Ethanol changes patterns of defensive behavior in wild rats.

Wild-trapped R. rattus under saline or four ethanol doses were run in tasks designed to measure a range of defensive reactions to nonpainful threat stimuli. Results suggest that at higher doses (1.2 g/kg and above) ethanol reduces defense, with effects ranging from slight reductions to near abolition, depending on the behavior measured. Low and moderate ethanol (0.3 and 0.6 g/kg) doses, however, had divergent effects, tending to enhance components of the defensive attack pattern (vocalization, jump attacks, bites), while not altering other aspects of defensiveness. This pattern of results suggest that an ethanol-based potentiation of defensive attack may be one of the factors involved in the phenomenon of aggression increases following alcohol consumption.