The pattern of feeding in a free-ranging troop of Japanese macaques reflected female rank. High-ranking females (HRF) obtained about 3/4 of their daily digested energy from artificial foods and 1/4 from natural sources, whereas low-ranking females (LRF) received roughly equal proportions of their daily digested energy from the two sources. LRF adjusted their feeding strategies in relation to seasonal variation of food supply. In winter, when food was scarce, dietary composition was dissimilar for HRF and LRF. The LRF strategy consisted of (1) finding new food resources and increasing the number of food items by 50%, (2) extending feeding time by 15%, while (3) reducing by 10% the time allocated to rest and social activities compared to HRF. In summer, when many fruits and seeds were available, dietary composition was similar, and the LRF strategy consisted of points 2 and 3 mentioned above. They also minimized agonistic interactions with HRF by reducing artificial food intake by 7 % and compensating with natural food.

The daily energy intake of provisioned Japanese monkeys was studied, particularly in the forest by focal animal sampling method. The study was conducted at Takasakiyama throughout a day for 5 days in March-April 1985 and 4 days in February 1986. The average metabolic body size (kg3/4) of randomly chosen focal animals was estimated to be 4.12kg3/4 (March-April) and 3.66kg3/4 (February). The daily enegy intake from natural food in the forest was 139.7kcal/kg3/4 (March-April) and 75.0kcal/kg3/4 (February). While at the artificial feeding ground, it was 98.7kcal/kg3/4 (March-April) and 102.6kcal/kg3/4 (February). Daily digestible energy was calculated as 83.8kcal/kg3/4 from natural food and 85.9kcal/kg3/4 from the artificial food in March-April, and, 41.3kcal/kg3/4 and 89.3kcal/kg3/4 in February, if digestibility of natural food in March-April and February (leaves occupied 60%) was calculated as 60% and 55% respectively, and that of artificial food was 87%. Daily energy consumption was calculated to be 98.7kcal/kg3/4 (March-April) and 92.5kcal/kg3/4 (February) from activity record. Daily excessive energy was estimated to be 71.0kcal/kg3/4 (March-April) and 38.1kcal/kg3/4 (February). The daily digestible energy was more than the daily energy consumption in March-April as well as in February. This study suggests that excessive energy intake is used for growth, reproduction and activities for Japanese monkeys at Takasakiyama.