Japanese macaques are generalist omnivores, and their diets change seasonally. During the summer, especially June and between September and November, they mostly eat fruits. They also eat seeds, although seeds account for less than 20% of their food intake during these months. During April and May and from December to March, Japanese macaques eat mostly flowers and some nectar. During the winter months, a large part of their diet consists of fibrous mature leafs. They also consume young leafs, which are easier to digest, from April to June. Japanese macaques also opportunistically eat fungi.
On the small island of Kinkazan, off of the eastern coast of Japan’s biggest Island Honshu, Japanese macaques compete for fibrous plant foods with sika deer. Of the six staple food plants on the island, the abundant Japanese barberry (Berberis thunbergii) and Japanese zelkova (Zelkova serrata) are unpalatable to the deer. A large part of the diet of Japanese macaques on the island is thus composed of these plants.
Animal Foods: eggs; insects
Plant Foods: leaves; roots and tubers; wood, bark, or stems; seeds, grains, and nuts; fruit; nectar; flowers
Other Foods: fungus
Primary Diet: herbivore (Folivore , Frugivore , Nectarivore ); omnivore