A comparison of prey eating by spontaneous mouse killing rats and rats with lateral septal, medial accumbens, or medial hypothalamic lesions.

Rats with lesions of the medial hypothalamus and spontaneous mouse killing rats were tested for mouse and rat pup killing in their living cages 1 and 3 days postoperatively. The lesioned and spontaneous killers did not differ significantly in amount of prey eaten within 10 min following a mouse kill on either Day 1 or 3 postoperatively. Both groups ate significantly more of the prey than did sham-lesioned rats that were presented with a freshly killed mouse. When 4 hr was allowed for eating following a kill, rats with lesions of the lateral septum, medial accumbens, and medial hypothalamus each ate significantly more than spontaneous mouse killing rats. The greater prey eating by the lesioned animals is probably not the result of the prey being a highly palatable food since rats with medial hypothalamic lesions but not those with medial accumbens or septal lesions showed enhanced consumption of a sweetened lab chow over a 4 hr period. The quantitative similarity in the prey eating by spontaneous and lesion-induced mouse killers in the period immediately following the kill serves to further establish a relationship between these two kinds of killing. The greater eating that occurs in lesioned animals when a longer time is allowed for eating is consistent with other observations of excesses in the killing behavior of lesioned animals relative to spontaneous killers.