Western Lowland Gorilla

Gorillas are generally herbivores. They eat mainly juicy stemmed plants, but they also consume leaves, berries, ferns, and fibrous bark. They will also eat ants and termites.

At the Zoo, gorillas enjoy a diet of greens, assorted vegetables, a special formulated biscuit for primates, a small amount of fruit, and assorted browse. They also receive starch balls and popcorn for enrichment.

Currently found in Gabon, Central African Republic (CAR), Cameroon, Angola, Equatorial Guinea, Democratic Republic of Congo (DRC), Republic of Congo. Until recently, the core population had an almost continuous distribution from southern CAR to the Congo River and west to the coast.

This species lives in lowland and swamp forests.

Predation on adult gorillas is not common. Young gorillas may be vulnerable to large raptors and carnivores.

Habitat destruction and deforestation caused by palm oil plantations, mining, and human settlements are the primary threats to gorillas. Additionally, infectious diseases negatively affect their populations. Although there are laws in place prohibiting their capture and hunting in all eight countries of their native range, poaching continues to pose a significant threat to western lowland gorillas.

Coarse, dark hair covers their body except for the face, ears, hands, and feet. Their skin is jet black. As males enter adulthood, they develop a broad, silvery white saddle of hair along the back, extending over their rump as they age. This coloration pattern has resulted in older males being known as "silverbacks." Males develop a prominent sagittal crest (the point where the jaw muscles attach to the top of the skull) and long, dark arm hair. On average, males turn silver around twelve to thirteen years old but do not reach full size until about fifteen years.

Western gorillas' hands are proportionately large, with nails on all digits and very large thumbs. They frequently stand upright but walk using all four limbs, with hands curled and knuckles touching the ground. Walking this way requires long arms, and gorillas' arm spans are longer than their standing height.

Typically, gorillas live in groups called harems, where one dominant male within a gorilla troop mates with the females in that group. Gorillas breed year-round. Females reach breeding maturity around ten years, and males around fifteen years.

After about eight and a half months, a pregnant female will give birth to a single offspring weighing between 3.5 and 5.5 pounds. Twins are rare. Young gorillas nurse and depend on their mother for three to four years. Because of this, she will generally reproduce every four or more years. Females provide the young with transportation, food, and socialization.

Much of gorilla communication is through body language. Tight body posture, avoiding eye contact, and pursed lips can be signs of anger or aggression. Loose body language, including chest-beating, can reflect a desire to play. Direct eye contact can be interpreted as aggression, especially in the case of the silverback. Touch and physical contact also play an important role in communication and social structure.

Gorillas have more than twenty distinct vocalizations, including laughter, grumbling (“happy”), coughing (“back off”), and barking (“danger”).

Gorillas are generally peaceful, shy, and amiable unless threatened. Male gorillas will charge toward perceived intruders but rarely hit them. If the threat persists, they may charge again.

Gorillas live in close-knit groups called troops, usually consisting of one dominant male, many adult females, and their young. The silverback heads the group as long as he can defeat competing males, although he may ultimately be driven out to live a solitary life. Young silverbacks are often driven out of the group and may spend several years alone or with other young males before establishing their own group. A hierarchy exists with females in the troop, as well. Females will often migrate to a neighboring group when they become sexually mature.

Gorillas are nest builders and will generally create a new nest of foliage every night to sleep in.