Sex Differences in Foraging Behaviour, Body Fat and Hibernation Patterns of Free-Ranging Common Hamsters

Abstract

In this study, we investigated foraging behaviour, body fat and hibernation patterns in adult common hamsters (Cricetus cricetus). In addition, we compared the proportion of body fat prior to hibernation between adult and juvenile individuals. We investigated a population of free-ranging common hamsters in an urban area in southern Vienna, Austria. We applied capture-mark-recapture techniques and focal-animal-sampling for behavioural recordings. Body fat was calculated by integrating morphometric parameters. Body temperature changes were recorded during winter using subcutaneously implanted data loggers. We calculated the time individuals spent in torpor, the number and length of torpor bouts. The results revealed sex differences in foraging behaviour, in that males were feeding mainly above ground, whereas females almost exclusively cached food. These potential differences in energy allocation prior to winter were reflected in body fat at the end of the active season. Adult males had a higher proportion of body fat than females. Although juveniles had lower body fat than adults, similar sex differences were found. During winter adult males spent more time in torpor than females, indicating differing overwintering strategies depending on the individual potential to allocate internal or external energy reserves.