Eastern gorilla

Last updated

Eastern gorilla [1]
Temporal range: Pleistocene to recent
Male Gorilla (181091305).jpg
Male
DSC 0310 1web.jpg
Female with infant
Both are mountain gorillas, photographed in Bwindi Impenetrable Forest
CITES Appendix I (CITES) [3]
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Suborder: Haplorhini
Infraorder: Simiiformes
Family: Hominidae
Subfamily: Homininae
Genus: Gorilla
Species:
G. beringei
Binomial name
Gorilla beringei
Matschie, 1903
Subspecies

G. b. beringei
G. b. graueri

Eastern gorilla
Eastern gorilla range
  Extant (resident)
  Possibly extant (resident)

The eastern gorilla (Gorilla beringei) is a critically endangered species of the genus Gorilla and the largest living primate. At present, the species is subdivided into two subspecies. There are 6,800 eastern lowland gorillas or Grauer's gorillas (G. b. graueri) [4] and 1,000 mountain gorillas (G. b. beringei). [5] Illegal hunting threatens the species. [6] [7]

Contents

Taxonomy and phylogeny

Mountain gorilla and eastern lowland gorilla G. b. beringei & G. b. graueri.jpg
Mountain gorilla and eastern lowland gorilla

There are two recognised subspecies of eastern gorilla: the mountain gorilla (Gorilla beringei beringei) of the volcanic slopes of Rwanda, Uganda and eastern Democratic Republic of Congo; and the eastern lowland gorilla or Grauer's gorilla (Gorilla beringei graueri) in eastern Democratic Republic of Congo.

The eastern lowland gorillas and mountain gorillas 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. [8] The two eastern subspecies are now classified as G. beringei.

Description

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 hair on the saddle of the back becomes white, much like the gray hair of elderly people. This is why the older males are called silverbacks. Grauer's gorilla has a shorter, thicker, deep black fur, while the mountain gorilla has a more bluish color. The mountain gorilla is slightly smaller and lighter than Grauer's gorilla, but still larger and heavier than the western lowland gorilla and the Cross River gorilla.[ citation needed ] Males are much larger than females. A full-grown male eastern gorilla typically weighs 140–205.5 kg (309–453 lb) and stands 1.7 m (5.6 ft) upright and a female typically weighs 90–100 kg (200–220 lb) and stands 1.5 m (4.9 ft) tall. [9] [10] The tallest silverback recorded was a 1.95-metre (6.4 ft) individual shot in Alimbongo, northern Kivu in May 1938. [11] The heaviest gorilla recorded was a 1.83-metre (6.0 ft) silverback shot in Ambam, Cameroon, which weighed 267 kilograms (589 lb), [11] although the latter area is within the range of the western gorilla, far outside that of the eastern gorilla.

Distribution and ecology

Mountain gorillas are restricted to the mountain rainforest and subalpine forest of eastern Democratic Republic of the Congo (DRC), southwestern Uganda and Rwanda. Grauer's gorilla occur across the forests of the Albertine Rift in eastern DRC.

Eastern gorillas are herbivorous, with a heavily foliage based diet, due to lack of available fruit in their habitats. They have smaller home ranges than western gorillas as foliage is more abundant than fruit. They are diurnal but the majority of foraging occurs in the morning and late afternoon. At night, they build nests by folding over vegetation, usually on the ground.

Behavior

Eastern gorillas live in stable, cohesive family groups, led by a dominant silverback male. Eastern gorillas tend to have larger group sizes than their western relatives, numbering up to 35 individuals. There is no distinct breeding season and females give birth only once every 3–4 years due to the long period of parental care and a gestation period of 8.5 months. Newborn gorillas have greyish-pink skin and can crawl after 9 weeks; they are not fully weaned until 3.5 years. Males defend their females and offspring using their large size in intimidating displays involving charging and chest-beating.

Conservation status

The eastern gorilla has become increasingly endangered since the 1990s, and the species was listed as critically endangered in September 2016 as its population continued to decrease. Primary threats to the eastern gorilla include habitat destruction for residential, commercial, and agricultural purposes, habitat fragmentation caused by transportation corridors and resource extraction, as well as disease. [2] Between 1996 and 2016, the eastern gorilla lost more than 70 percent of its population, and by 2016 the total population was estimated to be less than 6,000. [7] An exception to this declining trend is the mountain gorilla. According to the most recent estimates, there are approximately 1,004 mountain gorillas, and their numbers continue to grow. [12]

