Lack of increased intermale fighting behavior in mice after low ethanol doses.

The effect of ethanol on intermale fighting behavior, measured mainly as the total fighting time, was studied using Swiss-Webster mice in 5-min encounters in a neutral arena (i.e., not the home cage). Ethanol treatment compared to control treatment had no statistically significant effect on fighting behavior when given to both equal-sized members of a pair of males socially isolated for a) 5 or 10 days at a dose of 0.4 g/kg IP; b) 4 weeks at 0.8 g/kg IP; and c) 38 weeks at 0.4 g/kg IP. Moreover, no significant effect was found when ethanol was given only to the expected dominant member of a pair, that is, to: a) a male isolated for 48 weeks confronting a younger and smaller group-housed male at 0.4 g/kg PO; and b) a male that had been pair housed with a female conspecific for 5 weeks confronting a group-housed male of equal age and weight at 0.4 g/kg IP. The results suggest that under these conditions ethanol does not lead to increased fighting behavior in Swiss-Webster male mice.