The Effect of Irradiation With Different Wave-Lengths on the Oestrous Cycle of the Ferret, With Remarks on the Factors Controlling Sexual Periodicity

Abstract

ABSTRACT The ferret normally has a well-marked breeding season extending from about the middle of March until July or August, March 2nd being the earliest date in our experience for a normal ferret to come “on heat.” Oestrus in the non-occurrence of pregnancy or pseudo-pregnancy lasts a very long time and has been known to persist for 17 weeks. The condition is particularly easy to detect owing to the enormous swelling of the vulva which may be fifty times its anoestrous size. After ovulation which depends upon coitus the vulval swelling subsides as oestrus comes to an end. Pregnancy lasts about 42 days and there can be two gestation periods in the season (Marshall, 1904; Hammond and Marshall, 1930). The polecat in the wild state has a breeding season at approximately the same time as that of the ferret in captivity (Millais, 1905).