Psychology Wiki
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| color = pink
| name = Gorillas<ref name=MSW3>{{MSW3 Groves|pages=181-182}}</ref>
| image = Gorilla 019.jpg
| image_width = 200px
| image_caption = [[Western Lowland Gorilla]]<br>(''Gorilla gorilla gorilla'')
| regnum = [[Animal]]ia
| phylum = [[Chordate|Chordata]]
| classis = [[Mammal]]ia
| ordo = [[Primate]]s
| familia = [[Hominidae]]
| subfamilia = [[Homininae]]
| tribus = '''Gorillini'''
| genus = '''''Gorilla'''''
| genus_authority = [[Isidore Geoffroy Saint-Hilaire|I. Geoffroy]], 1852
| type_species = ''[[Western Gorilla|Troglodytes gorilla]]''
| type_species_authority = [[Thomas S. Savage|Savage]], 1847
| subdivision_ranks = [[Species]]
| subdivision =
''[[Western Gorilla|Gorilla gorilla]]''<br/>
''[[Eastern Gorilla|Gorilla beringei]]''
| range_map = Gorilla distribution4.png
| range_map_width = 200px
| range_map_caption = distribution of ''Gorilla''
The '''gorilla''', the largest of the living [[primate]]s, is a ground-dwelling [[herbivore]] that inhabits the [[forest]]s of [[Africa]]. Gorillas are divided into two species and (under debate as of [[2006]]) either four or five subspecies. Its [[DNA]] is [[Human evolutionary genetics|97%-98% identical to that of a human]],<ref>In a talk presented at the Annual Meeting of the American Anthropological Association on November 20, 1999, Jonathan Marks stated: "Humans, chimpanzees, and gorillas are within two percentage points of one another genetically." {{cite web | title=What It Really Means To Be 99% Chimpanzee | author=Jonathan Marks | url= | accessdate=2006-10-10}}</ref> and is the next closest living relative to [[human]]s after the [[chimpanzee]] and [[orangutan]].
The American physician and missionary [[Thomas S. Savage|Thomas Staughton Savage]] first described the [[Western Gorilla]] (he called it ''[[Troglodytes gorilla]]'') in 1847 from specimens obtained in [[Liberia]]. The name was derived from the Greek word ''Gorillai'' (a "tribe of hairy women") described by [[Hanno the Navigator]], a Carthaginian navigator and possible visitor (circa [[480 BC]]) to the area that later became [[Sierra Leone]].<ref>{{cite book | author = Müller, C. | title = Geographici Graeci Minores | year = 1855-61 | pages = 1.1-14: text and trans. Ed, J. Blomqvist (1979)}}</ref>
== Physical characteristics ==
[[image:Gorilla-hand.jpg|thumb|left|200px|Hand of a Gorilla at San Diego Zoo]]Gorillas move around by [[knuckle-walking]]. Adult males range in height from 165-175 cm (5 ft 5 in-5 ft 9 in), and in weight from 140-200 kg (310-440 lb). Adult females are often half the size of a silverback, averaging about 140 cm (4 ft 7 in) tall and 100 kg (220 lb). Occasionally, a silverback of over 183 cm (6 feet) and 225 kg (500 lb) have been recorded in the wild. However, obese gorillas in captivity have reached a weight of 270 kg (600 lb).<ref>{{cite web | title=Gorilla - The Columbia Encyclopedia, Sixth Edition | | url= | accessdate=2006-10-10 }}</ref> Gorillas have a facial structure which is described as [[Prognathism#Mandibular prognathism|prognathous]], that is, their [[mandible]] protrudes further out than the [[maxilla]].
[[Gestation]] is 8½ months. There are typically 3 to 4 years between births. Infants stay with their mothers for 3-4 years. Females mature at 10&ndash;12 years (earlier in captivity); males 11&ndash;13 years. Lifespan is between 30&ndash;50 years. The [[Philadelphia Zoo]]'s [[Massa (gorilla)|Massa]] set the longevity record of 54 years at the time of his death.<ref>{{cite web | title=Western Lowland Gorilla | | url= | accessdate=2006-10-05}} Massa died of an apparent stroke shortly after a celebrating his birthday with a special meal. [] </ref>
Gorillas are mainly [[Herbivore|vegetarian]], eating fruits, leaves, and shoots. Insects make up 1-2% of their diet. Due to their diet of plant life, gorillas often have bloated stomachs.{{fact}}
Almost all gorillas share the same [[blood type]] (B)<ref>{{cite web | title=Blood Type Facts | url= | | accessdate=2006-10-10}}</ref> and, like humans, have individual finger prints.<ref>{{cite web | title=Santa Barbara Zoo - Western Lowland Gorilla | url= | | accessdate=2006-10-10}}</ref>
Until recently there were considered to be three species of gorilla, The Western Lowland, The Eastern Lowland and Mountain Gorilla. There is now agreement that the gorilla is divided into two species of at least two subspecies each. More recently it has been claimed that a third subspecies exists in one of these groups.
