Today we are going to talk about Cross River Gorilla. It was named a new species in 1904 by Paul Matschie. These types of species come from the western gorilla. So let's collect some more information about The Cross River Gorilla. Here we also talked about cross river’s Behavior & Distribution and Habitat. So let’s get some more information about it.
Overview
Here we discuss some topics about cross river gorillas like their Habitat, anatomy, reproduction, communication, distribution and all the information about gorillas. The Cross River Gorilla is Africa's most endangered great ape.
By Paul Matschie Cross River Gorilla was named a new species in 1904. The Cross River gorilla is a subspecies of the western gorilla. Cross River gorilla is the most western and northern form of gorilla. And they are restricted to the forested hills and mountains of the Cameroon-Nigeria border region.
The Cross River gorilla is separated by about 300 km from the nearest population of western lowland gorillas. And also it is separated by around 250 km from the gorilla population in the Ebo Forest of Cameroon. The Cross River gorillas remain and make them the world's rarest great ape. These gorillas Groups is concentrate their activities in 11 localities across a 12,000 km2 range.
It is though recent field surveys confirmed the presence of gorillas outside of their known localities suggesting a wider distribution within this range. The Cross River gorilla was finally captured on professional video on a forested mountain in Cameroon in 2009. The gorilla is the largest of all primates.
Cross River gorillas are bigger than chimpanzees, orangutans, and gibbons. There are two species of Gorillas, the Eastern Gorilla and the Western Gorilla; they both have a couple of subspecies. The Eastern Gorilla is considered endangered when the Western Gorilla is considered critically endangered. It is an evolutionary puzzle that gives them the conditions to survive in the place where they live.
In these species most of the time is not an exclusive area for the animal but shares it with other species. They interact with other animals of the same species or to defend it, animals have developed different forms of communication that allow them to transmit information for a variety of purposes.
Usually they need to reproduce and exchange reproductive cells with another individual of the same species. These species may not have spread much since their isolation.
Behavior & Distribution and Habitat
In 1904 The Cross River gorilla was first described as a new species of the western gorilla by Paul Matschie, a mammalian taxonomist. When we are comparing the Cross River gorilla to western lowland gorillas, they have noticeably smaller palates.
These species of gorilla are not known to differ much in terms of body size or limb and bone length from western lowland gorillas. The Cross River gorilla has the largest living primate with a barrel-chest, relatively even hair, a bare black face and chest, small ears, bare shaped brows that are joined, and nostril margins that are raised.
The cross river gorillas’ statistics are given below:
- Average adult male height : 165–175 cm
- Average adult male weight : 140–200 kg
- Average adult female height : 140 cm
- Average adult female weight : 100 kg
Behavior
They have certain nesting behaviors that depend on things like their current habitat, climate, food source availability and risk of attack or vulnerability. The Cross River gorillas are more likely to build their nests within a tree, from April up until November. And from November on they are more likely to build it on the ground.
The cross river gorilla found that more nests built at night were built on the ground as opposed to in trees. Cross River Gorilla is also more likely to construct nests during the wet season than the dry season. As well as they construct more arboreal nests in the wet season. Especially in the wet season, it was found that day nest construction was more common. Reuse of nesting sites was also found to be common.
They did not have any relation to the season. The cross river gorillas nest group size is from four to seven individuals. Their nest group size varies depending on the location of the species. In the groups of Cross River gorillas consist mainly of one male and six to seven females.
They are quiet animals. They do not usually go around terrorizing people with their roars and blows to the chest. This is a characteristic behavior of a silverback gorilla.
Diet
Their diet consists largely of fruit, herbaceous vegetation, liana, and also they eat tree bark. The gorilla indicates that it seems to prefer fruit, but will settle for other sources of nutrition during the dry season of about 4–5 months in northern regions.
They eat more liana and tree bark throughout the year. And they eat less fruit during dry periods of scarcity. Their food sources are very seasonal and thus their diets are filled with very dense food.
In the wet season, they preferred to eat Amorphophallus difformis over the Aframomum, showing preference for certain foods that were seasonal and also an affinity to the vegetation that was only found in their habitat.
Nesting
By the environmental conditions the nesting behavior of the Cross River gorilla was influenced. It is like the climate, predation, herbaceous vegetation, absence of suitable nest building materials and seasonal fruits nearby.
The gorillas did portray certain nesting habits. It is like mean nest group sizes, size and type of nest created. As well as reusing certain nesting locations nearby seasonal food sources.
During the dry season most of the nests were made on the ground, yet during the wet season the majority of the nests were made high up in the trees, to provide protection from the rain.
