ENDOCRINE CORRELATES OF THE ANNUAL REPRODUCTIVE CYCLE OF THE PORCUPINE Hystrix africaeaustralis

The Cape porcupine Hystrix africaeaustralis is a large (12-18 kg) nocturnal hystricomorph rodent occurring throughout southern Africa where it is sometimes used as a source of food and often regarded as a nuisance by crop-producing fanners. They live in family groups, these generally comprising an adult male, adult female and varying numbers of offspring of successive litters. Reproduction is characterized by a relatively long oestrous cycle (-30 days) and gestation period (94 days). Captive females breed throughout the year but free-ranging females in southern Africa only produce litters in summer when exposed to seasonal climatic changes (van Aarde, 1985a). The present paper reports on seasonal changes in plasma progesterone and oestradiol­ 17jJ levels in adult females and seasonal changes in plasma testosterone levels in adult males in an attempt to explain the annual reproductive pattern of porcupines.