Effect of hyperthermia on heat balance during running in the African hunting dog.

TAYLOR, C. R., KNUT SCHMIDT-NIELSEN, RAZI DMI’EL, AND MICHAEL FEDAK. E$ect of hyperthermia on heat balance during running in the African hunting dog. Am. J. Physiol., 220(3): 823-827. 1971 .-The tricolored Cape hunting dog (Lycaon pi&s) is a doglike African carnivore. It hunts in packs and tirelessly runs down its prey. In experiments at 26 C, the running hunting dog had a higher rectal temperature than the domestic dog and lost a smaller percentage of its heat production by respiratory evaporation. For example, at 15 km hr-l and 26 C the hunting dog’s rectal temperature was 41.2 C =t 0.05 and it lost 25.1% of= 0.5 of its heat production by respiratory evaporation; the corresponding figures for the domestic dog were 39.2 C rt 0.03 and 49.7% h 3.0. At rest, however, the hunting dog, like the domestic dog, increased respiratory evaporation and maintained a nearly constant rectal temperature at high air temperatures (up to 41 C). We designed experiments to measure the combined effect of 20 min running plus 40 min recovery on heat production and avenues of heat loss. In the hunting dog, even at 41 C, 407, of the additional heat generated by the run was lost without evaporation. The hunting dog’s low evaporation while running might increase the distance it can pursue its prey.