Cross River Gorilla

Quick Take

• Only a handful of these gorillas exist, yet most people have never heard of them. Discover why they're considered the world's strangest great ape. Discover the key facts →
• Climate change shaped this gorilla into its own subspecies, and the timeline of when it happened might surprise you. See how climate shaped them →
• Local farmers say this critically endangered ape is less destructive to their land than a much smaller animal, which makes for a surprisingly unexpected comparison. Read about farmland conflicts →
• The last zoo on Earth to display one of these gorillas saw that story come to an end in 2016, and no zoo has managed to host one since. Explore the captive history →

The Cross River gorilla (Gorilla gorilla diehli) is a subspecies of the western gorilla. Paul Matschie, in 1904, named the Cross River gorilla a new species; it has since become increasingly rare.

These gorillas have brownish-grey or black fur. However, the face, hands, and feet have no fur at all. They have cone-shaped heads, above which rests a reddish crest. These gorillas are very social and usually live in groups of 2 to 20. The groups are led by a dominant male. Apart from the dominant leader, there are 6 to 7 females and their children.

Cross River gorillas reach sexual maturity at around 7 to 8 years for females and 11 to 13 years for males, and usually have babies every 4 years. Their gestation period usually lasts about eight and a half months. These gorillas live in the mountainous region between Nigeria and Cameroon. The Cross River gorillas are herbivores and usually feed on branches, nuts, leaves, and berries that they forage from different plants.

The Cross River gorillas are known to be highly efficient in infant care and are known to care for their babies up until they are three to four years of age. During this time, they do not reproduce again and give their full attention to their newborn baby.

Incredible Cross River Gorilla Facts

• Known as the world’s strangest gorillas, the Cross River gorillas are small in population and are rarely seen.
• Cross River gorillas are critically endangered — there are only 200 to 300 left in the world.
• They are the most endangered great ape in Africa.
• They are usually found at the borders between Nigeria and Cameroon.
• Most of their day is spent eating.

Evolution And Origin

The Cross River gorilla is a subspecies of the western gorilla, which scientists believed originated from a genus of proto-primates that were around at the end of the Cretaceous period. It is believed that the western species of gorilla diverged into its own genus during the Pleistocene epoch, and the Cross River gorilla was further shaped into its own subspecies around 17,800 years ago due to climate change.

Classification and Scientific Name

The Cross River gorilla goes by the scientific name “Gorilla gorilla diehli” and belongs to the kingdom Animalia and class Mammalia. They belong to the phylum Chordata and order Primates. They also belong to the family Hominidae and the genus Gorilla.

Appearance And Behavior

Cross River gorillas have a slender yet short build, paired with light-colored hair. These gorillas have long arms and a prominent ridgeline, which offers a striking contrast to the flat face and wide nostrils. Their dark eyes are concealed by fur, which is often either black or brownish-gray.

The face usually has no fur, just like the hands and feet. Their heads are cone-shaped, and they have a red-colored crest on their heads. The group leaders, who are dominant males, often have a silver patch on their backs, which is also why they are called silverbacks.

Cross River gorillas are social and live in family groups of 2 to 20 individuals. Their behavior is very similar to other gorillas. The group is usually led by a silverback male as the dominant leader.

The male leader is usually responsible for taking care of the females and children of the group and also often makes the key decisions of the group, like the feeding and nesting sites. Nesting happens in forests after these gorillas build nests with branches and leaves. The nesting places are usually on the ground.

However, the nesting places change in the rainy season when they shift their nests to the tops of trees. Most of their day is spent eating. However, sources suggest that they also indulge in recreational activities like grooming.

These gorillas are usually known to be peaceful. However, they may sometimes turn aggressive toward humans when threatened. They may attack humans with branches, stones, and other objects if provoked.

Habitat

Known as the world’s strangest gorillas, the Cross River gorillas are small in population and are rarely ever seen. They are usually found on the mountainous borders of Nigeria and Cameroon. This habitat of theirs is called the Cross River basin.

