[Adaptation of a 4-year-old chimpanzee to an unusual stimulus]

A complex of adaptive reactions have been observed in response to the unusual irritants in 4-year chimpanzee infant. It includes the orienting-research, passive defence reactions, avoidance of irritant, transfer on co-operation with experimenter, aggressive reactions to unusual irritants. The analysis of behaviour reactions and cardiac rhythm has revealed that playing with an experimentator and aggressive reactions are the most reliable way of adaptation which prevents strong and long emotional stress. A social system "chimpanzee-experimentator" on a positive parity basis is an important condition for promoting the appearance of the mentioned adaptation reaction.