Burying as a defensive response in rats.

Abstract

In typical laboratory settings, the defensive reactions of animals appear to be limited tofreezing, fleeing, and attacking.However, in the present investigations, rats.tested in the presence of movable ma-> terial incorporated it into a striking and adaptive behavioural sequence.Rats shocked once through a stationary prod buried this shock ^source, even when the shocks-test interval was 20 days.This burying behaviour occurred at a variety of shock intensities and seemed to be controlled sp cifically by the relation between the shock and the prod; rats shocked through a grid did not bury the prod, and rats shocked by one of two identical prods buried only the shock-prod.Both the position and bright ness of the prod seemed to control the burying behaviour.When either of these cues was changed prior to the test, burying behaviour was disrupted compared to control conditions in which these cues were unaltered.Although burying was a directed and consistent response of rats to prod shock, it was not a simple, reflexive behaviour; rats could adapt their burying behaviour to changes in both the kind and disposition of burying materials.Thus, the usual assumption that the rat's defensive reper^toire is limited to a few simple behaviours appears to have been shaped by the constraints of standard testing environments rather than by the actual propensities of the rat.These results were discussed in terms of their implications for a "biological" approach to aversive learning.