In some national parks, viewing mountain gorillas is a popular tourist attraction. These national parks include Volcanoes National Park in Rwanda, Virunga National Park in the Democratic Republic of the Congo, and Mgahinga Gorilla National Park and Bwindi Impenetrable National Park in Uganda. While ecotourism can benefit gorilla populations by generating revenue for conservation efforts, [13] there is concern that increased exposure to humans will place gorillas at greater risk of contracting zoonotic diseases. [14] Studies have shown that habituated eastern gorillas, that is, those that leave protected areas to forage in surrounding communities, have higher diseases rates than their unhabituated counterparts, with nearby humans and livestock as the likely sources of transmission. [15]

Unlike the western gorilla, there are few eastern gorillas in zoos. The Antwerp Zoo is the only zoo outside the native range of the species that has eastern gorillas. Outside the native range, the mountain gorilla is not held in captivity at all. [16] Small groups consisting of animals confiscated from poachers are kept in the Democratic Republic of Congo: Grauer's gorillas at the Gorilla Rehabilitation and Conservation Education (GRACE) center in Tayna Nature Reserve  [ fr ], [17] and mountain gorillas at the Senkwekwe Center in Virunga National Park. [18]

Related Research Articles

<span class="mw-page-title-main">Gorilla</span> Genus of large African apes

Gorillas are herbivorous, predominantly ground-dwelling great apes that inhabit the tropical forests of equatorial Africa. The genus Gorilla is divided into two species: the eastern gorilla and the western gorilla, and either four or five subspecies. The DNA of gorillas is highly similar to that of humans, from 95 to 99% depending on what is included, and they are the next closest living relatives to humans after chimpanzees and bonobos.

<span class="mw-page-title-main">Virunga Mountains</span> Chain of volcanoes in East Africa

The Virunga Mountains are a chain of volcanoes in East Africa, in the area where Rwanda, the Democratic Republic of the Congo (DRC), and Uganda meet. The mountain range is a branch of the Albertine Rift Mountains, which border the western branch of the East African Rift. They are located between Lake Edward and Lake Kivu. The name "Virunga" is an English version of the Kinyarwanda word ibirunga, which means "volcanoes".

<span class="mw-page-title-main">Mountain gorilla</span> Subspecies of the eastern gorilla

The mountain gorilla is one of the two subspecies of the eastern gorilla. It is listed as endangered by the IUCN as of 2018.

<span class="mw-page-title-main">Volcanoes National Park</span> National park in Rwanda

Volcanoes National Park is a national park in northwestern Rwanda. It covers 160 km2 (62 sq mi) of rainforest and encompasses five of the eight volcanoes in the Virunga Mountains, namely Karisimbi, Bisoke, Muhabura, Gahinga and Sabyinyo. It borders Virunga National Park in the Democratic Republic of Congo and Mgahinga Gorilla National Park in Uganda. It is home to the mountain gorilla and the golden monkey, and was the base for the primatologist Dian Fossey.

<span class="mw-page-title-main">Virunga National Park</span> National park in the Democratic Republic of the Congo

Virunga National Park is a national park in the Albertine Rift Valley in the eastern part of the Democratic Republic of the Congo. It was created in 1925. In elevation, it ranges from 680 m (2,230 ft) in the Semliki River valley to 5,109 m (16,762 ft) in the Rwenzori Mountains. From north to south it extends approximately 300 km (190 mi), largely along the international borders with Uganda and Rwanda in the east. It covers an area of 8,090 km2 (3,120 sq mi).

<span class="mw-page-title-main">Western lowland gorilla</span> Subspecies of ape

The western lowland gorilla is one of two Critically Endangered subspecies of the western gorilla that lives in montane, primary and secondary forest and lowland swampland in central Africa in Angola, Cameroon, Central African Republic, Republic of the Congo, Democratic Republic of the Congo, Equatorial Guinea and Gabon. It is the nominate subspecies of the western gorilla, and the smallest of the four gorilla subspecies.

<span class="mw-page-title-main">Eastern lowland gorilla</span> Subspecies of ape

The eastern lowland gorilla or Grauer's gorilla is a Critically Endangered subspecies of eastern gorilla endemic to the mountainous forests of eastern Democratic Republic of the Congo. Important populations of this gorilla live in the Kahuzi-Biega and Maiko National Parks and their adjacent forests, the Tayna Gorilla Reserve, the Usala forest and on the Itombwe Massif.

<span class="mw-page-title-main">Mgahinga Gorilla National Park</span> National Park in Uganda

Mgahinga Gorilla National Park is a national park in southwestern Uganda. It was created in 1991 and covers an area of 33.9 km2 (13.1 sq mi).

