They are our closest living relatives after chimpanzees and bonobos.
Gorillas live in the forests of central Africa.
There are two gorilla species: the eastern gorillas (Gorilla beringei) and the western gorillas (Gorilla gorilla). The western gorilla lives in west central Africa, while the eastern gorilla lives in east central Africa. They are separated by about 900 kilometers (560 miles) of Congo Basin forest. [Gorilla (Gorilla) range map. Orange: Western Gorilla (Gorilla gorilla) Gold: Eastern Gorilla (Gorilla beringei)]
Each species has two subspecies.
Cross River gorilla (Gorilla gorilla diehli) – an estimated population of only 250-300 left in the wild
Western lowland gorilla (Gorilla gorilla gorilla) – an estimated population of over 100,000 left in the wild
Mountain gorilla (Gorilla beringei beringei) – an estimated population of about 880 left in the wild
Eastern lowland or Grauer’s gorilla (Gorilla beringei graueri) – an estimated population of under 5,000 left in the wild
Although their range covers a small percentage of Africa, gorillas cover a wide range of elevations. Lowland gorillas live in dense forests and lowland swamps and marshes as low as sea level. The mountain gorilla inhabits forests, ranging in altitude from 2,200–4,300 meters (7,200–14,100 ft).
A gorilla’s lifespan is normally between 35 and 40 years, although zoo gorillas may live for 50 years or more. Colo, a female western gorilla at the Columbus Zoo and Aquarium was the oldest known gorilla,at 60 years of age when she died on January 17, 2017.
Wild male gorillas weigh 135 to 180 kg (300 to 400 lb) while adult females usually weigh half as much as adult males at 70–115 kg (150–250 lb).
Adult males are 1.7 to 1.8 m (5 ft 7 in to 5 ft 11 in) tall, with an arm span that stretches from 2.3 to 2.6 m (7 ft 7 in to 8 ft 6 in). Female gorillas are shorter, with smaller arm spans.
Gorillas are stocky animals with broad chests and shoulders, large hands, and forearms that are much shorter than the upper arm.
The face is black and hairless, with small eyes that are close together and large, prominent nostrils.
The eastern gorilla is more darkly coloured than the western gorilla, with the mountain gorilla being the darkest of all. The mountain gorilla also has the thickest hair. The western lowland gorilla can be brown or grayish with a reddish forehead.
Adult males are identified by a sagittal crest along the midline of the skull and an area of white hair on the back, which is why they are known as “silverbacks.”
Gorillas are non-territorial and live in groups called troops. There can be 5 to 30 gorillas in one troop, led by a strong, experienced silverback. The silverback makes all the decisions, such as where the troop travels for food each day, when they stop to eat or rest, and where they spend the night.
A gorilla troop doesn’t stay in the same place for more than a day. After all, the troop doesn’t want to deplete its food source! Each morning the silverback leads his troop to a new area where food is plentiful. After a morning of munching, each adult gorilla gathers leaves, twigs, and branches to make a day nest for resting while the youngsters play. After their nap, the gorillas eat again until bedtime, when they make yet another nest, either on the ground or in a tree, for a good night’s sleep. Gorillas never use the same nest twice.
Nest-building by great apes is now considered to be not just animal architecture, but as an important instance of tool use.
Gorillas have various methods of communication, including some 25 distinct vocalisations.
They are generally peaceful creatures, but sometimes a younger male from another troop will challenge the silverback. To scare unwanted gorillas away, he will beat his chest with cupped hands to make a loud noise, scream, bare his teeth, then charge forward. Sometimes he will break off branches and shake them at the intruder.
Gorillas stick to a mainly vegetarian diet, feeding on stems, bamboo shoots and fruits. Western lowland gorillas, however, also have an appetite for termites and ants, and break open termite nests to eat the larvae.
Gorillas rarely drink water “because they consume succulent vegetation that is comprised of almost half water as well as morning dew.”
Females mature at 10–12 years, and males at 11–13 years.
Gorillas mate year round. The gestation period lasts 8.5 months. Newborn gorillas weigh about 1.4 to 1.8 kilograms (3 to 4 pounds). A mother carries her baby against her chest for the first several months until the little one can hang on to Mom’s back, which frees up her hands to walk and carry food items.
At five to six months old it learns to walk, and by 18 months of age it can follow mom on foot for short distances. Still, the safest place for the younster is its mother’s back as she travels thru the dense vegetation of their forest home.
Young gorillas learn by imitating what the others in the troop are doing and by play fighting with other youngsters. Even the stern silverbacks are gentle with the little ones as they practice new
skills. A young gorilla stays close to its mom, sharing her nest, until it is four to six years old.
Gorillas have no natural enemies or predators, yet these peaceful creatures are at critical risk because of humans. People hunt gorillas for food called bushmeat, and logging and mining companies destroy gorilla habitat.
All species (and sub-species) of gorilla are listed as Critically Endangered on the IUCN Red List.
Disease epidemics such as the Ebola virus have recently decimated gorilla populations that were previously considered secure within their natural habitat.
Gorillas are considered highly intelligent. One famous captive-born individual, Koko, has been taught sign language since she was a year old. By the age of 40, she had a library of about 1,000 signs and could understand some 2,000 words of English.
Like the other great apes, gorillas can laugh, grieve, have “rich emotional lives”, develop strong family bonds, make and use tools, and think about the past and future.
Some researchers believe gorillas have spiritual feelings or religious sentiments.
Like the other apes and humans, gorillas cannot swim naturally, therefore they avoid large bodies of water and rivers.
Gorillas can run at speed in excess of 20 mph (32 km/h) and can reach a top speed of 25 mph (40 km/h) when needed.
No two noses on a gorilla are alike. Researchers take close-up photos of each wild gorilla’s face to help identify individuals.
The DNA of gorillas is highly similar to that of humans, from 95–99% depending on what is counted.
The word “gorilla” is from a Greek word meaning “tribe of hairy women.”
Since coming to the attention of western society in the 1860s, gorillas have been a recurring element of many aspects of popular culture and media. For example, gorillas have featured prominently in monstrous fantasy films such as King Kong.