Mousekilling in virgin, pregnant and lactating rats

Abstract

Past studies on the social reactions of female rats to mice typically involved the presentation of mice for long periods of time either before or during gestation. Under these conditions, it was not possible to separate the effects of mere exposure to pups from the profound neuroendocrine changes accompanying gestation. A more suitable paradigm would have been one that varied reproductive state independent of exposure to young. Virgin, early and late pregnant, and early lactating (N = 20 in each) Sprague-Dawley rats were presented therefore with a mouse for 30 min a day for 2 consecutive days. Mousekilling was observed on only two trials. There was no maternal behavior. Generally, rat and mouse ignored each other, even when rat pups lived with lactating rats. It was suggested that to better assess the effects of reproductive state on predation, studies are needed that vary strain (use of high mousekillers), hunger conditions, and the type of mouse. © 1974.