Thermoregulation, hibernation and reproduction in the South African hedgehog Erinaceus frontalis A. Smith

Abstract

The relationship between oxygen consumption (Vo2), ambient temperature (Ta) and body temperature (Tb) in the South African hedgehog (Erinaceus frontalis) was recorded in spring (September- October 1986), autumn (March-April 1987), winter (July-August 1987) and summer (November- December 1987). In spring the hedgehogs were unable to maintain their body temperature at an ambient temperature of 1O°c. At a temperature of 35°c the body temperature was measured as 40°C and the animals could not tolerate this high temperature. The lowest mean oxygen consumption measured during the different months ranged from 0.39 ± 0,03 ml 02(g.h.)-1 in autumn to 0,54 ± 0,08 ml 02(g.h.)-1 in summer. The body mass of the hedgehogs reached a maximum in April and a minimum in August. It appears as if the South African hedgehog has the ability to hibernate. Non-shivering thermogenesis does occur in this species. During July when the ambient temperature dropped to 8 °c the frequency of activity was low. During the following sessions the frequency of activity became increasingly higher. Aspects of maternal behaviour, growth and development of young from birth to weaning, and dispersal were recorded during three 24-hour observation sessions. The young of the two females studied, spent less time at huddling and suckling and more time alone in the nestbox and walking outside the nestbox with the mother when they reached the age of about 30 days. At an age of 44 days they were weaned. Litter size recorded during this study ranged from 1 - 11 (n = 6). Seasonal changes in plasma testosterone and plasma progesterone levels during a one year period were determined. From September to January the arculating levels of testosterone were high while low levels were recorded from February to June. Testicular activity resumed at the end of winter when the hedgehogs were still hibernating. The existance of a substance that binds testosterone was confirmed. In the females, cylic ovarian activity started at the end of August. Plasma progesterone levels peaked during September and October. Aspects of the oestrous cycle of the female hedgehog were determined by progesterone levels in urine. These levels showed that the three females studied, had three or more oestrous cycles during the breeding season.