mountain gorilla

mountain gorilla
mountain gorilla
systematics
Superfamily : Humanoids (Hominoidea) family : Great Apes ( Hominidae ) subfamily : homininae genus : Gorillas ( Gorilla ) Type : Eastern gorilla ( Gorilla beringei ) subspecies : mountain gorilla
Scientific name
Gorilla beringei beringei
Matschie , 1903

Yawning mountain gorilla in Rwanda

The mountain gorilla ( Gorilla beringei beringei ) is a subspecies of the eastern gorilla in the primate family Hominidae . Of all the gorillas , it represents the most terrestrial and leaf-feeding population. Mountain gorillas inhabit two small areas of eastern Africa, the Virunga Volcanoes area and Bwindi Forest , with the Bwindi Forest population possibly accounting for one subspecies ("Bwindigorilla") to be distinguished from the mountain gorilla.

features

Mountain gorillas have the stocky build that is typical of gorillas. Standing in a normal upright position, they can reach a height of up to 1.75 meters; males can weigh up to 200 kilograms, twice as heavy as females. The fur of these animals is colored black, the characteristic gray coloring of older males (see silverback ) is limited to the back as with all eastern gorillas. Characteristic are the elongated face and the relatively wide chest. As with all gorillas, their eyes are brown and the iris has a black ring around its edge.

They differ from the eastern lowland gorillas , their closest relatives, in their shorter arms and long, silky fur, among other things. They are also slightly smaller than the eastern lowland gorilla. Another characteristic of mountain gorillas is that the big toe is less splayed and connected to the other toes with connective tissue, giving their foot a human-like impression.

distribution and habitat

Mountain gorillas only inhabit two small areas in eastern Africa. On the one hand they occur on the slopes of the Virunga volcanoes in the border area of ​​the Democratic Republic of the Congo , Rwanda and Uganda , on the other hand in the Bwindi National Park in southwestern Uganda (Bwindi gorillas). Their habitat is mountain forests between 2200 and 4000 meters above sea level.

way of life

Like all gorillas, mountain gorillas live in groups, with groups being larger than other gorilla populations and averaging 9 to 10 (according to other sources, an average of 16) animals. As a rule, these groups consist of one adult male, several females and their offspring. But there are also groups with several males, with one of them taking the dominant role. The largest known group in May 2011 was that of the silverback Pablo. It consisted of 48 members, among them 13 adult males (of which six were silverbacks).

A behavioral -biological study of conspicuous "chest thumping" in male mountain gorillas found evidence that this display behavior also conveys correct information about their body size. According to the researchers' observations, large males "drum" at lower frequencies than smaller males because of their physique, while no correlation between body size and duration, number and beat frequency could be demonstrated; nevertheless there are individual beat rhythms. The researchers concluded that male rivals could probably better assess their competitiveness against the “drummer” without open debate based on the sound of body size.

At 400 to 800 hectares, the home ranges are smaller than those of other gorillas. A pronounced territorial behavior is not known, several groups can search for food in the same place, but not at the same time - groups usually avoid contact with each other. The daily distances traveled depend on the size of the group, the availability of food and the amount of rainfall in the range. Groups of gorillas from the lowlands migrate less than groups from higher altitudes due to the higher availability of fruit.

Mountain gorillas are the most terrestrial of all gorilla populations and rarely climb trees. On the ground, like all African apes , they use knuckles to move . Like all gorillas, they are diurnal and build a nest of leaves and branches to rest at night. This process usually takes less than five minutes, and a nest is usually only used once.

According to observations, Bwind gorillas are more likely to climb trees and have larger home ranges.

nutrition

Female gorilla beringei beringei eating in Bwindi Impenetrable National Park in Uganda

Compared to other gorillas, mountain gorillas eat significantly less fruit. Leaves are the main component of their diet. The daily forays these animals make in search of food are very short, averaging 0.4 kilometers. On the one hand, this is due to the mostly abundant supply of leaves and, on the other hand, to the low nutritional value of this food, which the animals make up for with long periods of rest.

However, the population of the Bwindi forest is likely to feed on fruit to a greater extent.

reproduction

cub

Mountain gorillas do not have a fixed mating season and can reproduce all year round. After a gestation period of around 257 days, the female usually gives birth to a single cub – twins are rare. Young animals are nursed for 3 to 4 years and reach sexual maturity at 6 to 8 years (females) or 10 years (males). Due to their social structure, however, most animals do not reproduce until several years after they have reached sexual maturity. Usually, both males and females leave their natal group when they become adults.

