Northern white-cheeked crested gibbon

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Northern white-cheeked crested gibbon
Northern white-cheeked crested gibbon - female (left) and male (right)

Northern white-cheeked crested gibbon - female (left) and male (right)

Systematics
Partial order : Monkey (anthropoidea)
without rank: Old World Monkey (Catarrhini)
Superfamily : Human (Hominoidea)
Family : Gibbons (Hylobatidae)
Genre : Crested Gibbons ( Nomascus )
Type : Northern white-cheeked crested gibbon
Scientific name
Nomascus leucogenys
( Ogilby , 1840)

The Northern White-cheeked Gibbon ( Nomascus leucogenys ) is a primate of the family of gibbons (Hylobatidae). Formerly it was combined with the southern white-cheeked crested gibbon to form a kind of white-cheeked crested gibbon.

features

Northern white-cheeked crested gibbons reach a body length of up to 52 cm and a weight of up to 6 kg. Males and juveniles are black with white cheek panels that begin with a narrow strip under the chin and each extend to the ears. Adult females are pale yellow to orange-yellow in color with a black to brown vertex and a white ring around the face, which is sometimes incomplete. The hair is long (40 to 70 mm) and quite coarse. The hair on the head of the male is straightened and extended in the middle so that it forms a high head of hair.

distribution and habitat

Distribution map

Northern white-cheeked crested gibbons live in the extreme south of the Chinese province of Yunnan as well as in the northern regions of Vietnam and Laos . In the north the Black River (Sông à) and in the west the Mekong form the limit of their distribution area.

The habitat is high primary and old, tropical, evergreen or semi-evergreen secondary forests, but also mixed coniferous forests in higher elevations in Vietnam . The gibbon species can be found at altitudes of up to 1650 m, but still prefers lower elevations, but can through the Habitat destruction can almost only be found in areas over 700 m.

Way of life

a male (right) is lukewarm by a female (left)

The northern white-cheeked crested gibbon is a diurnal tree dweller. The activity begins shortly before dusk, usually with loud calls.

Very little is known about the behavior. Most of the information comes from a very small population in China, and details about the Laotian and Vietnamese populations are based on anecdotal captive and field observations. Still, it seems to match that of other gibbon species. The northern white-cheeked crested gibbon is territorial and lives in monogamous family groups consisting of a couple and their offspring. The average in Yunnan in China is three animals, in Vietnam, according to a report, three to five.

There are initial indications that the northern white-cheeked crested gibbon feeds less on fruits than the other gibbon species. Leaves (36%) and shoots (17%) make up the largest proportion of food. They also consume fruits (39%), flowers (4%) and insects (3%). Fruits are most commonly eaten in the rainy season because of their high availability. In the dry season they mainly feed on leaves and hike longer distances.

Reproduction

subadult Northern white-cheeked crested gibbon

Only limited information on reproduction in captivity and in the wild is available. The pregnancy is 200 to 212 days. There is no evidence of higher birth rates in different seasons. Infants have whitish-gray-brown fur that turns black at 6 to 18 months. The males keep this coloration, while the females only acquire the typical female coat when they reach sexual maturity, which occurs at the age of 6 to 8 years. In zoos, however, northern white-cheeked gibbons gave birth to cubs when they were 4 years old. The lifespan in the wild is unknown, in captivity the gibbons can reach an age of up to 45 years.

Hybrids between the southern yellow-cheeked gibbon and the northern white-cheeked gibbon are known. It is even believed that the southern white-cheeked crested gibbon is not a species in its own right, but the natural hybrid between the above species. Hybrids with the western black crested gibbon have also been detected. Male and subadult hybrids in particular were very similar to the northern white-cheeked crested gibbon and could hardly be distinguished from it by their coat color. The Twycross Zoo also had a hybrid with the Hainan gibbon in 1987 . Hybrids have even been reported with the white-handed gibbon ( Hylobates lar ).

threat

The northern white-cheeked crested gibbon is classified by the IUCN as "critically endangered" (threatened with extinction). It is protected in China, Vietnam and Laos and occurs in 16 nature reserves. Population numbers, even from individual locations, are missing. It is believed that Laos is home to most of the Northern White-cheeked Crested Gibbons, as the largest forests live in protected areas. The population in Vietnam is better documented and consists of fewer than 300 groups. The Pu Mat National Park is probably home to the largest population in Vietnam with around 130 groups. In some regions, however, the species is already extinct and further local extinctions are likely to follow. In China the population has dropped dramatically. Only 10 animals in three groups live in two reserves, with no chance of surviving for a long time, as there is a high risk of inbreeding due to the few specimens. Hunting as food, for traditional Asian medicine and the pet market combined with habitat loss or destruction is a major hit for the species. Clearing for firewood, lumber and freeing up space for settlements, roads and farmland from growing populations in Vietnam, Laos and China are also a major threat. However, there are still no plans to conserve and protect this species.

Individual evidence

  1. ↑ Helen Dooley, Debra Judge: Vocal responses of captive gibbon groups to a mate change in a pair of white-cheeked gibbons (Nomascus leucogenys). In: Folia Primatologica. 78, No. 4, 2007, pp. 228-239, doi: 10.1159 / 000102318 .
  2. ↑ International Zoo Yearbook. 1983, p. 317.
  3. ↑ Thomas Geissmann: A female black gibbon, Hylobates concolor subspecies, from northeastern Vietnam. In: International Journal of Primatology. 10, No. 5, 1989, pp. 455-476, doi: 10.1007 / BF02736371 ; P. 462.
    Colin P. Groves: Systematics and phylogeny of gibbons. In: Gibbon and Siamang. 1, 1972, pp. 1-89; P. 61.
  4. ↑ International Zoo Yearbook. 1989, p. 320.
  5. ↑ Hirohisa Hirai, Yuriko Hirai, Hiroshi Domae, Yoko Kirihara: A most distant intergeneric hybrid offspring (Larcon) of lesser apes, Nomascus leucogenys and Hylobates lar. In: Human Genetics. 122, No. 5, 2007, pp. 477-483, doi: 10.1007 / s00439-007-0425-0 .

literature

Web links

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