Eastern Gorilla

Taxobox
name = Eastern GorillaMSW3 Groves|pages=181-182|id=12100788]
status = EN
trend = unknown
status_system = iucn3.1
status_ref = [IUCN2006|assessors=Butynski "et al"|year=2000|id=39994|title=Gorilla beringei|downloaded=09 May 2006 Database entry includes a brief justification of why this species is endangered and the criteria used ]


image_width = 250px
regnum = Animalia
phylum = Chordata
classis = Mammalia
ordo = Primates
familia = Hominidae
genus = "Gorilla"
species = "G. beringei"
binomial = "Gorilla beringei"
binomial_authority = Matschie, 1903
subdivision_ranks = Subspecies
subdivision = "G. b. beringei"
"G. b. graueri"

The Eastern Gorilla ("Gorilla beringei") is a species of the genus "Gorilla" and the largest living primate. At present, the species is subdivided into two subspecies. The Eastern Lowland Gorilla ("G. b. graueri") is the most populous, at about 16,000 individuals.cite web | accessdate = 2006-04-18 | title = Eastern Lowland Gorilla | publisher = World Wide Fund for Nature | url = http://www.panda.org/about_wwf/what_we_do/species/our_solutions/endangered_species/great_apes/gorillas/eastern_lowland_gorilla/index.cfm] The Mountain Gorilla ("G. b. beringei") has only about 700 individuals. In addition, scientists are considering elevating the Bwindi gorilla population (which numbers about half of the Mountain Gorilla population) to the rank of subspecies.

Physical characteristics

The Eastern Gorilla is a large hominid with a large head, broad chest, and long arms. It has a flat nose with large nostrils. The face, hands, feet and breast are bald. The fur is mainly black, but adult males have a silvery "saddle" on their back. When the gorilla gets older, the entire fur becomes grayish, much like the gray hair of elderly people. This is why the older males are sometimes called "Silverbacks". The Eastern Lowland Gorilla has a shorter, thicker, deep black fur, while the Mountain Gorilla has a more bluish color. Males are much larger than females. A full-grown adult male can weigh up to 220 kg. [cite book|author=Caldecott, Julian; Miles, Lera|title=World Atlas of Great Apes and Their Conservation|publisher=University of California Press|year=2005|id=ISBN 0-520-24633-0] The tallest silverback recorded was a 1.94 m (6.4 ft) individual shot in Alimbongo, northern Kivu in May 1938 and the heaviest was a 1.83 m (6 ft) silverback shot in Ambam, Cameroon which weighed about 266 kg (585 lb). [Wood, The Guinness Book of Animal Facts and Feats. Sterling Pub Co Inc (1983), ISBN 978-0851122359]

Distribution and habitat

The Eastern Gorilla occurs in the lowland and mountain rainforests and subalpine forests of eastern Congo-Kinshasa, southwestern Uganda and Rwanda, within the triangle between the Lualaba River, Lake Edward and Lake Tanganyika. The Eastern Gorilla prefers forests with a substrate of dense plant material.

The species lives in small family groups, containing up to 40 animals. A group is led by a dominant male, a silverback, a few related females and their offspring. The Eastern Gorilla is not territorial, and the area of a group of gorillas often overlaps with that of other groups.

The gorilla is diurnal and herbivorous; its diet consists mainly of fruit, leaves, and branches. Most of the time is spent by searching for food and resting.

Classification

There are at least two subspecies of the Eastern Gorilla: the Mountain Gorilla ("Gorilla beringei beringei") of the volcanic slopes of Rwanda, Uganda and eastern Congo-Kinshasa; and the Eastern Lowland Gorilla ("Gorilla beringei graueri") of the lowlands of eastern Congo and Uganda. A small population from the Bwindi Impenetrable Forest in southern Uganda and adjacent areas in Congo differs genetically from the other subspecies, and is therefore often considered as a separate, yet undescribed, subspecies.

The Eastern Lowland Gorilla and Mountain Gorilla were previously thought to be two of the three subspecies of one single species, the gorilla ("Gorilla gorilla"). However, genetic research has shown that the two eastern subspecies are far more closely related than the western subspecies: the Western Lowland Gorilla ("G. gorilla gorilla"), which justified the separate classification.Fact|date=December 2007 The two eastern subspecies are now classified as "G. beringei".

Relation to humans

The Eastern Gorilla is the most critically endangered of the two gorilla species. The hunt for bushmeat and the decline in suitable habitat as a result of intensifying forestry and the development of agriculture form the most important threats for the species. In some national parks, expeditions in search for Mountain Gorillas are a popular tourist attraction. This has both advantages (environmental awareness, financial benefit) and disadvantages (disturbance of natural behavior) for the conservation of the gorillas.Fact|date=September 2008

As opposed to the Western Lowland Gorilla, the Eastern Gorilla is seldom found in zoos. The Antwerp Zoo is probably the only Western zoo that has Eastern Lowland Gorillas (two older females). The Mountain Gorilla is not held in captivity at all. [cite book|last=Fossey|first=Dian|title=Gorillas in the Mist|publisher=Houghton Mifflin Books|year=2000|id=ISBN 0-618-08360-X]

References