main Authors: Streicher, S, Lutermann, H, Bennett, N C, Bertelsen, M F, Mohammed, O B, Manger, P R, Scantlebury, M, Ismael, K, Alagaili, A N
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 30-08-2017; Public Library of Science (PLoS)
• Subjects: Analysis; Animal reproduction; Animals; Arid environments; Aridity; Artiodactyla - physiology; Biology and Life Sciences; Body Size; Body Temperature; Body Temperature Regulation; Brain research; Competition; Daytime; Desert Climate; Deserts; Dissipation; Earth Sciences; Ecology and Environmental Sciences; Endothermy; Environmental effects; Evaporation; Female; Food; Free water; Gender aspects; Homeostasis; Intrinsic factor; Male; Males; Medicine and Health Sciences; Metabolism; Night; People and places; Physiology; Rainfall; Reproduction (biology); Saudi Arabia; Seasons; Sex; Sex differences; Sexual behavior; Soil investigations; Soil stresses; Soil temperature; Soil water; Temperature; Temperature effects; Temperature patterns; Ungulates; Water availability; Water conservation; Water loss; Water shortages; Water stress; Zoology; Saudi Arabia; Riyadh Saudi Arabia
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0180269

Heterothermy, the ability to allow body temperature (Tb) to fluctuate, has been proposed as an adaptive mechanism that enables large ungulates to cope with the high environmental temperatures and lack of free water experienced in arid environments. By storing heat during the daytime and dissipating it during the night, arid-adapted ungulates may reduce evaporative water loss and conserve water. Adaptive heterothermy in large ungulates should be particularly pronounced in hot environments with severely limited access to free water. In the current study we investigated the effects of environmental temperature (ambient, Ta and soil, Ts) and water stress on the Tb of wild, free-ranging Arabian oryx (Oryx leucoryx) in two different sites in Saudi Arabia, Mahazat as-Sayd (MS) and Uruq Bani Ma'arid (UBM). Using implanted data loggers wet took continuous Tb readings every 10 minutes for an entire calendar year and determined the Tb amplitude as well as the heterothermy index (HI). Both differed significantly between sites but contrary to our expectations they were greater in MS despite its lower environmental temperatures and higher rainfall. This may be partially attributable to a higher activity in an unfamiliar environment for translocated animals in UBM. As expected Tb amplitude and HI were greatest during summer. Only minor sex differences were apparent that may be attributable to sex-specific investment into reproduction (e.g. male-male competition) during rut. Our results suggest that the degree of heterothermy is not only driven by extrinsic factors (e.g. environmental temperatures and water availability), but may also be affected by intrinsic factors (e.g. sex and/or behaviour).