Japanese Macaque

## Description

The Japanese macaque is an Old World monkey species - the northernmost-living nonhuman primate. They are colloquially referred to as "snow monkeys" because some live in areas where snow covers the ground for months each year. They have long, thick fur, of a brown or grey color. The dense fur contrasts with their faces, which have naked skin, as do their rump, which is red in adults. The male is larger than the female. Macaques have long whiskers and a beard, and their tail is short. As with other monkey species, the macaque has opposable thumbs, enabling it to take hold of things. It walks on its hind legs when holding something in its hands.

## Distribution

Japanese macaques are found on three of the four main Japanese islands: Honshu, Shikoku, and Kyushu. They inhabit subtropical forests in the southern part of their range and subarctic forests in mountainous areas in the northern part of their range. They can be found in both warm and cool forests, such as the deciduous forests of central and northern Japan and the broadleaf evergreen forests in the southwest of the islands.

## Behavior

Japanese macaques live in groups of 20-30, led by the dominant male. Females stay in their birth group for life, but males leave the group before sexual maturity. Females spend more of their time in trees, while males spend most of their time on the ground. The dominant male has a role in siring young, deciding where the troop should go and protecting the troop from predators and other macaque troops. Japanese macaques feel at home both in trees and on the ground. Females spend more time in the trees and males spend more time on the ground. They are very good swimmers, being able to swim over half a kilometer, and are known to leap. During feeding or moving, Japanese macaques often emit "coos". These most likely serve to keep the troop together and strengthen social relations between females. Coos are also uttered before grooming along with "girney" calls. Japanese macaques also have alarm calls for alerting to danger, and threat calls heard during aggressive encounters.

## Diet

Japanese macaques are omnivores. Their diet includes smaller animals and plants, mainly fruits, berries, seeds, flowers, and young leaves. They also eat insects, crabs and bird's eggs during the winter months.

## Reproduction

Japanese macaques are polygynadrous (promiscuous) meaning that both the males and females have multiple partners during each breeding season, which lasts 4 to 5 months between September and April. Females usually choose a mate by his rank. Births occur between March and September, after a gestation period lasting 6 months. Females usually give birth on the ground and infants are born with dark-brown hair. They consume their first solid food at 5 to 6 weeks old and can forage independently from their mothers by 7 weeks. Females carry their infants on their bellies for their first 4 weeks. After this time, they carry infants on their backs, as well. Infants continue to be carried past a year. Full weaning usually occurs when infants are 18 months old.

## Population

### Threats

Japanese macaques face no major threats at the species level. However, around 10,000 macaques are killed by farmers every year, protecting their crops and livestock.

### Number

According to the IUCN Red list, the Japanese macaque is common, widespread, and increasing in recent years. The total population is estimated at 114,431 individuals.

### Ecological niche

Japanese macaques consume a variety of insects and plants and act as seed dispersers. They compete for some plants with Sika deer on Kinkazan Island, but when they climb trees to get the most energy-sufficient leaves, in the process they knock down leaves, which the Sika deer eat. Japanese macaque serves as important prey species for mountain hawk-eagles, Japanese wolves, and raccoon dogs.

## Fun Facts

Macaques are excellent swimmers.

In snowy areas Japanese macaques sleep up in deciduous trees to avoid snow falling on them.

Macaques make different sounds for different situations: warning, defense, mating, and fighting.

Young macaques play with stones, fight and swing in trees. When there is snow around, they will make snowballs, rolling them about until they become too large or break up.

They wash their food before eating it. Only humans and raccoons do the same.

One way Japanese macaques cope with the cold is to soak in volcanic hot springs, spending about 30 minutes per day in them. This practice was first observed about 40 years. A monkey had seen humans soaking in the hot springs, and passed the idea on to the troop.