Japanese macaques (Macaca fuscata) are diurnal primates native to Japan. Their habitat includes regions varying from tropical lowlands to sub alpine highlands. They feed primarily on fruits, leaves, stems, and bark, but they will eat a variety of other incidental foods as well.

The macaques live in multi-male, multi-female troops inhabiting large overlapping home ranges that vary seasonally according to food resources. They have a linear dominance hierarchy that includes both males and females, in which adult females' and juveniles' ranks are determined by the rank of their mothers. In the center of the troop are the alpha male, subleader males, adult females, and offspring. The alpha and subleader males are responsible for maintaining order in the troop. Adolescent, adult, and migratory males are restricted to the periphery of the troop.

Aggression does occur between Japanese macaques, especially in times of resource competition (for food, mates, or space). Macaques often form alliance networks by aiding one another in their agonistic encounters, often tending to aid those from their own kingroup.

Japanese macaques have a mating system based on hierarchical promiscuity. Both males and females mate with multiple partners in a single breeding season. There is a great deal of competition for females, and the dominant male usually claims reproductive priority. However, lower-ranking males are able to find mating opportunities, sometimes through "sneak copulations." Females have a large degree of choice in which male(s) she mates with. Females have an estrus cycle and 6 month gestation period, after which they give birth to single infants, usually only one per year.

Adolescent females, and to some extent adolescent males, help the mothers care for the new offspring. This allomothering helps the young females gain maternal experience, thus enhancing their potential reproductive fitness.

Male young emigrate from the troop at sexual maturity in order to prevent inbreeding, but female young remain in the troop and maintain strong social bonds with female members of their kingroup throughout their lives. All troop members maintain their social bonds by allogrooming.

Japanese macaques have also demonstrated a high capacity for social learning. Troops of macaques have learned helpful skills such as potato washing and separating wheat from the sand they find it in.

They have few natural predators but are greatly threatened by the growing human population and resulting deforestation. Though they are protected by the Japanese government, their numbers are declining. Thus, it is important to understand the social systems of Japanese macaques and other endangered animals in order to help preserve their species.