The Japanese macaque is a terrestrial Old World monkey species native to Japan. They are also sometimes known as the snow monkey because they live in areas where snow covers the ground for months each year — no other non-human primate is more northern-living, nor lives in a colder climate. Individuals have brown-grey fur, red faces, and short tails. There are two subspecies. One which is found across northern and mainland Japan, and the other is restricted to one of the country’s southern islands. The two differ very slightly in size and appearance.
In Japan, the species is known as Nihonzaru to distinguish it from other primates, but the Japanese macaque is very familiar in Japan, so when Japanese people simply say saru, they usually have in mind the Japanese macaque.
Japanese Macaque Anatomy and Appearance
The Japanese Macaque has a stocky body with a naked, red face that is said to resemble that of a Human. Their thick, furry coat is usually grey or brown in colour, sometimes with a slightly mottled pattern, and grows thicker during the winter months to allow the Japanese Macaque to stay warm in freezing conditions. Like other Monkey species, the Japanese Macaque has opposable thumbs, allowing it to grasp and hold objects and is able to walk on just it’s hind legs when it has something in it’s hands. The Japanese Macaque also has large pouches in it’s cheeks, to allow the Japanese Macaque to store food whilst foraging. They have a relatively short tail for their body size (in the same way as other primarily ground-dwelling Monkeys), and males tend to be somewhat larger than their female counterparts.
Japanese Macaque Distribution and Habitat
The Japanese Macaque is found in four separate regions in Japan throughout a variety of habitats from subtropical jungles to hot mountain springs, in forested hills, across highlands and high up in the mountains. In the northern and central parts of Japan, Japanese Macaques have to contend with seasonal changes with temperatures ranging from -15 degrees Centigrade in the winter to more than 23 in the summer, where the vegetation primarily consists of deciduous trees and conifers. In their most southern range, on the island of Yaku-Shima, the Japanese Macaques live amongst tropical broad-leaf forests that are subjected to less seasonal change. In central Japan, the Japanese Macaques are found in the mountains, where they warm themselves in the hot springs that are heated by nearby volcanoes.
Japanese Macaque Behaviour and Lifestyle
Japanese Macaques live together in troops that are led by the alpha male and usually consist of between 20 and 30 individuals. The alpha male not only helps to sire young, but also decides where the troop should go, and protects it from both predators and other Japanese Macaque troops. Social rank is very important in Japanese Macaque society, and consist of both males and females, with the male’s rank often determined by his age. Offspring however, are also thought to inherit the rank of their mother with younger siblings often outranking their older brothers and sisters. Japanese Macaques are incredibly sociable animals, particularly the females who tend to remain in the same troop for their whole lives, and spend their time together, grooming and raising the troop’s young.
Japanese Macaque Reproduction and Life Cycles
Female Japanese Macaques tend to reach sexual maturity about a year earlier than males, at between the ages of four and five. She usually chooses her mate by his rank, and after a gestation period that lasts for up to 6 months, the female Japanese Macaque gives birth to a single infant. Baby Japanese Macaques are incredibly dependent on their mother and remain clinging to her for their first couple of years, meaning that mother and baby often have a very close bond. Once weaned, males often leave the troop and spend their lives travelling between others, while females generally remain in the same troop that they were born into. Japanese Macaques tend to live for a relatively long time, often reaching ages of 30 years old or more.
Japanese Macaque Diet and Prey
The Japanese Macaque is an omnivorous animal meaning that it forages for both plants and smaller animals in order to survive. Unlike a number of other Monkey species, Japanese Macaques are primarily ground-dwelling so the majority of their foraging is done on the ground. They mainly eat fruits, berries, seeds, young leaves and flowers which they pick from the surrounding vegetation before storing it in their cheek pouches, so that they can continue to gather more. They also supplement their diet with Crabs, Insects and Bird’s eggs particularly during the colder winter months. Japanese Macaque babies feed on their mother’s milk until they are able to begin eating more solid foods.
Japanese Macaque Predators and Threats
Due to their fairly large size and diverse habitat ranges, the Japanese Macaque has no real predators in their natural environment, perhaps with the exception of the occasional hungry Wolf or Feral Dog. Humans are the primarily threat to the Japanese Macaque as they are often killed by farmers when they approach livestock and crops. However, the only reason that these conflicts occur is that the Japanese Macaque is being pushed into smaller and smaller pockets of it’s native ranges, due to deforestation and growing Human settlements. During the colder winter months, Japanese Macaque individuals in the north are also known to sleep in the deciduous trees to protect them from being buried in large amounts of snow during the night.
Japanese Macaque Interesting Facts and Features
The females are actually very picky when choosing a mate, as they will not mate with a male Japanese Macaque that they have mated with in the past few years, to prevent interbreeding within the troop. Japanese Macaques, particularity in the north, have different home ranges for the changing seasons which lead to their wide variety in diet and different habitats. They are incredibly intelligent and adaptable animals and are known to pass new behaviours through the generations. In the mid 1900’s a female was seen entering a hot spring to gather dropped soy beans and today, whole troops can be seen resting in the steaming waters to keep themselves warm.
Japanese Macaque Relationship with Humans
Like many of the 22 Monkey species found across Japan, the Japanese Macaque is often loved and protected by the native people. However, growing Human settlements and land clearance for logging and agriculture has meant that Japanese Macaques have lost vast areas of their natural habitats, and often have to approach farmland in order to find better food supplies. It is estimated that, despite being a protected species in Japan today, around 5,000 Japanese Macaque individuals are killed every year by farmers who claim to be protecting their livestock and their crops. In the Nagano Mountains in central Japan though, the Japanese Macaques that bath in the hot springs, have become one of the country’s most desirable tourist attractions.
Japanese Macaque Conservation Status and Life Today
Today, the Japanese Macaque has been listed as a Threatened species by the IUCN, with the southern subspecies of Japanese Macaque actually listed as Endangered. This means that both have been subjected to loss of their natural habitats and population numbers have dropped throughout the country. It is estimated that there could be as few as 50,000 individuals remaining in Japan today, but numbers are still declining particularly seeing that they are often killed, as they are seen as pests by local people.
Japanese snow monkey distribution map worldwide