Reproduction in the wolverine, Gulo gulo

Wright, Philip; Rausch, Robert

The reproductive tracts of 22 male and 11 female wolverines taken mostly during the fall, winter, and early spring months in northern Alaska have been studied. Adult females taken in October, November, and January showed unimplanted blastocysts in their uteri and inactive corpora lutea in their ovaries. The blastocysts ranging in number from two to four per female were recovered. The blastocysts may have several hundred cells and they are about 2 mm. in diameter. A late-January and an early-February specimen had implanted embryos of 22 and 68 mm. crown-rump length respectively. Two early-April specimens were lactating but not pregnant. Four females were immature. The wolverine has a long period of gestation like many of the other mustelids. The breeding season is not precisely known but it probably occurs in mid-summer. The baculum of the male is described. Immature males may be distinguished from adult males by their smaller bacula. The testes of males of both ages were largely inactive during the winter months. Full sexual activity was seen in only one male taken in early April. The skull of the wolverine matures rapidly, but the young during the first year tend to show open sutures in the facial and zygomatic regions. The sagittal crests of first year animals do not extend as far posteriorly as do those of adults.

Reproduction in the wolverine, Gulo gulo

Series