Quantitative study of activity patterns and postures of formosan monkeys by the radio-telemetrical technique

Twenty-four hours locomotive activity and posture of four formosan monkeys were recorded continuously by radio-telemetrical technique. (1) The movement activity were drawn; during day time the activity peak and valley come alternatively. They have three-five activity peak per day. (2) Average of time spent in movement is only 1 hour and 8 minutes however frequencies of movement are very high, average is 557.0 per day. (3) Measured the time spent in and the frequency of orthograde and pronograde posture; orthograde posture occupies 20 hours and 10 minutes. These results signify monkeys are sitting for 84% of the day. The frequency of change posture (moving, sitting, and lying) shows 1477.8 times a day on the average. (4) Observing the social interactions and self-directed responses, behavior pattern were analyzed.The fact that monkeys take the orthograde posture for 84% has a very important evolutionary meaning. Sitting posture (orthograde) is an adaptive behavior derived from arboreal life. The orthograde posture that put on a social basis of fundamental physical condition for bipedalism has already prepared in the forest life.Grant in aid for special project research No. 92031.