Western lowland gorilla

The western lowland gorilla (Gorilla gorilla gorilla) is a subspecies of the western gorilla (Gorilla gorilla) that lives in montane, primary, and secondary forests and lowland swamps in central Africa in Angola, Cameroon, Central African Republic, Congo, Equatorial Guinea and Gabon. It is the gorilla usually found in zoos. Adult male Gorillas are prone to cardiomyopathy, a degenerative heart disease.

Physical description
The western lowland gorilla is the smallest subspecies of gorilla. A male standing erect can be 5 – tall and weigh 300 - 600 lb. According to the Guinness Book of World Records, the average male is 168 kg and stands upright at 163 cm. Females stand 5 ft tall and weigh half as much as males. According to the late John Aspinall, a silverback gorilla in his prime has the physical strength of 7–8 Olympic weight lifters but this claim is unverified.

Behavior
Western lowland gorilla groups travel within a home range averaging 3 - 18 sqmi. Gorillas do not display territorial behavior, and neighboring groups often overlap ranges. The group usually favours a certain area within the home range but seems to follow a seasonal pattern depending upon the availability of ripening fruits and, at some sites, localised large open clearings (swamps and "bais"). Gorillas normally travel 0.3 - 1.8 mi per day. Populations feeding on high-energy foods that vary spatially and seasonally tend to have greater day ranges than those feeding on lower-quality but more consistently available foods. Larger groups travel greater distances in order to obtain sufficient food. Human hunters and leopards can also influence the movement patterns.

Gorillas live in family groupings of one dominant male known as a silverback, five to seven adult females, children and adolescents, and possibly a few non-dominant males. Gorillas reproduce slowly because females do not begin reproducing until the age of nine or ten and usually only produce one baby approximately every five years.

Diet
The main diet of the western lowland gorilla is vegetation, including roots and shoots. It will also eat fruit and tree bark. It may also eat insects from time to time. The adult will eat around 18 kg of food per day.

Conservation
In the 1980s, a census of the gorilla populations in equatorial Africa was thought to be 100,000. Researchers later adjusted the figure to less than half because of poaching and diseases. Surveys conducted by the Wildlife Conservation Society in 2006 and 2007 found about 125,000 previously unreported gorillas have been living in the swamp forests of Lake Télé Community Reserve and in neighboring Marantaceae (dryland) forests in the Republic of the Congo. However, gorillas remain vulnerable to Ebola, deforestation, and poaching.

Zoos worldwide have a population of 550 western lowland gorillas and the Cincinnati Zoo leads the United States in western lowland gorilla births.

Genetics
The genome of a western lowland gorilla was sequenced in 2012.

HIV
Western lowland gorillas are believed to be one of the zoonotic origins of HIV/AIDS. The SIV or Simian immunodeficiency virus that infects them is similar to a certain strain of HIV-1.