Potential stock differences in the social behavior of rats in a situation of restricted access to food.

The social behavior of outbred Long-Evans (LE) and Wistar (WI) rats was compared in a situation where access to food was particularly difficult (clearing an aquatic barrier, plus the necessity of carrying the food back to the home cage). In groups of either six WI or LE rats, only about 50% of individuals carried the food, and the others survived by attacking those that did. However, behavioral profiles associated with these acts were different in the two cases: LE carriers, contrary to WI carriers, restole some food, and LE noncarriers expressed more agonistic behavior and were more often attacked than were the WI noncarriers. Food flow and all associated, interactive behaviors were more complex in the LE than in the WI rats, indicating the likelihood of potential genetic differences in this testing situation.