These animals are known to inhabit most North and West African regions. They also exist in the Afi Mountains in Nigeria and the Cameroonian Mbe Mountains. Apart from that, they are also found in the Takamanda National Park of Cameroon and the Cross River National Park in Nigeria.

Most of these gorillas are found in lowland montane rainforests and bamboo forests, with bamboo forest habitats occurring at elevations of 8,202 to 9,843 feet (2,500 to 3,000 meters).

Diet

The foods found in the diets of the Cross River gorillas mainly consist of leaves, nuts, berries, and lianas, which are woody vines. These herbivorous gorillas will search as far as needed for nutrients, even venturing outside their typical foraging area.

If this gorilla species makes it down to the lowlands, they will likely come into conflict with local farmers who harvest bananas and plantains. Even though this damage may seem significant to the area, some local farmers have remarked that they are far less destructive to their land than other animals with a smaller stature, including wild pigs.

Cross River gorillas only seek food in other areas due to a lack of nutrition near their home range. Still, the only time in recent history that these beautiful mammals have caused significant damage was in 2006. This event is believed to have been the result of how close the farms were to the forest homes of the gorillas.

Predators And Threats

Like all the other living beings on the planet, the Cross River gorillas are also an important part of the ecosystem. However, they also face a lot of threats, both from other animals and from human beings. The predators of the Cross River gorillas include crocodiles and large jungle cats.

The Cross River gorilla is threatened by humans, as they were hunted extensively in the past, which is also why their numbers are pretty low. Human activities like deforestation also pose threats to these gorillas. The Cross River gorillas are the most endangered great apes in Africa.

The Cross River gorillas are critically endangered. As the population dwindles, some organizations are working to protect the forests in which they live, preventing them from venturing into local farmland and losing access to food sources. The World Wildlife Fund has multiple partners within the Nigerian and Cameroonian governments to protect certain areas.

Reproduction, Babies, And Lifespan

The Cross River gorillas reach maturity at around ten years of age. they usually give birth only once every four years or so, as they provide a very high level of infant care. They usually take care of their babies until they are three or four years of age. The gestation period usually lasts about nine months, which is also very similar to humans.

The Cross River gorillas are polygamous animals. The dominant male of the group usually mates with all the sexually mature females of his group. The female gorillas, after giving birth, breastfeed their babies and take care of them up until they are about three to four years of age. Usually, these gorillas give birth to single babies, and twins are a rare occurrence. The lifespan of these gorillas in the wild is usually 35 to 40 years, though they can live longer in captivity, sometimes exceeding 50 years.

Population

Since these gorillas are critically endangered due to hunting and other human activities like deforestation, there are only about 100 to 250 Cross River gorillas (mature individuals) left in the world. The majority of these gorillas are in Nigeria and Cameroon, spread out amongst no less than 11 families.

Efforts are therefore being made to make them live in designated places so that they can thrive in protected environments, since the Cross River gorilla population is still decreasing. Apart from their fragmented families, another trade has become highly lucrative and a major threat to the species: selling Cross River gorillas as pets.

Some people have kept the Cross River gorilla as pets, which is a dangerous trade that impacts the ability to conserve the species. Some hunters will kill a baby gorilla’s parent and take the infant to sell, as young gorillas are easy to handle. Currently, the combined threats of Ebola infection and hunting make recovery impossible in the short term. Still, there is hope that this species will recover from these threats within the next 75 years, as long as continued efforts are made to preserve their habitat.

In the Zoo

Due to the critically endangered status and the decreasing number of Cross River gorillas around the world, keeping them in a captive environment may allow these gorillas to thrive again. To view them in a zoo, there are many reserves and sanctuaries that host them, like the Afi Mountain Wildlife Sanctuary.

The Limbe Wildlife Center in Cameroon has been the only zoo to have one of these gorillas on display since 2007. The gorilla, named Nyango, died on October 10, 2016, from illness. There are no other reports of zoos that currently hold these mammals..

Despite not hosting these animals, many zoos and sanctuaries offer important facts about the Cross River gorilla to encourage patrons to support conservation.