Some studies on the influence of chlordiazepoxide on the social interaction of golden hamsters (Mesocricetus auratus).

1. The effects of a ;minor' tranquillizer (chlordiazepoxide) on the social behaviour of male golden hamsters were investigated.2. Thirty-six hamsters were divided into pairs. Each pair was placed in an arena measuring 1 m(2); under these conditions the hamsters fought, but once a winner and loser emerged the relationship between the two animals became stabilized. The influence of 50 mg/kg chlordiazepoxide on this stable relationship was investigated and compared with normal behaviour in the arena.3. Under the influence of chlordiazepoxide, hamsters showed a significant reduction in ;aggression', ;defensive fighting' and an increase in ;investigation'.4. When the data for winners and losers were analysed independently, the drug was seen to influence losers more than winners.5. It is postulated that the primary influence of chlordiazepoxide is to reduce fear and as a result ;investigation' is probably affected indirectly as a behaviour pattern suppressed in an individual showing fear of its opponent.