Japanese Macaque Fact File
The Japanese macaque is a medium sized monkey which has a coat which is variable in color from gray to brown. Their thick coat of fur protects them against the cold and can be seen on all areas of the body except the face and rump. The coat is lighter during summer.
On the face and rump bare skin can be seen which is red. This will turn a darker shade during the breeding season.
Their tail is short reaching a length of just 7-12cm (2.5-4in) long.
Japanese macaques are old world monkeys and as such lack a prehensile tail. They do have the ability to close their nostrils.
As with all macaques they have an opposable thumb which can be used to manipulate objects.
Males tend to be larger and heavier than the females. Their body measures between 47 and 72cm (18.5 and 28in) long with an average weight between 8 and 11kg (18-24lbs).
Japanese macaques are omnivorous. Their diet includes leaves, fruits, berries, seeds, roots, flowers, nectar small animals, fish, insects, shellfish and fungi. Plants form a majority of their diet with the animal matter supplementing this.
To obtain minerals they will eat soil.
In some populations they have been seen to wash their food. The purpose of this is unknown but one hypothesis is that it adds additional salt to their food.
Average 22-27 years
Record 32 years
— AD —
Asia is the native home of the Japanese macaque where they are exclusively found in Japan. Their range covers three main islands known as Honshu, Shikoku and Kyushu along with a few smaller islands. They have gone extinct on Tane island.
For a brief period in 1996 a colony of Japanese macaques lived semi-wild in an area of Texas.
Japanese macaques are the most northerly living non-human primates and can withstand temperatures as cold as -15 °C.
Japanese macaques make their home in deciduous and evergreen forest. They can be found from sup-tropical areas up to sub-alpine environments. The most famous populations live near hot springs.
Breeding takes place from September to April. During this time the male and female will travel together, feeding and nesting with one another. Higher ranking males will seek to disrupt the courtship of lower ranking males. Males and females may mate with multiple partners during the breeding season.
The female gives birth to a single infant after a 171 day gestation period. Twins do occur on rare occasions. From birth the young cling to their mother and are carried around by her until they are one year old.
Males are sometimes observed carrying and grooming infants.
Weaning occurs between six and eight months old. In some cases though mothers have been seen nursing an infant as old as 2.5 years.
In the event the infant is stillborn or is killed by a predator the female will often carry it for many days while she mourns. Over a quarter of young macaques pass away in their first year of life.
Females mature first at around 3.5 years old with males maturing after 4.5 years.
Japanese macaques are best known for their habit of sitting in hot springs which help to warm them up in their cold environment.
Their days are split between foraging, sunbathing, sleeping, huddling together and bathing at the hot springs.
Each troop has slight variations in their behavior. Behaviors have been seen to move between troops when animals are evicted and join another group and also to be passed down through the generations.
For most of their time they walk on four legs but if carrying an item they have been observed walking on two legs.
They are active by day.
Japanese macaques form troops led by an alpha male. The social bonds between females outrank this male though. In most troops the dominant individuals are allowed to eat first.
Members of a troop are often seen grooming one another and this is thought to reinforce social bonds. It also helps to keep them free of predators.
Troops often include between twenty and thirty individuals but have been observed reaching as high as 100 members.
Predators and Threats
Natural predators of the Japanese macaque include birds of prey such as the mountain hawk-eagle, feral dogs and racoon dogs. Feral dog populations are the subject of control measures by the government which has assisted them. Prior to their extinction the Japanese wolf was another predator of Japanese macaques.
Humans target them as they are seen as a pest of agricultural crops. This leads to the destruction of as many as 10,000 individuals each year.
Another threat is hybridizing with introduced macaques, namely the rhesus and Taiwanese macaques.
Japanese macaques are also known as snow monkeys.
These monkeys are important in Japanese culture, folklore and and art.
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