Fecundity of Female Wolverine in Montana

Abstract

We collected carcasses from trapper-harve ted wolverine (Gulo gulo) in Montana from 1984 through 2005 to evaluate pregnancy rates and corpora lutea production as an estimate of wolverine fecundity in eco-regions and subpopulations of western Montana. Pregnancy rates in the northwest eco-region were 100 percent for adults (n =11) and 30 percent for subadults (n=15). Pregnancy rates within the southwest eco-region were less than observed in the northwest (67.8% for adults, n =28; and 12.5 % for subadults, n = 16). We observed similar results in subpopulations from northwestern and southwestern Montana. Median corpora lutea counts for pooled adult and subadult females also differed among eco-regions being greater in northwest (median = 3.0, n = 26) than the southwest (median = 0.0, n = 44 ). Litter sizes and measurements of recovered fetuses are also presented. Comparisons of our data to similar studies in North America suggested adult pregnancy rates and mean litter sizes observed in the southwestern eco-region of our study area are the lowest reported in the literature.