Western gorilla

Gorillas eat mostly plants.

They munch leaves, stems and juicy fruit. Sometimes they eat tiny bugs on the leaves too.

Gorillas are mostly herbivores. They eat the leaves and stems of herbs, shrubs and vines, and western lowland gorillas also eat a lot of fruit, from close to a hundred kinds of trees that fruit in different seasons.

They get a little extra protein from insects and other small animals that live on leaves and fruit. When fruit is plentiful, a group travels farther to find it. A big male eats far more than a female, about one and a half times as much.

The diet is primarily herbivorous: leaves, stems and pith of herbs, shrubs and vines, plus the fleshy fruits of close to a hundred seasonally fruiting tree species. Western lowland gorillas are more frugivorous than other gorilla subspecies, and their daily travel increases when fruit is abundant.

Invertebrates eaten along with leaves and fruit supply some protein. Adult females eat about two-thirds as much as adult males. Gorillas digest high-fiber food inefficiently, and the National Zoo notes that the occasional eating of feces seen in the wild lets them recover nutrients from undigested food.

Gorillas live in family groups.

The silverback is the leader. He keeps his family safe. Every night, each gorilla makes a soft bed of leaves.

A western lowland gorilla group is small, often about five gorillas: a silverback, a few adult females and their young. The silverback decides when the group wakes up, eats and sleeps, and settles arguments.

Gorillas are quiet and peaceful. Every evening each one bends branches and leaves into a nest to sleep in. If a silverback feels his family is in danger, he stands up, beats his chest and roars, and may charge forward, but he usually runs past without touching anyone. Scientists have counted up to 22 different gorilla calls.

Groups typically contain one silverback, sometimes younger blackback males, several adult females and their offspring; western lowland groups average about five individuals. The silverback leads, mediates disputes and sets the group's range and daily schedule. Females usually leave their birth group at about eight, choosing which male to join.

Gorillas build day nests for resting and night nests for sleeping. Communication uses at least 22 recorded vocalizations, gestures, postures and odors. Threat displays (standing, chest-beating, roaring and bluff charges that usually stop short of contact) help keep order between groups without injury.

There are fewer gorillas than there used to be.

Many people are working to help them. Rangers protect the forests. Visitors who come to watch gorillas help pay for that care.

The western gorilla is critically endangered. Over about 20 to 25 years its numbers fell by more than 60 percent. Gorillas have been hunted illegally for meat, logging roads have opened up their forests, and a disease called Ebola has killed many gorillas and chimpanzees.

There is hope. A 2018 study found that more than 360,000 western gorillas still live in the forests, many more than once thought. Parks protect them, and in places such as Dzanga-Sangha in the Central African Republic, careful gorilla tourism provides local jobs that help pay to protect the forest.

The IUCN moved the western gorilla from Endangered to Critically Endangered in 2007. Commercial bushmeat hunting, the Ebola virus and logging, which fragments forest and opens access for hunters, drove declines of more than 60 percent over 20 to 25 years; WWF reports Ebola losses of over 90 percent of gorillas and chimpanzees in Gabon's Minkébé Forest.

A 2018 study estimated more than 360,000 gorillas in western equatorial Africa, but about 80 percent live outside protected areas. Scientists calculate that even if all threats stopped, recovery would take about 75 years. Responses include protected-area networks, anti-poaching work, disease monitoring and community-based gorilla tourism.