Sexual segregation in moose: effects of incisor morphology, quality of willows, and foraging behavior

Abstract

Differences in the jaw morphology of Alaskan moose (Alces alces gigas) may relate to sexual segregation. Male Alaskan moose had significantly wider incisor breadths than did females; however, incisor depth did not differ between sexes. Those differences in jaw architecture might relate to the diets of sexes when they are spatially segregated. Moose consume willow (Salix spp.) as a fundamental component of their diet. Smaller-diameter twigs were more digestible, had more protein, and contained less fiber than larger-diameter twigs. Conversely, no relation existed between age of twigs and digestibility. Ruminants may segregate spatially because females competitively exclude males. An experiment on foraging behavior, however, rejected that hypothesis. Nonetheless, females fed more selectively and had higher rates of forage intake than did males. Thus, differences in foraging behavior between the sexes still may relate to sexual segregation.