Notes on Ovulation and Fertilisation in the Ferret

1. The ferret ovulates normally about 30 hours after coitus. 2. The average duration of coitus is about 2 hours but varies from ¼ hour to 3 hours. There was no evidence that short copulations were less fertile than long ones. 3. For 36 hours after coitus the vulva remains turgid, but becomes flaccid by about 60 hours after coitus, presumably from absence of oestrin. 4. Spermatozoa reach the upper part of the uterus within about 3 hours after coitus, but during this time do not reach the ovarian capsule. Spermatozoa were found in the ovarian capsule 6 hours after coitus. No spermatozoa were found in the ovarian capsule or uterus 10 days after coitus. 5. An attempt to determine the possible duration of fertilising capacity of the spermatozoa in the female tract was made, but no conclusive results were obtained owing to the difficulty of performing artificial insemination in the ferret. 6. In the ferret the ovum remains capable of fertilisation for not more than 30 hours after ovulation. From 18 to 30 hours after ovulation only a small proportion of the ova remain capable of fertilisation, and small litters are produced from matings made at this time.