Western Gorilla – Gorilla gorilla

Description

The western gorilla is the species with more individuals in the wild. There are two subspecies: the western lowland gorilla (Gorilla gorilla gorilla) and the Cross River gorilla (Gorilla gorilla diehli).

This species has large, burly individuals. The average male height is 1.55 meters, and females are on average 1.35 meters. Their weight is on average 80 kilos in females and 157 kg in males, estimation based on captive individuals. Their muzzle is short, with strong muscles in the jaw area.

A dark fur covers most of their body. Individuals of the species Gorilla gorilla show a clearer tone than their eastern relatives who can show brown or even slightly reddish coat.

Distribution and habitat

A few years ago, the western gorilla distribution was almost in an uninterrupted territory, but at present, there are small and isolated populations, and they have become extinct in the Democratic Republic of Congo. This species still resides in Nigeria, Equatorial Guinea, Angola, Cameroon, Central African Republic, Congo, and Gabon.

Each subspecies has it own range of distribution. The western lowland gorilla (Gorilla gorilla gorilla) lives in areas of Cameroon, Congo, Gabon, Equatorial Guinea and the Central African Republic. It inhabits south of the Sanaga River, the estuary of the Congo River continuing east until the Oubangi River. The Cross River gorilla (Gorilla gorilla diehli) has a limited distribution, as it only inhabits a small area between Nigeria and Cameroon.

They dwell mainly lowland tropical forests, swamp forests, and primary and secondary forests.

Feeding habits.

Every day these gorillas travel between 1 and 4 kilometers to find fruit trees.

Gorillas are mainly herbivores. Western gorillas feed on leaves, buds, and especially fruit. The availability of these varies throughout the year, so its consumption may also change. They eat large quantities of fruits of the genus Dialium, Tetrapleura, Chrysophyllum, and Landolphia. Occasionally they catch ants, termites, worms, grubs, and caterpillars.

When the fruit is scarce, they are forced to eat leaves, woody vegetation, bark and low-quality herbs, such as those that belong to the genders Aframomum and palisota.

Information about western gorilla.

Western gorilla (Gorilla gorilla).

Behavior

The western gorilla lives in groups of 2-20 individuals, with a leader, which is a “silverback” male with the responsibility to defend the females in the group and their offspring. Both genders leave their born troop at adulthood and move to other groups to avoid crossbreeding and leadership confrontations.

Their life is peaceful, with few aggressive incidents. In the case of danger, the silverback male makes a threatening display for intimidating the intruder; therefore he stands on two legs, makes loud vocalizations and beats his chest with both hands.

In cases of danger, the silverback male makes loud vocalizations and beats his chest with both hands.

Group members communicate with each other through alarm calls, facial gestures, movements, postures, and touching. They are diurnal and relatively sedentary because they do not perform migrations although they travel together for months and years in search of food. Therefore, they are not territorial.

Reproduction

It is a polygamous species, like all gorillas. Females can start having offspring when they are 8 or 9 years old, although the average sexual maturity age is ten years.

The dominant male or leader is the only one that can mate with the females of their group, and this can happen during any time of the year since there is no specific breeding season. The gestation period is about 8.5 months, and usually, only one infant is born weighing roughly 2 kg.

Mothers nurse their young for 3 or 4 years, and they transport and take care of them. The males hardly interact with the infants. Many babies die; if the female delivers twins she allows one to die because it is hard to take care and transport both.

Their life expectancy in the wild is up to 40 years.

Threats and conservation

They are victims of poaching, diseases and habitat loss.

This species appears in the Red List of the International Union for Conservation of Nature as a “Critically Endangered Species”. Regardless this, it is a species victim of poaching, infectious diseases and habitat loss. The low birth rates of the species worsen the problem, as the number of individuals does not increase quickly enough.

Gorilla hunting is prohibited internationally. The Convention on International Trade in Endangered Species (CITES) includes this species in Appendix I, considering them in great danger of extinction. However, the problem is that the conservation laws in some of the African countries where they live are not enforced as they should.

 

Western gorilla Infographic!

Western_Gorilla copia

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Sources:

http://library.sandiegozoo.org/factsheets/gorilla/gorilla.htm

http://www.iucnredlist.org/details/9404/0

http://animaldiversity.org/accounts/Gorilla_gorilla/

https://en.wikipedia.org/wiki/Western_gorilla

http://www.arkive.org/western-gorilla/gorilla-gorilla/

http://wwf.panda.org/what_we_do/endangered_species/great_apes/gorillas/western_lowland_gorilla/index.cfm

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