Evaporative water loss in two small African antelopes: the dik-dik and the suni

Abstract

1.

1. In controlled laboratory experiments pulmocutaneous water loss, respiratory rate, rectal and skin temperatures of the dik-dik (Rhynchotragus Kirkii) and the suni (Nesotragus moschatus) were measured before and during exposure to heat stress. 2.

2. During exposure to thermal stress (Ta > 40°C) increases were noted in all measured parameters except sweating rate in both species. 3.

3. In both dik-dik and the suni antelopes, sweating did not appear to be an important avenue of evaporative heat loss during heat exposure. 4.

4. Intradermal injections of adrenaline and noradrenaline stimulated sweating while injections of acetylcholine, carbachol, prolactin, oxytocin and isoprenaline had negligible effects on sweating.