Originally Japanese macaques may have reached the islands of Japan by crossing a land bridge from Korea during the Middle Pleistocene, as long as 500,000 years ago. In 1972, 150 Japanese macaques were transported from Honshu to Laredo, Texas, where they were placed in an arid brush land habitat. This troop has survived quite well, growing to 470 individuals by 1989.
Japanese macaques are social primates and often vocalize within their troop and with related species. There are six groups of vocalizations used by Japanese macaques, including peaceful, defensive, aggressive, and warning vocalizations, which signal their mood. Other vocalizations include those that occur during female estrus and during infancy. More than 50% of vocalizations are peaceful or soothing in nature. Japanese macaques also make body gestures and facial expressions. In captivity during certain threatening situations, they display different facial expressions, including ear-flattening, opening their mouth to display teeth, raising their eyebrows, and even erecting their ears. Subordinate individuals also grimace, lip-smack, display their hindquarters and practice gaze-avoidance. Display behaviors are also common in Japanese macaques, with several different postures such as kicking, shaking, and leaping. These expressions increase in frequency in males during mating season, but they do not increase in females.
Communication Channels: visual ; tactile ; acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
Japanese macaques are considered a species of least concern by the ICUN and threatened by the US Federal List. Although populations are stable, they do face threats from deforestation and hunting because they are agricultural pests. Yakushima Island in Japan was designated a Natural World Heritage Site in 1993. Although established to protect native species, tourism to the island has increased to mixed effect. There are approximately 100,000 Japanese macaques in the wild.
US Federal List: threatened
CITES: no special status
IUCN Red List of Threatened Species: least concern
Japanese macaques are considered to be a nuisance, and they are the third worst crop pest behind wild boar and deer. They are also easily habituated to humans and may not be easily scared away. Increased predation on crops and presence near humans may be due to the reduction of natural habitat because of logging. Japanese macaques also carry similiar diseases to humans.
Negative Impacts: injures humans (carries human disease); crop pest
Japanese macaques are highly studied for their unusual behavioral patterns. They also carry similar diseases to humans. They may also attract tourists, although they are easily habituated to humans. Some individuals have become habituated to humans in as little as week, while others took several years or more.
Positive Impacts: ecotourism ; research and education
Japanese macaques eat a variety of plants and insects and, because they eat fruit and seeds, act as seed dispersers. They have been observed crushing and eating seeds and are also considered seed predators. About 36% of seeds on average were recovered after passing through the gastrointestinal process in captive Japanese macaques. Although Japanese macaques compete with Sika deer for some plants on Kinkazan Island, they are also commensalists. When Japanese macaques climb to the tops of trees to forage for the most energy sufficient foods, they inadvertently knock down leaves, which Sika deer eat.
Ecosystem Impact: disperses seeds
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
Japanese macaques, Macaca fuscata, inhabit subtropical or subalpine deciduous, broadleaf, and evergreen forests. They are found on three southern main islands of Japan: Honshu, Shikoku, and Kyushu, as well as a few smaller islands. Japanese macaques also survive well outside of their natural range, as with one introduced population in Laredo, Texas.
Biogeographic Regions: nearctic (Introduced ); oriental (Native )
Japanese macaques inhabit subtropical and subalpine forests. In the northern part of their range, they inhabit cool temperate deciduous broadleaf forests. In this region, temperatures average 10.9 ˚C, and annual average rainfall totals 1500 mm. In the southern part of their native range, Japanese macaques live in evergreen broadleaf forests. In this region, temperature averages 20 ˚C, and annual average rainfall totals 3000 mm. Across their range, harsh winters are inevitable, and Japanese macaques tend to spend winter months at lower elevations. Although they have been spotted at elevations as high as 3180 m, during winter months they usually do not exceed elevations of 1800 m.
Range elevation: 3180 (high) m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: forest ; mountains
Aquatic Biomes: coastal
Wetlands: marsh
In the wild, the oldest known male Japanese macaque was 28 years of age. The oldest known female was 32 years of age.
Average lifespan
Status: wild: male 28 years; female 32 years.
Average lifespan
Sex: female
Status: captivity: 22.7 years.
Average lifespan
Sex: male
Status: captivity: 27.0 years.
Average lifespan
Status: captivity: 33.0 years.
Average lifespan
Sex: female
Status: captivity: 32.0 years.
Average lifespan
Status: wild: 30.0 years.