[[image:bristol.zoo.western.lowland.gorilla.arp.jpg|thumb|right|250px|[[Western lowland gorilla]]]]
[[image:Sleepygirlgorilla.jpg|thumb|right|250px|Female Gorilla at NC Zoo]]
[[Primatology|Primatologists]] continue to explore the relationships between various gorilla populations.<ref name=Groves2002>{{cite journal | first = Colin | last = Groves | authorlink = Colin Groves | year = 2002 | url = | title = A history of gorilla taxonomy | journal = Gorilla Biology: A Multidisciplinary Perspective</i>, Andrea B. Taylor & Michele L. Goldsmith (editors) | publisher = Cambridge University Press | pages = pp. 15–34}}</ref> The species and subspecies listed here are the ones most scientists agree upon.<ref name=MSW3/>
* '''Genus ''Gorilla'' '''<ref name=MSW3/>
** [[Western Gorilla]] (''Gorilla gorilla'')
*** [[Western Lowland Gorilla]] (''Gorilla gorilla gorilla'')
*** [[Cross River Gorilla]] (''Gorilla gorilla diehli'')
** [[Eastern Gorilla]] (''Gorilla beringei'')
*** [[Mountain Gorilla]] (''Gorilla beringei beringei'')
*** [[Eastern Lowland Gorilla]] (''Gorilla beringei graueri'')
The proposed third subspecies of ''Gorilla beringei'', which has not yet received a full latin designation, is the [[Mountain Gorilla (Bwindi population)|Bwindi population]] of the Mountain Gorilla, sometimes called Bwindi Gorilla.
Both species of gorilla are [[endangered species|endangered]], and have been subject to intense [[poaching]] for a long time. Threats to gorilla survival include [[habitat destruction]] and the [[bushmeat]] trade. In 2004 a population of several hundred gorillas in the [[Odzala National Park]], [[Republic of Congo]] was essentially wiped out by the [[Ebola virus]].<ref>{{cite web | title = Gorillas infecting each other with Ebola | url = | accessdate = 2006-07-10 | date = [[2006-07-10]] | work =}}</ref>
== Behavior ==
[[Image:Male silverback Gorilla.JPG|right|thumbnail|250px|A silverback gorilla]]
A '''silverback''' is an adult male gorilla, typically more than 12 years of age and named for the distinctive patch of silver hair on his back. A silverback gorilla has large canines that come with maturity. Blackbacks are sexually mature males of up to 11 years of age.
Silverbacks are the strong, dominant troop leaders. Each typically leads a troop of 5 to 30 gorillas and is the center of the troop's attention, making all the decisions, mediating conflicts, determining the movements of the group, leading the others to feeding sites and taking responsibility for the safety and well-being of the troop.
[[Image:gorilla-kiktajm.png|thumb|left|Gorilla at the Cincinnati Zoo]]
Males will slowly begin to leave their original troop when they are about 11 years old, travelling alone or with a group of other males for 2&ndash;5 years before being able to attract females to form a new group and start breeding. While infant gorillas normally stay with their mother for 3&ndash;4 years, silverbacks will care for weaned young orphans, though never to the extent of carrying the little gorillas.
If challenged by a younger or even by an outsider male, a silverback will scream, beat his chest, break branches, bare his teeth, then charge forward. Sometimes a younger male in the group can take over leadership from an old male. If the leader is killed by disease, accident, fighting or poachers, the group will split up, as animals disperse to look for a new protective male. Very occasionally, a group might be taken over in its entirety by another male. There is a strong risk that the new male may kill the infants of the dead silverback.
* The first reference to gorillas was in the diary/history of [[Hanno the Navigator]], a Carthaginian prince and sailor. There was some debate amongst his men as to whether gorillas were a separate species or just a strange tribe of men.<ref name=Groves2002/>
* 19th Century: The first scientific writings about gorillas dates back to the 1847 ''Proceedings of the Boston Society of Natural History'', where ''Troglodytes gorilla'' is described, with a few other species following in the next couple of years.<ref name=Groves2002/>
* Early 20th Century: The next systematic study was not conducted until the 1920s, when [[Carl Akely]] of the [[American Museum of Natural History]] traveled to Africa to hunt for an animal to be shot and stuffed. On his first trip he was accompanied by his friends [[Mary Bradley]], a famous mystery writer, and her husband. After their trip, Mary Bradley wrote ''[[On the Gorilla Trail]]''. She later became an advocate for the conservation of gorillas and wrote several more books (mainly for children). In the late 1920s and early 1930s, [[Robert Yerkes]] and his wife Ava helped further the study of gorillas when they sent [[Harold Bigham]] to Africa. Yerkes also wrote a book in 1929 about the great apes.
