[Testicular activity of the ferret kept for over 4 years under permanent light and constant temperature]

Five male ferrets, aged 2 months, were kept in constant light (4-5 lx) and temperature (15 +/- 1 degree C) from July 1979 to September 1983. Under these experimental conditions, the testicular size displayed spontaneous variations. Four cycles, characterized by a marked testicular enlargement followed by an equivalent decrease, were observed in three ferrets. The two others exhibited only three spontaneous cycles. The mean interval between two successive maximums equalled 340 +/- 28 days.