Effects of ethyl alcohol on development and social behaviour in the offspring of laboratory mice.

Behavioural and developmental effects of exposure to a low level of ethyl alcohol from conception to adulthood have been examined in mice. A 5% solution of alcohol in the drinking fluid of male and female adults did not impair fertility. The offspring of treated mice were significantly lighter at birth than their controls and remained so throughout their life span. No congenital malformations were observed. Behaviour of the offspring 3--4 weeks of age and in adulthood was examined by ethological analysis of encounters between alcohol-treated and control mice of the same sex. In male and female juvenile mice receiving 5% alcohol, the frequency and duration of social investigation were significantly lower than those of control partners and the duration of non-social behaviour was raised. Individual elements of 'investigate' and 'sniff' were significantly reduced in frequency. In alcohol-treated adults, the only behavioural difference from controls was an increased frequency of flight elements occurring in males. It is suggested that long-term exposure to alcohol may lead to behavioural adaptation.