Degrees of captivity and aggressive behavior in domestic Norway rats

Abstract

Six categories of aggressive behaviors were studied in groups of domestic rats observed for 3 months and in three settings of varying degrees of captivity. In the least captive situation, a large outdoor pen, aggression frequently took a wild-type form (aggressive side postures, biting attacks) and infrequently took a “playful” form (pins, aggressive grooms) relative to aggression shown by rats in the most captive situation, laboratory cages. Rats housed in an intermediate degree of captivity showed intermediate levels of both serious and playful types of aggression. Male and female intruders were attacked by residents of all three settings, most seriously in the outdoor pen. These results indicate that captivity may have a powerful effect on the form of aggression shown by domestic rats. © 1983, The psychonomic Society, Inc.. All rights reserved.