The influence of body mass on daily movement patterns and home ranges of the collared lemming (Dicrostonyx groenlandicus)

While the determinants of animals' space use have been addressed in a large number of studies, its intrasexual variability has received only limited attention. By means of radiotelemetry we found body mass to influence home-range size and distance moved by adult collared lemmings (Dicrostonyx groenlandicus) in northeast Greenland. Male body mass was positively correlated with home-range size. Distance moved by both males and females was also correlated with body mass, but with opposite trends: male movement distances increased with body mass, while female movement distances decreased. This may reflect the fact that larger females occupy the most favourable habitats, i.e., the habitats that minimize the need for movement, and thus exposure to predators, without limiting the food supply. The variability in male home range size and distance moved resulted in variability in the number of females accessible to each male. Larger males had access to more females, and hence, body mass was indirectly important for individual mating opportunities. However, increasing access to females was associated with higher costs in terms of mass loss, probably as a consequence of increased energy requirements and exposure to predators.