Sex Differences in Seasonal Changes of Brown Adipose Tissue and Activity of the Australian Vespertilionid Bat Eptesicus vulturnus

Abstract

Information on seasonal changes in activity, body weight and brown adipose tissue weight was collected from a wild population of a small Australian vespertilionid, Eptesicus vulturnus. Both sexes, but especially females, became less active during the colder months of the year. Males maintained body weight and brown adipose tissue weight during winter, as do non-hibernating mammals. Females lost brown adipose tissue and body weight during winter, as do hibernators. The relationship between the sex differences in overwintering behaviour and the reproductive cycle is discussed.