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Western Lowland Gorilla

Gorilla gorilla gorilla

About the Western Lowland Gorilla

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Geographic Range:

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Class: Mammalia
Order: Primates
Family: Hominidae
Genus: Gorilla
Species: gorilla
Subspecies: gorilla

Gorillas are the world’s largest living primates. Male western lowland gorillas can grow to 5.5-feet tall and weigh up to 450 pounds. Females can grow to 4.5-feet tall and weigh up to 250 pounds. Western lowland gorillas live in groups, or “bands” in or near African forests. The alpha male leads the band and those who challenge him are apt to be cowed by impressive shows of physical power—he may throw things, make aggressive charges, pound his huge chest while barking out powerful hoots, or unleash a frightening roar.

Gorilla Facts

Appearance:
The western lowland gorilla has dark brown to black fur and black skin. Facial features include a prominent brow ridge, small eyes and ears, large nostrils and short muzzles. Gorillas have broad, strong teeth and large jaw muscles. Coarse black to brown hair covers the body except for the face, hands and feet. The hair of mature males from shoulders to rump grows gray with age giving them the nickname "silverback." Males have an enlarged sagittal crest, which is a bone ridge on the top of the cranium.

Size:
Height: Males up to 5.5 feet tall; females up to 4.5 feet
Weight: Males up to 450 pounds; females up to 250 pounds

Diet:
Gorillas eat more than 200 types of plants including fruits, flowers, shoots, bulbs, bark and leaves, as well as invertebrates (like ants and termites).

Reproduction:
Gorillas don't have a breeding season. The female's estrus cycle occurs every 30-33 days. Usually only the dominant silverback male gets to breed, but sometimes a troupe is led by multiple younger males (called “black backs” due to the lack of silver coloration on their back).

Gestation:
Lasting 250 to 285 days, gestation usually results in one offspring (twins are rare). Young are weaned after 36 to 48 months. Males reach sexual maturity in 6-11 years and females in 6-8 years. When mature, both genders leave their group to find another to prevent inbreeding.

Behavior:
Western lowland gorilla groups generally consist of one dominant silverback male and multiple females and their offspring. At times gorilla groups may consist of multiple males with more than one silverback or multiple younger males. Their group size in the wild generally averages eight individuals, but groups as large as 20 have been recorded. The silverback male responds to challenges made against him by an intimidating display. He may make aggressive charges, stand upright and pound his huge chest while barking out powerful hoots or even throw things.

Due to their dependence on seasonal fruit, western lowland gorillas have the largest home range of the four gorilla subspecies. They spend most of their time on the ground, although the young may spend some time in the lower canopy while foraging. Gorillas build nests for both day and night. Night nests consist of branches and leaves; day nests provide a cushion on the ground.

Habitat/Range:
Tropical forests, swamp forests, clearings and forest edges in the African countries of Cameroon, Gabon, Central African Republic, Republic of Congo, Equatorial Guinea, Cabinda (Angola), and possibly Democratic Republic of Congo although it is likely they are extinct there.

Median Life Expectancy:
Males: 31.7 years

Females: 38.3 years

Threats in the wild:
Gorilla numbers in the wild are declining at a rapid rate. Ebola virus (hemorrhagic fever) and the commercial bush meat trade, along with habitat loss and poaching are the main causes behind gorilla deaths. The loss of their forest habitat is a twofold threat since habitat loss also brings hungry people who hunt gorillas for bushmeat.

Committed to Conservation

Gorilla numbers in the wild are declining at a rapid rate. Ebola virus and the commercial bush meat trade, along with extreme habitat loss and poaching are the main causes behind gorilla deaths. As a result, the western lowland gorilla’s numbers have declined by more than 60% over the last 20 to 25 years. According to the World Wildlife Federation, even if all of the threats to this species were removed, scientists calculate that the population would require some 75 years to recover. To that end, Zoo New England has been an active participant in gorilla conservation through the following programs and initiatives:

APE Tag Conservation Initiative

The Ape TAG Conservation Initiative is a collective effort by zoos to help conserve wild populations of endangered apes in their natural habitats. Projects range from species monitoring and protection to law enforcement, ecotourism, and veterinary and disease monitoring. All projects include the local communities. These projects help gorillas, chimpanzees, bonobos, orangutans, gibbons and their habitats. More

AZA SAFE

Zoo New England is proud to support the Association of Zoos and Aquariums' SAFE initiative (Saving Animals from Extinction), a bold effort focused on #SavingSpecies. SAFE is a commitment by the Association's accredited zoos and aquariums to harness our collective resources, focus on specific endangered species, and save them from extinction by restoring healthy populations in the wild. 

To offset declines in two subspecies of gorilla, AZA organizations raised $7.7 million for gorilla conservation from 2013-2017 and project leaders for the SAFE gorilla program are developing action plans to address the current threats. In 2018, AZA members spent more than $1,684,000 to help save gorillas from extinction.

Cell Phone Donations

Electronic gadgets like cell phones, ipods and tables contain coltan, a mineral extracted from the forests of Africa. Mining for coltan destroys the natural habitat of gorillas and many other species, pushing these animals closer to extinction. Zoo New England has teamed up with Eco-Cell, a company that partners with zoos across the country, to collect your recycled cell phones and refurbish them for reuse. This reduces the need for more coltan, leads to less mining and destruction of habitat, and helps the gorillas! More

Species Survival Plan

Zoo New England participates in the Western lowland gorilla Species Survival Plan. By sharing research and knowledge, participating institutions work together to establish guidelines that best ensure the health of captive populations, and with success, the survival of otherwise extinct species. More

You Can Help!

  • Avoid palm oil: The presence of palm oil in everyday products — from the food we eat to the products we use for skincare — is widespread and is causing significant habitat loss and population declines. As consumers, one of the first steps we can take is to refuse to buy products that contain palm oil, thereby reducing the continued demand. Additionally, pressure must be put on companies to adopt sustainable and ecological-friendly practices for palm oil cultivation. More
  • Promote sustainable forestry: Human population growth does not mean that the survival of great apes is automatically threatened.  Sustainable forestry can lead to both the protection of great apes and further economic development. A good starting point for promoting sustainable development can be when you commit to purchasing paper and wood products that have been certified as sustainable by a reputable entity. You can learn more about the different types of eco-labelingMore
  • Recycle your cell phone: Many of us have old phones lying around our house that we don’t even use. These phones contain coltan, which is a material mined from the gorilla's natural habitat. When recycled, old electronics and chargers can have a major impact on the lives of gorillas. More