<span class="mw-page-title-main">Western gorilla</span> Species of ape

The western gorilla is a great ape found in Africa, one of two species of the hominid genus Gorilla. Large and robust with males weighing around 168 kilograms (370 lb), the hair is significantly lighter in color than that of the eastern gorilla,, and geographically isolated from them in a region at the midwest of the African continent. It is the second largest living primate after the eastern gorilla. Two subspecies are recognised for the western lowland gorilla is found in most of West Africa while the Cross River gorilla is limited to a smaller range in the north at the border of Cameroon and Nigeria. Both subspecies are listed Critically Endangered.

<span class="mw-page-title-main">Albertine Rift montane forests</span> Ecoregion in east-central Africa

The Albertine Rift montane forests is a tropical moist broadleaf forest ecoregion in east-central Africa. The ecoregion covers the mountains of the northern Albertine Rift, and is home to distinct Afromontane forests with high biodiversity.

<span class="mw-page-title-main">Wildlife of the Democratic Republic of the Congo</span>

The wildlife of the Democratic Republic of the Congo includes its flora and fauna, comprising a large biodiversity in rainforests, seasonally flooded forests and grasslands.

Grauer's swamp warbler is a species of Old World warbler in the family Locustellidae. It is found in Burundi, Democratic Republic of the Congo, Rwanda, and Uganda. Its natural habitats are freshwater lakes and freshwater marshes. It is threatened by habitat loss.

Phrynobatrachus graueri is a species of frog in the family Phrynobatrachidae. It is found in eastern Democratic Republic of the Congo, Rwanda, Uganda, and western Kenya. The specific name graueri honours Rudolf Grauer, Austrian explorer and zoologist who collected the holotype. Common names Rugege river frog and Grauer's puddle frog have been coined for it.

Grauer's cuckooshrike is a little known species of bird in the family Campephagidae. It is endemic to the Democratic Republic of the Congo. It is found in mid-elevation montane forests, where it can be locally common. Similar to other species endemic to the eastern Democratic Republic of the Congo, it is rarely reported due to ongoing armed conflict in the Albertine Rift.

<span class="mw-page-title-main">Golden monkey</span> Subspecies of Old World monkey

The golden monkey is a subspecies of the blue monkey. It is an Old World monkey found in the Virunga volcanic mountains of Central Africa, including four national parks: Mgahinga, in south-west Uganda; Volcanoes, in north-west Rwanda; and Virunga and Kahuzi-Biéga, in the eastern Democratic Republic of Congo. It is restricted to highland forest, especially near bamboo.

iGorilla is a software application (app) that is designed for use with the internet and multimedia enabled smartphones iPhone or iPod Touch, which were created by Apple Inc. iGorilla is the first app to be dedicated to the protection of mountain gorillas and is evidence that organizations involved in wildlife conservation are using digital media technology to raise funds and awareness by communicating directly with people who are concerned about the planet’s biological heritage.

<span class="mw-page-title-main">Itombwe Mountains</span>

The Itombwe Mountains are a range of mountains in the South Kivu province of the Democratic Republic of the Congo (DRC). They run along the west shore of the northern part of Lake Tanganyika. They contain a vast area of contiguous montane forest and are home to a rich diversity of wildlife.

<span class="mw-page-title-main">Rwenzori–Virunga montane moorlands</span> Montane ecoregion in central Africa

The Ruwenzori-Virunga montane moorlands is a montane grasslands and shrublands ecoregion of the Rwenzori Mountains and Virunga Mountains in central Africa.

<span class="mw-page-title-main">Kahuzi-Biéga National Park</span> National park in the Democratic Republic of the Congo

The Kahuzi-Biega National Park is a protected area near Bukavu town in eastern Democratic Republic of the Congo. It is situated near the western bank of Lake Kivu and the Rwandan border. Established in 1970 by the Belgian photographer and conservationist Adrien Deschryver, the park is named after two dormant volcanoes, Mount Kahuzi and Mount Biega, which are within its limits. With an area of 6,000 square kilometres (2,300 sq mi), Kahuzi-Biega is one of the biggest national parks in the country. Set in both mountainous and lowland terrain, it is one of the last refuges of the rare species of Eastern lowland gorilla, an endangered category under the IUCN Red List. The park is a UNESCO World Heritage Site, inscribed in 1980 for its unique biodiversity of rainforest habitat and its eastern lowland gorillas. In 1997, it was listed on the List of World Heritage in Danger because of the political instability of the region, an influx of refugees, and increasing wildlife exploitation.

<span class="mw-page-title-main">Rudolf Grauer</span> Austrian explorer and zoologist

Rudolf Grauer was an Austrian explorer and zoologist.

