Life span: 28 years (M), 32 years (F)
Total population: approx. 100,000
Gestation: 171 days
Height: 570.1 mm (M), 522.8 mm (F)
Weight: 11.3 kg (M), 8.4 kg (F)
Species: M. fuscata
Subspecies: M. f. fuscata, M. f. yakui
Japanese macaque, Japanese monkey, Snow monkey; macaque japonais,
macaque à face rouge (French); japansk makak (Swedish); macaca japonesa (Spanish); Nihon zaru (Japanese) (for vernacular names see Fooden & Aimi 2005:77); M.
fuscata yakui: Yaku monkey; Yakushimazaru, Yakuzaru (Japanese).
Two subspecies of Japanese macaque have been described, Macaca fuscata fuscata and
Macaca fuscata yakui. M. f. fuscata is the mainland subspecies of the Japanese
macaque. M. f. yakui is restricted to the island of Yakushima at the southern
limit of Macaca fuscata distribution and is distinguishable from M. fuscata due to
differences in pelage and body size (Fooden & Aimi 2005).
Photo: Alisha Eisert
The fur of the Japanese macaque can vary among shades of brown from grey or yellow brown to
exclusively brown (Fooden & Aimi 2005). Japanese macaques have a pinkish face and posterior with a
short stump of a tail (Rowe 1996). There is a degree of
between male and female
Japanese macaques with the males weighing somewhat more than the females and on average having a
longer body length than the females. The average body weight of the Japanese monkey is 11.3 kg
(24.91 lb) (M) and 8.4 kg (18.52 lb) (F) (Fooden & Aimi 2005). In addition, there appears to be a
correlation between climate and body weight, as Japanese monkeys from northern colder areas weigh
more than those from warmer areas of Japan (Hamada et al. 1996). Average body length for males is
570.1 mm (22.44 in) and for females is 522.8 mm (20.58 in) (Fooden & Aimi 2005). The tail is short,
averaging 92.51 mm (3.64 in) in males and 79.08 mm (3.11 in) in females (Hamada et al. 1996).
Longevity for males has been confirmed as long as 28 years and into the 32nd year of life for females
(Fedigan 1991; Nakamichi et al. 1995; Fedigan & Pavelka 2001). Actual average lifespan, however, is
significantly shorter; with wild females living for an average of just 6.3 years (Takahata et al.
Japanese macaques are predominantly quadrupedal and can be
considered semi-terrestrial. Females spend more time in trees than males and males spend more time
on the ground than females. Leaping is seen in the Japanese macaque, but suspension from supports is
not common (Chatani 2003). Japanese macaques are excellent swimmers and are reportedly able to swim distances of over half a
kilometer (Mito 1980 cited in Fooden & Aimi 2005). This macaque's fur is a unique adaptation to
cold, as fur thickness increases as habitat temperature decreases and allows the monkey to cope with
winter temperatures as low as -20° C (-4° F) (Hori et al. 1977).
CURRENT RANGE MAPS (IUCN REDLIST):Macaca fuscata
The Japanese macaque is native to the islands of Japan. Of the four main Japanese islands, Hokkaido,
Honshu, Shikoku, and Kyushu, Japanese macaques are found on all but Hokkaido, the northernmost
(Fooden & Aimi 2005). Even though its range is restricted to the three southern main islands of
Japan, the species nevertheless represents the northernmost wild populations of non-human primates
in the world. The absolute northernmost Japanese macaque populations are found at the northern tip
of the island of Honshu on the Shimokita peninsula (Izawa & Nishida 1963; Uehara 1975). These
northern populations exhibit significant cold adaptation as northern Honshu can be snowbound for
up to a third of the year (Izawa & Nishida 1963). Japanese macaques also inhabit several smaller
islands near the coasts of Honshu, Shikoku, and Kyushu (Fooden & Aimi 2005).
The southernmost population of Japanese macaques is that on Yakushima Island off of the south coast
of Japan and has been assigned its own subspecies, M.f.yakui (Uehara 1975; Hanya 2004).
