The Parasol Tail and Thermoregulatory Behavior of the Cape Ground Squirrel Xerus inauris

Abstract
The Cape ground squirrel, Xerus inauris, a diurnally active inhabitant of hot arid regions of southern Africa, reduces environmental heat load by using its bushy tail as a portable parasol. During late spring in the southern Kalahari, operative environmental temperature ( ) was measured on thermal mannequins of differing posture and tail orientation. Simultaneously, the thermoregulatory behavior of a free-living colony of squirrels was observed. The tail is raised to shade the body and the squirrels turn their backs to the sun whenever exceeds approximately 40 C. The shade provided by the tail reduces by over 5 C and allows squirrels to extend greatly their periods of continuous surface foraging (up to 7 h instead of 3 h). At midday, squirrels must frequently retreat to their burrows as of tail-shaded animals then also exceeds 40 C.