The effects of individual housing on 'anxious' behaviour in male and female gerbils.

Gerbils are social animals and live in family groups in the wild, suggesting that individual housing may be a psychosocial stressor in this species. In the present study, gerbils were housed in same sex groups for 4 weeks, and then were either individually housed or remained with their cage mates for 1 week. Gerbils were tested in the black/white box (BWB), elevated plus maze (EPM) and social interaction test. Results indicated no significant differences in behaviour in the BWB. In contrast, on the EPM individually housed males showed increased anxiety compared to other groups, whilst there were no specific effects in females. In the social interaction test, however, individual housing in males increased social investigation, whilst females showed a decrease in exploration, accompanied by increased immobility. Passive immobility (freezing) was also increased in both sexes following individual housing. Thus, data from the EPM suggest that individual housing leads to increased anxiety mainly in males, whilst data from the SI suggests broadly the opposite. Therefore, individual housing results in different behavioural changes in male and female gerbils, which are dependent upon the test situation. This study highlights two key points. Firstly, it is important to use our knowledge of the species natural ecology in interpreting and designing anxiety tests. Secondly, it is important to assess behaviour in a range of situations when attempting to measure 'anxiety', particularly where tests developed for use in one species/sex are being used in another.