Japanese macaques range in color from shades of brown and gray to yellowish brown. They have a colorful face and posterior end that are pinkish red in color. Their fur is very thick, which, because they do not hibernate, helps them stay warm during harsh winters. They have a short stumpy tail. Japanese macaques express sexual dimorphism; males are generally taller and more massive than females. Males average 11.3 kg in weight and 57 cm in height. Females average 8.4 kg in weight and 52.3 cm in height. There also seems to be a correlation between the body weight of Japanese macaques and climate. Japanese macaques in southern areas generally weigh less than those in northern areas of higher elevations, where more snow is present during winter months. Provisioned Japanese macaques have a larger skull than non-provisioned macaques. The skull of provisioned Japanese macaques averages 134.4 mm in length for males and 118.1 mm for females. The skull of non-provisioned individuals are slightly reduced, averaging 129.5 mm in males and 115.8 mm in females.
Average mass: male 11.3 kg; female 8.4 kg.
Average length: male 57 cm; female 52.3 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Average mass: 8882.5 g.
Japanese macaques have a variety of predators, including avian birds such as mountain hawk-eagles. Feral dogs frequently attacked and killed Japanese macaques, though they are now rare as populations of dogs are now regulated by the Japanese government. Japanese wolves also preyed on this species, although this subspecies of wolves went extinct in the early 1900s. Raccoon dogs may also prey on Japanese macaques. The most lethal predator of Japanese macaques is humans. Because they are considered agricultural pests, more than 10,000 Japanese macaques have been killed since 1998. When a predator is spotted, Japanese macaques make a hollering vocalization to warm others in the group. Japanese macaques have also been observed hollering when Japanese giant flying squirrels glide above them. This may be out of fear, as they may look like other avian predators.
Known Predators:
Courtship is a very important part of reproduction in Japanese macaques. Japanese macaques spend on average 1.6 days with their potential mate during courtship. During this time, they feed, nest, and travel together. Females stay with higher ranking males longer than with lower ranking males. When high ranking males observe a low ranking male with a potential mate, they may try to disrupt their courtship. Copulation can occur arboreally or terrestrially. Females have two types of mating calls. The first is a squawk or squeak that is vocalized just before copulation. The second sounds like an atonal cackle and is vocalized after copulation. Japanese macaques are polygynandrous; males and females copulate with available individuals and have multiple partners during a breeding season.
Mating System: polygynandrous (promiscuous)
Female Japanese macaques reach sexual maturity around 3.5 years of age, while males reach sexual maturity around 4.5 years. Although males as young as 1.5 years of age have been observed mounting females, they do not successfully copulate until they are older. Breeding usually occurs between March and September. Gestation lasts an average of 171.7 days, although this is misleading; adding one standard deviation in either direction produces a range of 157 to 188.5 days with a 95% confidence level. When females are ready to give birth, they usually leave the troop and find a safe and private place. Japanese macaques generally have 1 offspring during a breeding season. Twins are rare and occur once in every 488 births. At birth, males weigh on average 539.7 g and females 548.8 g. Weaning may occur as early as 6 to 8 months in some Japanese macaques. In some special cases, however, mothers may continue to nurse their offspring for up to 2.5 years if they have no other intervening births. Female Japanese macaques can produce a perfectly viable infant up to 25 years of age, although this is usual. Fertility does not appear to be correlated with menopause.
Some female Japanese macaques have been observed carrying the body of their infant that was stillborn or otherwise killed, such as in an attack by raccoons or dogs. This behavior sometimes lasts for several days. Males have also been observed committing infanticide. This may reduce time before a female is able to reproduce again, giving the male an opportunity to reproduce.
Breeding interval: Japanese macaques can breed once a year.
Breeding season: Japanese macaques breed from September to April
Average number of offspring: 1.
Range gestation period: 5 to 6 minutes.
Range weaning age: 6 to 24 + months.
Average age at sexual or reproductive maturity (female): 3.5 years.
Average age at sexual or reproductive maturity (male): 4.5 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
Average birth mass: 496 g.
Average number of offspring: 1.5.
Average age at sexual or reproductive maturity (male)
Sex: male: 1369 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 1483 days.
Parental care is an important aspect of the growth of Japanese macaques, and infant mortality is high in this species. Mortality before 1 year of age is 28.4%. During the first 4 weeks of life, infants are carried near the abdomen of adults. Young are carried near the abdomen or on the dorsal side of adults until they are 1 year old. Female Japanese macaques groom their adult offspring more often than their juvenile offspring. This may occur during the time frame when offspring observe behavioral patterns of their mothers, learning multiple successful traits needed later in life. In some troops of Japanese macaques, male paternal parental care is also present. Occasionally males, even high-ranking males, have been observed grooming and protecting infants. Males also carry infants from time to time.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Male, Female); pre-hatching/birth (Provisioning: Male, Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female); post-independence association with parents; extended period of juvenile learning; inherits maternal/paternal territory; maternal position in the dominance hierarchy affects status of young