In February 1972, a complete group of Japanese macaques numbering 150 individuals was transplanted
from Arashiyama, near Kyoto on Honshu to Laredo, Texas where it was established in an arid brushland
habitat and grew, having reached 470 individuals by 1989 (Fedigan 1991). The total
population of Japanese macaques has been estimated to be 114,431 individuals and likely numbers
around 100,000 individuals in its natural habitat (Hashiba 1989; Fooden & Aimi 2005). The Japanese
macaque is rarely found in lowland areas owing to the high levels of human habitation in those areas
(Amagasa & Ito 1978 cited in Fooden & Aimi 2005). The Japanese macaque has been studied in the
wild longer than most primate species, having been observed in numerous habitats and locations
throughout Japan for over 50 years (Yamagiwa & Hill 1998). Since the 1950's, study of Japanese
macaques has been undertaken at Arashiyama, near Kyoto (Huffman 1991a). This long-term study site
has not only served to provide information as to the long-term changes within a Japanese macaque
population, but also to serve as the source of the introduced Arashiyama West troop in Texas which
has provided not only a study site for the Japanese macaque in north America, but a place to study
adaptations of the species to a new habitat (Fedigan 1991). Within their range, the distribution
of the Japanese macaque is expanding, at least partially as a result of the species losing their
fear of humans, coupled with demographic and economic shifts in the Japanese human population
(Watanabe & Muroyama 2005). This expansion may be misleading as to the status of the species
however, because within the range, the total population is significantly limited by the distribution
of the natural broadleaf forest that is available. In addition, the expansion of the range
distribution was found to be correlated with the reduction of forests (Hashiba 1989).
Due to variations in the latitude and altitude of the Japanese islands, the habitat of the Japanese
macaque varies greatly between the extremes of its distribution. Near the southern end of the
population distribution, habitats include sub-tropical forest and at the northernmost reaches,
sub-arctic forest is found in mountainous regions. Between these two extremes, both warm and cool
temperate forests are found (Uehara 1975). These types of forest include both the deciduous forests
of central and northern Japan and the broadleaf evergreen forests of the southwest of the islands.
As is expected in a variable range, there is a large spectrum of vegetation within the distribution
of the Japanese macaque (Suzuki 1965). The highest elevation at which the Japanese macaque has been
reported is 3180 m (10,433 ft) (Izumiyama pers. comm. cited in Fooden & Aimi 2005). Of the habitats
of the Japanese macaque, the two most important are the warm temperate evergreen broadleaf forest
and the cool temperate deciduous broadleaf forest (Fooden & Aimi 2005). In the northern
forests, leaves are absent from the trees for up to 5 months of the year (Suzuki 1965). Near the
northern end of the range in the cool temperate deciduous broadleaf forest on the island of
Kinkazan, annual rainfall averages 1500mm (59.06 in) with an average temperature of 11° C
(51.8° F). At the extreme southern end of the macaque range on the island of Yakushima in warm
temperate evergreen broadleaf forest, annual rainfall averages 3000mm (118.11 in) with an average
temperature of 20° C (68° F). During the winter in high altitude or latitude areas of the
Japanese macaque range, snow is often quite deep, having been recorded on the Shimokita peninsula
and in the Shiga Heights in central Honshu to be between 2-3 meters deep during the winter
(Izawa & Nishida 1963; Hori et al. 1977).
Photo: Frans de Waal
The omnivorous Japanese
macaque is not a picky eater and will eat a great variety of foods including over 213 species of
plant (Koganezawa 1975). Other main foods eaten include insects and soil (Koganezawa 1975). As
expected, variable types of foods are available in different habitats and in some cases food
availability is profoundly seasonal. In the south of the range in temperate evergreen broadleaf
forest of Yakushima island, fruit predominates in the diet. At this location, the macaques will
eat fungi, ferns, invertebrates, soil and other parts of plants, but the main foods were fruits,
mature leaves, and fallen seeds (Maruhashi 1980; Agetsuma & Nakagawa 1998). Seasonality of the diet
is seen on Yakushima, with a greater number of fruits being eaten in the summer and more herbs being
eaten in the winter (Hanya 2004). In the deciduous broadleaf forests habitat of the north where
food is scarce in the winter, the species must eat surplus high quality foods such as fruits and
nuts prior to winter to store enough fat to survive through the lean winter (Hanya et al. 2006).