References

  1. ↑ Groves, C. P. (2005). Wilson, D. E.; Reeder, D. M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. pp. 181–182. ISBN   0-801-88221-4. OCLC   62265494.
  2. 1 2 Plumptre, A. J.; Robbins, M. M. & Williamson, E. A. (2019). "Gorilla beringei". IUCN Red List of Threatened Species . 2019: e.T39994A115576640. doi: 10.2305/IUCN.UK.2019-1.RLTS.T39994A115576640.en . Retrieved 12 November 2021.
  3. ↑ "Appendices | CITES". cites.org. Retrieved 14 January 2022.
  4. ↑ Plumptre, Andrew J.; Kirkby, Andrew; Spira, Charlotte; Kivono, Jeannot; Mitamba, Guillain; Ngoy, Erasme; Nishuli, Radar; Strindberg, Samantha; Maisels, Fiona; Buckland, Steeves; Ormsby, Lucy; Kujirakwinja, Deo (2021). "Changes in Grauer's gorilla (Gorilla beringei graueri) and other primate populations in the Kahuzi-Biega National Park and Oku Community Reserve, the heart of Grauer's gorilla global range" (PDF). American Journal of Primatology. 83 (7): e23288. doi:10.1002/ajp.23288. PMID   34056732. S2CID   235257115.
  5. ↑ "The most recent surveys of Mountain Gorillas estimated that there are now at least 1,004 individuals – IUCN Red List". IUCN Red List of Threatened Species . 31 July 2018. 31 July 2018.
  6. ↑ "The Eastern Gorilla listed on Red List of Endangered Species by IUCN". CBSnews. AP. 4 September 2016. Retrieved 4 September 2016.
  7. 1 2 "Four out of six great apes one step away from extinction – IUCN Red List". 4 September 2016. Archived from the original on 8 September 2016. Retrieved 4 September 2016.
  8. ↑ Taylor, Andrea Beth; Goldsmith, Michele Lynn (2003). Gorilla biology: a multidisciplinary perspective. Cambridge University Press. p. 13. ISBN   978-0-521-79281-3.
  9. ↑ Williamson, E. A. and Butynski, T. M. (2013) Gorilla gorilla. In: Butynski, T.M. (Ed) The Mammals of Africa. Volume 6. Elsevier Press. ISBN   1-4081-2256-1.
  10. ↑ Burnie D and Wilson DE (Eds.), Animal: The Definitive Visual Guide to the World's Wildlife. DK Adult (2005), ISBN   0-7894-7764-5.
  11. 1 2 Wood, Gerald L. (1983) The Guinness Book of Animal Facts and Feats. Sterling Pub Co Inc. ISBN   978-0-85112-235-9
  12. ↑ Hickey, J. R.; Basabose, A.; Gilardi, K. V.; Greer, D.; Nampindo, S.; Robbins, M. M.; Stoinski, T. S. (2020). "Gorilla beringei ssp. beringei (amended version of 2018 assessment)". IUCN Red List of Threatened Species . 2020: e.T39999A176396749. doi: 10.2305/IUCN.UK.2020-3.RLTS.T39999A176396749.en . Retrieved 23 October 2022.
  13. ↑ Okello, M. M & Novelli, Marina (1 January 2014). "Tourism in the East African Community (EAC): Challenges, opportunities, and ways forward". Sage. 14: 53–66 – via SAGE journals.
  14. ↑ Shackley, Myra (1 January 1995). "The future of gorilla tourism in Rwanda". Journal of Sustainable Tourism. 3 (2): 61–72. doi:10.1080/09669589509510711. ISSN   0966-9582.
  15. ↑ Kalema-Zikusoka, Gladys; Rubanga, Stephen; Mutahunga, Birungi; Sadler, Ryan (2018). "Prevention of Cryptosporidium and GIARDIA at the Human/Gorilla/Livestock Interface". Frontiers in Public Health. 6: 364. doi: 10.3389/fpubh.2018.00364 . ISSN   2296-2565. PMC   6302101 . PMID   30619805.
  16. ↑ Fossey, Dian (2000). Gorillas in the Mist. Houghton Mifflin Books. ISBN   0-618-08360-X.
  17. ↑ The Dian Fossey Gorilla Fund. "The GRACE Center for Rescued Gorillas". Archived from the original on 19 July 2013. Retrieved 16 August 2013.
  18. ↑ "Senkwekwe Orphan Mountain Gorilla Center". Archived from the original on 1 December 2017. Retrieved 16 August 2013.
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