Tests to determine the responsiveness of free-ranging Japanese monkeys in food-getting situations

Experiments were performed on a free-ranging Japanese monkey troop (Arashiyama-B troop) in order to study the various levels of response caused by excitement and the characteristics of each monkey's action as observed under a series of stimulating situations carried out step by step through the giving of peanuts to the monkeys in various ways. The following results were obtained: (1) Three types of responses, that is, Threat response, Fear response, and Negative response were observed. (2) In response types, fairly evident individual differences exist along side sexual and age differences. (3) Similarity of response tendencies were not readily recognizable between a mother and her children. (4) Between two sisters with a slight disparity of age, the younger showed a stronger threat response. (5) Among females more than 4 years old, the lower the rank, the stronger the fear response.