Activity differences of individually and group-housed male and female rats

Abstract

Previous comparisons of the activity differences of individually and group-housed rats have produced inconsistent findings; therefore, we examined activity using three measures: open-field ambulation, nonspecific circadian activity, and rearing behavior. Open-field ambulation in two 5-day tests confirmed our prediction that isolates would be initially less active but later more active than group-housed rats. Isolates habituated more slowly to the activity monitor and tended to be more active during the light half of the 24-h cycle. In the rearing test, isolates showed elevated and more persistent activity than group-housed rats. All these activity differences were prevalent in both male and female rats. The results are interpreted in terms of the influence of differential housing on "fear responses," exploration of a novel environment, and differences in habituation/adaptation processes. © 1981 Psychonomic Society, Inc.