Models of Early Hormonal Effects on Intrasex Aggression in Mice

Abstract

Aggression is a term that has been applied to many different types of behaviors, from hostile language and gestures to physical violence (Buss, 1961). Aggression, as used here, will refer to a category of behaviors associated with physical attack by one house mouse (male or female) on another mouse of the same sex. This type of aggression is therefore most appropriately referred to as “intrasex” aggression. But conspecific aggression in mammals is often referred to as “intermale” aggression, since fighting is generally considered to be a trait characteristic of males and uncharacteristic of females. An exception to this general statement has been the recognition that many, but not all, female mammals exhibit aggression during the postpartum period in defense of their young (Svare, 1981). It is important to recognize that other types of conspecific aggression (e.g., fear-induced aggression, sex-related aggression, infanticide) are commonly observed in many mammals. These other forms of conspecific aggression are influenced by variables different from those that influence either intermale or interfemale aggression (Moyer, 1974). For example, when a nonreceptive female mouse is placed into the home cage of a sexually experienced adult male, the male will attempt to mount the female and the mounting attempts will be rejected. As a result, the male often becomes highly aroused and attacks the female (vom Saal & Bronson, 1978).