Competitive and territorial fighting: two types of offense in the rat

Abstract

Two types of fighting (offense) were compared and contrasted in three experiments on the laboratory rat. In Experiment 1, competitive fighting was obtained in pairs of hungry cagemates by placing one food pellet into their food hopper. In Experiment 2, territorial fighting was obtained by introducing an unfamiliar intruder into the home cage of a male and female pair. Both types of fighting had the same motor patterns. Whereas territorial fighting is strongest against intruders of the same sex, competitive fighting is stronger against the smaller opponent (in this case female) regardless of the sex of the test animal. Whereas territorial fighting is stronger in males, competitive fighting is stronger in females. Whereas gonadectomy reduces territorial fighting in males but not females, it reduces competitive fighting in both sexes. In experiment three, it was shown that food deprivation increases competitive fighting, while it reduces territorial fighting. On the basis of these findings a revised model of the organization of the offense motivational system is proposed.