Everything about Gorilla totally explained
Gorillas, the largest of the living
primates, are ground-dwelling
herbivores that inhabit the
forests of
Africa. Gorillas are divided into two species and (still under debate as of 2008) either four or five subspecies. The
DNA of gorillas is
97%–98% identical to that of a human, and they're the next closest living relatives to
humans after the two
chimpanzee species.
Gorillas live in tropical or subtropical forests. Although their range covers a small percentage of Africa, gorillas cover a wide range of elevations. The Mountain Gorilla inhabits the
Albertine Rift montane
cloud forests of the
Virunga Volcanoes, ranging in altitude from 2225 to 4267 m (7300-14000 ft). Lowland Gorillas live in dense forests and lowland swamps and marshes as low as
sea level.
Etymology
The American physician and missionary
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.
Classification
Until recently there were considered to be three gorilla species: the Western Lowland Gorilla, the Eastern Lowland Gorilla and the Mountain Gorilla. There is now agreement that there are two species with two subspecies each. More recently it has been claimed that a third subspecies exists in one of the species.
Primatologists continue to explore the relationships between various gorilla populations. The species and subspecies listed here are the ones upon which most scientists agree. Gorillas have a facial structure which is described as
mandibular prognathism, that is, their
mandible protrudes farther out than the
maxilla.
The Eastern Gorilla is more darkly colored than the Western Gorilla, with the Mountain Gorilla being the darkest of all. The Mountain Gorilla also has the thickest hair. The Western Lowland Gorilla can be brown or grayish with a reddish forehead. In addition, gorillas that live in lowland forests are more slender and agile than the more bulky Mountain Gorilla. and, like humans, have individual finger prints.
Behavior
Group life
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 canine teeth that come with maturity. Black backs are sexually mature males of up to 11 years of age.
Silverbacks are the strong, dominant troop leaders. Each typically leads a troop (
group size ranges from 5 to 30) and is in 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. Younger males called
blackbacks may serve as backup protection.
Males will slowly begin to leave their original troop when they're about 11 years old, traveling alone or with a group of other males for 2–5 years before being able to attract females to form a new group and start breeding. While infant gorillas normally stay with their mother for 3–4 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 the 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.
Food and foraging
Gorillas are
herbivores, eating fruits, leaves, and shoots. Further they're classified as
foliovores. Much like other animals that feed on plants and shoots, they sometimes ingest small insects also. Gorilla spend most of the day eating. Their large
sagittal crest and long canines allow them to crush hard plants like
bamboo. Lowland gorillas feed mainly on fruit while Mountain gorillas feed mostly on herbs, stems and roots.
Reproduction and lifespan
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 10–12 years (earlier in captivity); males at 11–13 years. Lifespan is between 30–50 years. The
Dallas Zoo's Jenny is still alive at age 55.
Recently, gorillas have been observed engaging in face-to-face sex, a trait that was once considered unique to humans and the
Bonobo.
Intelligence
Gorillas are closely related to humans and are considered highly intelligent. A few individuals in captivity, such as
Koko, have been taught a subset of
sign language (see
animal language for a discussion).
Tool use
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
tools 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 apes are now known to use tools.
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.. While this was the first such observation for a gorilla, over forty years previously
chimpanzees had been seen using tools in the wild, famously 'fishing' for termites. It is a common tale among native peoples that gorillas have used rocks and sticks to thwart predators, even rebuking large mammals. 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 twentieth century carnival and circus acts, chimpanzees have been taught to operate simple motorbikes.
Studies
The word "gorilla" comes from the history of
Hanno the Navigator, a Carthaginian explorer on an expedition on the west African coast. They encountered "a savage people, the greater part of whom were women, whose body were hairy, and whom our interpreters called Gorillae" . The word was then later used as the species name, though it's unknown whether what these ancient Carthaginians encountered were truly gorillas, another species of ape or monkeys, or humans. .
The first systematic study wasn't conducted until the 1920s, when
Carl Akeley 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.
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 wasn't until she published her work that many misconceptions and myths about gorillas were finally disproved, including the myth that gorillas are violent.
Endangerment
Both species of gorilla are
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. A 2006 study published in Science concluded
that more than 5,000 gorillas may have died in recent outbreaks of the Ebola virus in central Africa. The researchers
indicated that in conjunction with commercial hunting of these apes creates "a recipe for rapid ecological
extinction". Conservation efforts include the
Great Ape Survival Project, a partnership between the
United Nations Environment Programme and the
United Nations Educational, Scientific and Cultural Organization, and also an international treaty, the
Agreement on the Conservation of Gorillas and Their Habitats, concluded under UNEP-administered
Convention on Migratory Species. The
Gorilla Agreement is the first legally-binding instrument exclusively targeting Gorilla conservation and comes into effect on
1 June 2008.
Cultural references
Since they came to the attention of western society in the 1860s, gorillas have been a recurring element of many aspects of popular culture and media. For example, gorillas have featured prominently in monstrous fantasy films such as
King Kong, and
pulp fiction such as the stories of
Tarzan and
Conan have featured gorillas as physical opponents to the titular protagonists.
Further Information
Get more info on 'Gorilla'.
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