No effects of huddling on core body temperature in rock hyrax, Procavia capensis

Abstract

Huddling is a behavioural energy conservation mechanism that is widely used by  many small endotherms at low ambient  temperatures. Huddling has many benefits, including decreasing the metabolic cost of maintaining body temperature (T_b),  reducing the amount of heat lost to the environment, and increasing the local temperature of the nest. To test the effects of huddling on T_b, 10 rock hyrax, Procavia capensis, were housed in outside cages in four groups, varying from one to four individuals. iButtons® were surgically implanted into each rock hyrax to record their Tb every 15 min from August to November. Despite  considerable variations in ambient temperatures, the rock hyrax were found to display some degree of heterothermy by varying  their mean T_b from 36.70 to 37.72°C (n = 10) but not allowing it to drop below 33.60°C or rise above 39.67°C. Contrary to what was predicted, rock hyrax did not display any significant effects of huddling on T_b, irrespective of group size.

Key words: rock hyrax, Procavia capensis, huddle, energy conservation, body temperature.