Adaptation of Some Large North American Mammals for Survival In Snow

Wolves (Canis lupus), coyotes (C. latrans), and a wolverine showed similar levels of morpho- logical adaptation to snow, higher than all but two of the ungulates studied; predation appears to have been a factor influencing evolution of ungulate behavior in snow.

Abstract

Chest heights, foot loading, and behavior of moose (Alces alces), caribou (Rangifer tarandus), wapiti (Cervus canadensis), white—tailed deer (Odocoileus virginianus), Dall sheep (Ovis dalli), bighorn sheep (Ovis canadensis), pronghorn antelope (Antilocapra americana), and bis (Bison bison) were used to calculate indices of snow—coping ability for each species. When species were grouped into regional faunas, those with higher indices occurred in more snowy regions. Within a local area, a variety of species can survive in winter by living and feeding in different habitats defined on the basis of snow conditions. Bison, deer, and wapiti have considerable sexual dimorphism in chest height and foot loading. These differences between the sexes have potential value for individual survival in snow by permitting use of food resources over a greater proportion of the species' home range. Wolves (Canis lupus), coyotes (C. latrans), and a wolverine (Gulo luscus) showed similar levels of morphological adapation to snow, higher than all but two of the ungulates studied (caribou and moose); predation appears to have been a factor influencing evolution of ungulate behavior in snow.