Gorilla

Gorillas, the largest of the living primates, are ground-dwelling omnivores that inhabit the forests of Africa. Gorillas are divided into two species and (still under debate as of 2007) either four or five subspecies. Its DNA is 97%–98% identical to that of a human,[2][3] and are the next closest living relatives to humans after the two chimpanzee species.

Physical characteristics

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 ft) and 225 kg (500 lb) has been recorded in the wild. However, obese gorillas in captivity have reached a weight of 270 kg (600 lb).[5] Gorillas have a facial structure which is described as mandibular prognathism, that is, their mandible protrudes farther 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 10–12 years (earlier in captivity); males at 11–13 years. Lifespan is between 30–50 years. The Philadelphia Zoo's Massa set the longevity record of 54 years at the time of his death.[6]

Gorillas are omnivores, eating fruits, leaves, shoots, and sometimes insects which make up only 1–2% of their diet. [7]

Almost all gorillas share the same blood type (B)[8] and, like humans, have individual finger prints.

Behavior

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. 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 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.

Males will slowly begin to leave their original troop when they are 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.