ON THE DUAL NATURE OF MATERNAL AGGRESSION IN RATS

Presentation of a natural predator, a cat, was used to differentiate e lements of maternal attack by female rats on a male intruder. Followin g exposure (without direct physical contact) of post-partum females to a cat or to a toy stuffed cat (control group), the females mere repla ced in their home cages and presented with a male intruder rat. Cat ex posure reliably decreased lateral attack to the intruder, as well as l ocomotion, but had no effect on either jump attack or an upright defen sive posture (boxing). Since predator exposure produces a somewhat dur able increase in defense, along with inhibition of nondefensive behavi or, these results suggest that maternal aggression represents a mixtur e of offensive, usually related to competition, and defensive (protect ive) behaviors. The results indicate that maternal aggression, as a pa rental care behavior, appears to be at least partially resistant to fe ar. (C) 1996 Wiley-Liss, Inc.