* Mid 20th Century: After WWII, [[George Schaller]] was one of the first researchers to go into the field and study primates. In 1959, he conducted a systematic study of the Mountain Gorilla in the wild and published his work. Years later, at the behest of [[Louis Leakey]] and the ''[[National Geographic]]'', [[Dian Fossey]] conducted a much longer and more comprehensive study of the Mountain Gorilla. It was not until she published her work that many misconceptions and myths about gorillas were finally disproved, including the myth that gorillas are violent.
== Intelligence ==
Gorillas are closely related to humans and are considered highly intelligent. A few individuals in captivity, such as [[Koko (gorilla)|Koko]], have been taught a subset of [[sign language]] (see [[animal language]] for a discussion).
=== Natural tool use by all the "great apes" ===
[[Image:Gorrila tool use-Efi.jpg||thumb|200px|right|A female gorilla exhibiting tool use by using a tree trunk as a support whilst fishing.]]
The following observations were made by a team led by Thomas Breuer of the Wildlife Conservation Society in September 2005. Gorillas are now known to use [[tool]]s in the wild. A female gorilla in the [[Nouabalé-Ndoki National Park]] in the [[Republic of Congo]] was recorded using a stick as if to gauge the depth of water whilst crossing a [[swamp]]. A second female was seen using a tree stump as a bridge and also as a support whilst fishing in the swamp. This means that all of the [[great ape]]s are now known to use tools.<ref>{{cite journal | last = Breuer | first = T | coauthors = Ndoundou-Hockemba M, Fishlock V | title=First Observation of Tool Use in Wild Gorillas | journal=PLoS Biol | year=2005 | pages=e380 | volume=3 | issue=11 | id=PMID 16187795 {{doi|10.1371/journal.pbio.0030380}}}}</ref>
In September 2005, a two and a half year old gorilla in the Republic of Congo was discovered using rocks to smash open palm nuts inside a game sanctuary.<ref name=ns>{{cite web | url = |date = 2005-10-18 | title = A Tough Nut To Crack For Evolution | publisher = CBS News | accessdate = 2006-10-18}}</ref>. While this was the first such observation for a gorilla, over forty years previously [[chimpanzee]]s had been seen using tools in the wild, famously 'fishing' for termites. Other animals also use tools, e.g. sea [[otter]]s use rocks on their chests to break sea urchins. It is a common tale among native peoples that gorillas have used rocks and sticks to thwart predators, even rebuking large mammals.{{cite needed}} Great apes are endowed with a semi-precision grip, and certainly have been able to use both simple tools and even weapons, by improvising a club from a convenient fallen branch. With training, in 20th Century carnival and circus acts, chimpanzees have been taught to operate simple motorbikes.
==Gorillas in pop culture==
{{main|Gorillas in popular culture}}
Giant gorillas have been a recurring theme in film since the 1930s. Following their popularity in the 1930s and 40s, most notably in the films [[King Kong]], [[Tarzan]], and [[Mighty Joe Young]], gorillas came to be heavily featured in [[comic book]]s. Short contrived gorilla plots were often included so that they could appear on the cover to boost sales.
Gorilla suits are an eternally popular gag costume, appearing in large numbers of TV shows since the 1950s. A number of sports teams have a gorilla as a mascot usually personified by an actor in a gorilla suit.
<!--please make fictional-gorilla additions to the sub-article at the link noted here -->
==See also==
*[[List of apes]] &mdash; notable individual apes
== References ==
*Fossey, D. (1980) Gorillas in the Mist, Basingstoke: Macmillan.
*Patterson, F.G. (1978) The gestures of a gorilla: language acquisition in another pongid, Brain and Language 5: 72-97.
*Patterson, F.G. (1979) Conversations with a gorilla, National Geographic 154(4): 438-65.
*Schaller, G.B. (1963) The Mountain Gorilla, Chicago, Ill.: University of Chicago Press
== External links ==
{{3d commons|Gorilla}}
{{wikinews|Researchers: Wild gorillas seen using tools}}
*ARKive - [ images and movies of the western gorilla ''(Gorilla gorilla)'']
*ARKive - [ images and movies of the eastern gorilla ''(Gorilla beringei)'']
*[ Bagheera] An educational website about Earth's Endangered Animals.
*[ Gorilla Haven] - information about gorillas
*[ The Gorilla Foundation], home of Koko the gorilla famous for her sign language skills
*[ Primate Info Net ''Gorilla'' Factsheet] - taxonomy, ecology, behavior and conservation
*[ San Diego Zoo Gorilla Factsheet] - features a video and photos
*[ World Wildlife Fund: Gorillas] - conservation, facts and photos
*[ Mountain Gorilla] - and also a lot of facts about gorillas
*[ Gorillas at Prague Zoo] - hit reality-tv show (24/7) of live gorillas at the Prague Zoo
*[ Gorilla quick facts]
*[ The Dian Fossey Gorilla Fund International]
[[es:Gorilla gorilla]]
[[it:Gorilla gorilla]]
{{enWP| Gorilla}}
[[Category:Fauna of Africa]]
[[Category:Fauna of Africa]]

Revision as of 05:21, 15 August 2020