Mouse Killing Behaviour, Aggressiveness and the Influence of Sexual Hormones in Rats

Abstract

“Mouse-killing behaviour” is the behaviour of an isolated adult rat towards an anesthetized mouse placed in its cage; some rats (natural killer) spontaneously kill the mouse, others do not show any kind of aggressiveness.This interspecific aggressiveness, addressed to individuals of different species, is generally motivated by the instinct of predation. It can be distinguished by the intraspecific aggression,which is addressed to individuals of the same species, can have different motivations (establishment of a hierarchy, copulation, defence of territory) and can express itself with threats or real attacks, and can result in a dominant behaviour or in escape or in submission.