A female western lowland gorilla, drawn from a photograph by Katharina Scafler
The western lowland gorilla is smallest of two subspecies of western gorilla that lives in the forests and lowland swamps of central Africa. Nevertheless it is still a primate of exceptional size and strength. A male standing erect can be 5–6 feet (1.5–1.8 m) tall and weigh 300–600 pounds (140–270 kg) Males in captivity, however, are noted to be capable of reaching weights up to 275 kg. Females stand 5 feet (1.5 m) tall and weigh half as much as males.
It has been said that a silverback gorilla in his prime has the physical strength of seven or eight Olympic weightlifters. Western gorillas frequently stand upright, but walk in a hunched, quadrupedal fashion This style of movement requires long arms, which works for western gorillas because the armspan of gorillas is larger than their standing height. The hair on the back and rump of males takes on a grey coloration and is also lost as they get progressively older. This coloration is the reason why older males are known as "silverbacks".
Bush meat hunting and timber harvesting in the western lowland gorilla’s habitat have negatively affected the probability of its survival and, unfortunately, it is considered to be critically endangered by the IUCN. The western lowland gorillas, like many gorillas, are essential to the composition of the rainforest due to their seed distribution. The conservation of this magnificent animal has been made a priority by many organizations. The Wildlife Conservation Society (WCS) has been working with the local community in the Congo Basin to establish wildlife management programs and are trying to limit the bush meat trade by enforcing laws and hunting restrictions and also helping the local people find new sources of protein.
Zoos worldwide have a population of 550 western lowland gorillas.