This storage of fat is important because during snowbound winter months the only available foods
are dead and poor in nutrition, including leaves and bark (Tsuji et al. 2006). In the deciduous
broadleaf forest habitat on the northern island of Kinkazan, food items are mainly fallen seeds,
herbs, young leaves and fruits (Agetsuma & Nakagawa 1998). The Japanese macaque has been observed
digging up underground plant parts such as roots, eating soil, and consuming raw fish if other
preferred food items are not to be found (Koganezawa 1975; Watanabe 1989; Iguchi & Izawa 1990).
The average group size of the Japanese macaque is 41 individuals but they can range from 10 to as
large as 161 (Fooden & Aimi 2005). If provisioned, groups are typically larger than wild groups
and in an extreme example a provisioned group grew to over a thousand individuals (Sugiyama &
Ohsawa 1988; Fooden & Aimi 2005). The home range averages around 3.7 km² (1.43 mi²)
with habitat type (Fooden & Aimi 2005). Home range decreases with access to cultivated land, as
this provides concentrated food sources which the macaque troops can utilize (Izumiyama et al. 2003).
There is also pronounced seasonality of daily path length, even in the southern reaches of the
Japanese macaque range on Yakushima. At this location, the daily path decreased from an average of
2.0 km (1.24 mi) per day during August and September to 1.2 km (.75 mi) per day later in winter
(Maruhashi 1979 cited in Maruhashi 1981). In habitats further north during the winter, movement is
even further restricted, averaging only .577 km (.36mi) for females and .529km (.33 mi) for males
(Koganesawa 1986). As less food is available in the winter and more in the summer and fall, daily
travel seems to be directly influenced by food availability; with less food there less travel
Photo: Alisha Eisert
The Japanese macaque is
diurnal. Daily activities vary with the seasons as well as with habitat. In colder areas
during the summer and fall when food is abundant, discrete daily patterns of activity emerge with
little variation. In the winter and spring when less food is available, levels of activity fall
and vary significantly from day to day (Yotsumoto 1976). In the autumn to early winter, the daily
activities are characterized by three bouts of feeding separated by other activities. In the
winter, two to four periods of feeding are observed with conspicuously less daily activity.
Finally, in the spring and summer, there are two or three bouts of feeding per day (Yotsumoto 1976).
The macaques typically sleep in trees but they also sleep on the ground, often on flat rocks and
fallen trees or behind rocks or fallen trees (Wada & Tokida 1985 cited in Fooden & Aimi 2005;
Takahashi 1997). In the winter, Japanese macaques will huddle together on the ground for warmth in
sleeping groups which grow larger with lower temperatures (Takahashi 1997). In warmer areas of the
Japanese macaque range on the island of Yakushima, daily activities were highly variable but time is
spent on average, 20.9% inactive, 22.8% traveling, 23.5% feeding, 27.9% social grooming, 1.2%
self-grooming, and 3.7% other activities (Maruhashi 1981). In Shiga Heights in central Japan,
the macaques enter and remain in hot springs in the winter, probably to regulate their body
temperature behaviorally (Hori et al. 1977).
Japanese macaques are preyed upon by several species including feral dogs and Mountain Hawk Eagles
(Spizaetus nipalensis) (Miyamoto 1976 cited in Fooden & Aimi 2005; Iida 1999). In
addition, raccoon dogs (Nyctereutes procyonoides) may be a predator of the Japanese
macaques, especially infants (Iwamoto 1974). Japanese macaques are also killed in Japan when their
crop-raiding and interactions with humans become a problem. The annual kill surpassed 10,000
individuals annually in 1998 (Watanabe & Muroyama 2005). This is significant because this annual
kill represents around a tenth of the entire estimated population.
Content last modified: April 26, 2007
Written by Kurt Gron. Reviewed by Sarah Turner.
Cite this page as:
Gron KJ. 2007 April 26. Primate Factsheets: Japanese macaque (Macaca fuscata) Taxonomy, Morphology, & Ecology . <http://pin.primate.wisc.edu/factsheets/entry/Japanese_macaque>. Accessed 2013 May 25.