The study of social interaction between small animals

Abstract

Summary An enclosure and automatic long-period monitoring techniques are described for the study of social interactions between small mammals. The durations and time and amount of eating, drinking, food hoarding, wheel running, ambulatory and exploratory movements, crossing of a passage, entering and leaving a nest, and sleeping, are recorded together with semiautomatic data reduction of correlations. To illustrate the utility of the techniques, exploratory studies were carried out with two mature Peromyscus maniculatus females, first living alone and then living together. The animals were identified automatically by means of ferromagnetic proximity sensing of small metal collars. When living alone, each animal displayed a distinctive behaviour pattern. When placed in consort, the activities of both changed markedly, particularly during the first few days. Both animals eventually settled into a regular routine in which each tended to draw nearer to the behaviour pattern of the other. Thus, animal No. 13, very active when alone, became less active, while No. 8, relatively inactive when living alone, became more active. A tendency of the animals to remain in each other's company also was evidenced. Changes in behaviour was demonstrably dependent upon social interactions, for when the animals were returned to a solitary existence, each returned to essentially its previous pattern of activity.