The generation time for the eastern gorilla, i.e. not specifically for the mountain gorilla, is given as 18.2 years for females and 20.3 to 21.7 years for males.

mountain gorillas and humans

Mountain gorilla in Volcanoes National Park in Rwanda

Mountain gorillas were described by German zoologist Paul Matschie in 1903 after officer Friedrich Robert von Beringe found and shot two animals. In his honor, the animals were given the scientific name Gorilla beringei - they were initially listed as a separate species, only later were they combined with all gorilla populations into one species.

Mountain gorillas were the first gorillas whose lifestyle was explored through long-term field studies. The American George Schaller started it in 1959, and in 1967 Dian Fossey 's almost two decades of research began . Her life and her murder in 1985 became known to a wider public through the filming of Gorillas in the Mist . The Dian Fossey Gorilla Fund continues to this day. During the military conflicts that have been going on around the volcanoes since 1989, observations had to be temporarily suspended.

The increasing tourist development of the two habitats around the Virunga volcanoes and in the Bwindi Impenetrable National Park in Uganda - which is recognized as a UNESCO World Heritage Site - in connection with the use of park rangers and veterinarians ensures a reasonably good protection of the mountain gorillas from habitat destruction and poaching. Nevertheless, the survival of the species is by no means assured. Oil concessions exist in most of Virunga National Park , threatening the mountain gorilla. The British company SOCO is one of the companies that received concessions.

Gorilla tourism has become a growing source of income for affected countries. Up to ten thousand people go exploring in African forests every year. This development entails risks, such as the transmission of diseases from humans to animals or vice versa. So far, the monkeys seem to benefit from tourism. Great apes, which are regularly visited by tourist groups, can be treated by veterinarians and, if necessary, protected by rangers.

population

The population has been estimated at a few hundred animals since the 1950s; At the end of the 1980s, around 620 animals were counted. In 2010 the population had grown to almost 800 animals - in 2006 302 animals were found in the Bwindi Forest, and in 2010 480 individuals were counted in the Virunga National Park . The results of another census in Bwindi Forest, available since November 2012, showed a population of at least 400 animals, resulting in a total population of over 880. In May 2018, the Max Planck Institute for Evolutionary Anthropology announced another census that had taken place in 2015 and 2016; accordingly, the population at that time was a little over 1000 individuals, of which, according to empirical values ​​for gorillas, around 60%, i.e. 600 individuals, would have to be assumed to be sexually mature.

Mountain gorillas are the only gorilla subspecies with an increasing population. The IUCN listed them as " Critically Endangered" until 2018 due to the small population . Since then, mountain orillas have only been classified as "endangered " . In addition to habitat destruction, illegal hunting and pet trade, these animals are also at risk from human-borne diseases (particularly respiratory infections).

Mountain gorillas are not currently kept in zoos, so the preservation of the species can only be guaranteed by protecting the wild animals. However, three young animals that were confiscated from poachers and smugglers are cared for in the orphanage of the Senkwekwe Center in the Virunga National Park. The station is home to the world's only mountain gorillas under human care. Their release into the wild is currently not planned.

systematics

In the past, all gorilla populations were combined into a single species, but today two species are distinguished, the western and the eastern gorilla . The mountain gorilla is a subspecies of the eastern gorilla and is thus more closely related to the eastern lowland gorilla - the second subspecies - than it is to the western lowland gorilla .

The systematic status of the gorillas of the Bwindi forest (“Bwindigorillas”) has not yet been definitively clarified. Differences in morphology and lifestyle suggest that they may represent another subspecies distinct from the mountain gorilla. These results are disputed by other researchers, who consider the differences to be too small. So far, Bwindi gorillas have not been recognized as a subspecies, despite sometimes different reports.

literature

• Thomas Geissmann: Comparative Primatology . Springer, Berlin 2003, ISBN 3-540-43645-6
• Ronald M. Nowak: Walker's mammals of the world . 6th edition. Johns Hopkins University Press, Baltimore 1999, ISBN 0-8018-5789-9 (English).
• DE Wilson & DM Reeder: Mammal Species of the World . Johns Hopkins University Press, 2005, ISBN 0-8018-8221-4

web links

Commons : Mountain gorilla ( Gorilla beringei beringei )  - Collection of images, videos and audio files

Wiktionary: Berggorilla  – Explanations of meaning, word origin, synonyms, translations

• Gorilla beringei ssp. beringei inthe IUCN Red List of Threatened Species . Retrieved September 22, 2009.
• Gorilla gorilla. In: Animal Info. March 2, 2005, archived from the original on November 11, 2018 ; retrieved 11 May 2019 (English, lifestyle information and population counts). 
• KA Cawthon Lang: Primate Factsheets: Gorilla (Gorilla) Taxonomy, Morphology, & Ecology. In: Primate InfoNet . October 4, 2005, accessed May 11, 2019 (English). 

itemizations

1. ↑ Geissmann (2003), p. 297
2. ↑ Nowak (1999), p. 621
3. ↑ The Dian Fossey Gorilla Fund International ( Memento of 15 January 2013 at the Internet Archive ).
4. ↑ Edward Wright et al.: Chest beats as an honest signal of body size in male mountain gorillas (Gorilla beringei beringei). In: Scientific Reports. Volume 11, item no. 6879, 2021, doi:10.1038/s41598-021-86261-8 .
   Male gorillas don't bluff. Chest drums honestly signals height. On: idw-online.de from April 8, 2021.
5. ↑ Jessica Ganas, Martha M. Robbins: Ranging behavior of the mountain gorillas (Gorilla beringei beringei) in Bwindi Impenetrable National Park, Uganda: a test of the ecological constraints mode. In: Behavioral Ecology and Sociobiology. Volume 58, 2005, pp. 277–288, doi:10.1007/s00265-005-0920-z , full text (PDF)
6. ↑ The Bwindi-Impenetrable Great Ape Project.
7. ↑ Dietary Variability of Mountain Gorillas in Bwindi Impenetrable National Park, Uganda (International Journal of Primatology, Vol. 25, No. 5, October 2004) ( Memento of December 17, 2013 at the Internet Archive )
8. ↑ ^{a b} Gorilla beringei ssp. beringei (mountain gorilla). iucnredlist.org, 2020, accessed 12 March 2021 (English). 
9. ↑ Homepage ( Memento of 12 June 2010 at the Internet Archive )
10. ↑ ^{a b} John Vidal: Congo's rare mountain gorillas could become victims of oil exploration . In: The Guardian . 1 August 2013, ISSN  0261-3077 ( theguardian.com [accessed 9 November 2019]).
11. ↑ Mountain Gorilla Tourism, In D+Z, Jg.56.2015:5
12. ↑ Linda Geddes: DNA tests reveal gorillas in dire straits. New Scientist of January 24, 2009, p. 13; see also: Katerina Guschanski et al.: Counting elusive animals: Comparing field and genetic census of the entire mountain gorilla population of Bwindi Impenetrable National Park, Uganda. Biological Conservation, Vol. 142, Issue 2, February 2009, pp. 290-300, doi : 10.1016/j.biocon.2008.10.024
13. ↑ Archived copy ( memento of the original from December 26, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 
14. ↑ News_121113_Bwindi-gorilla-census-shows-large-increase - The Dian Fossey Gorilla Fund International ( Memento of November 30, 2012 at the Internet Archive )
15. ↑ Archive link ( Memento of 2 December 2012 at the Internet Archive )
16. ↑ Number of wild mountain gorillas exceeds 1,000. Retrieved from eurekalert.org on May 31, 2018
17. ↑ Fatal Colds. In: wissenschaft.de. 7 July 2005, retrieved 7 September 2019 (Respiratory diseases brought by tourists kill mountain gorillas). 
18. ↑ Mountain Gorilla Deaths Linked to Human Virus - News Watch
19. ↑ Archived copy ( memento of the original from December 1, 2017 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 
20. ↑ Archived copy ( memento of the original from January 15, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 
21. ↑ EE Sarmiento, TM Butynski, & J. Kalina: Gorillas of Bwindi-Impenetrable Forest and the Virunga volcanoes: Taxonomic implications of morphological and ecological differences. In: American Journal of Primatology, 40 (1996); pp. 1-21.
22. ↑ eg CR Stanford: The subspecies concept in primatology: The case of mountain gorillas. Primates, 42(4) (2001); pp. 309-318.