These gorillas created more day nests during the wet season. Some gorillas may have made multiple nests. The cross river gorillas mean group size was 4-7 individuals. They mean nest size at the sites was 12.4 nests and the most frequent number of nests was 13.
Aggression
The cross river gorillas have been observed in three separate cases. The Cross River gorilla at the Kagwene Mountain in Cameroon has been observed using tools and it seems to be unique.
Habitat
The Cross River gorilla’s body size is large and diverse areas of the forest to meet their habitat requirements. They are similar to most endangered primates. Their natural habitat exists where humans are often occupying and using for natural resources.
Data were collected, and things such as habitat types and topography mapped using line transects, climate, spatial and temporal availability of tree and herb foods and also the Cross River gorilla's wide range behavior, diet, and its grouping patterns is a great deal. All assessed from indirect evidence, such as feeding trails, nests, and feces.
The habitats of the Cross River gorilla are negatively affected by the drastic deforestation and also fragmentation of the land. As a result of deforestation and fragmentation, there are drastic reductions in carrying capacity.
Studies have found that an adequate amount of rainforest still remains that is suitable and comfortable for this subspecies. Gorillas and other primates are only a small part of the larger ecosystem. And also they rely on many aspects of their habitat for survival.
Because of their body size, they lack the ability to adapt to new environments and they have a rather slow reproductive rate. The Cross River gorilla is not only a critically endangered species compared to other subspecies.
The first point to consider is that gorillas live in Central Africa. The western gorilla lives in a region toward the west of the continent, while the other species, the eastern gorilla, evidently lives in the east.
Due to the fact that the species are in separate regions, they have diverse habitats, located at different altitudes. A habitat is an area with the appropriate conditions for the development of an organism.
This species of gorilla is separated by the Congo River; it is known that they thrive in the tropical and subtropical forests that run along the equatorial belt, almost by the middle of the African continent.
The Cross River Gorilla rarely drinks water directly from a river or lake, as they obtain it from their vegetable foods.
The main characteristic of the gorilla habitat is abundant and green vegetation.
In a tropical forest gorillas live at a temperature of around 23-celsius degrees. They can live in other types of habitat like: dense old-growth forests, areas along the edges of forests with high concentrations of low vegetation, mountain and sub-mountain forests, swamp forests and savannah forests. Each subspecies is found in particular habitats.
Size, Weight, and Lifespan
Cross River gorillas stand 4.7 to 5.5 feet tall and weigh between 100 to 200 kg. Lifespan of the Cross River gorilla in the wild is 35 to 50 years.
Distribution
The Cross River Gorilla is populated at the border between Nigeria and Cameroon, in both tropical and subtropical moist broadleaf forests.
The man degrades and reduces their habitat to perform agricultural or farming activities and to build human settlements. The gorillas are living smaller as human activities expand.
Gorillas are present in the following African countries: Angola (Cabinda province), Democratic Republic of Congo, Cameroon, Central African Republic, Equatorial Guinea, Congo, Nigeria, Uganda, Rwanda and Gabon. The areas where the gorillas live are diverse.
The Cross River gorilla looks like as western and northern form of gorilla. It is restricted to the forested hills and mountains of the Cameroon-Nigeria border region at the headwaters of the Cross River.
One recent field survey confirmed the presence of gorillas outside of their known localities suggesting a wider distribution within this range. These places cover a mostly continuous forest area of about 8,000 km2 from Afi Mountain to Kagwene Mountain.
They are known to cling to the Afi-to-Kagwene landscape.
Habitat loss
From other sub-populations of the species Cross River gorillas reside in small populations. Habitat loss is now posing a much bigger threat to the cross river gorilla and their survival. By anthropogenic factors Nest distribution was clearly influenced within the sanctuary.
Current wildlife laws regarding the areas are in place. Cross River gorillas will not build nests in areas near humans. The highway and its buffer zone would have had a significant impact on the remaining habitat.
Fragmented Population
The increased population of human inhabitants and the expansion of grasslands have caused a fragmentation of the species into many sub-populations.
Many factors contributed to the fragmentation of the population, including the expansion of farmland, human occupation, and lack of accessible habitat. One researcher found that gene flow accompanied the divergence of western lowland and Cross River gorillas until just 400 or so years ago.
Over the last several hundred years the recent decrease in the Cross River population is accordingly most likely attributable to increasing anthropogenic pressure.
Hunt
The commercialization of bushmeat hunting has caused a large impact on the population. A law preventing hunting still persists due to local consumption and trade to other countries.
Their hunting seems to be more intense within the lowlands. And also they may have contributed to the concentration of gorillas within the highlands and their small population sizes.
Cross River Gorilla Diet
The Cross River gorilla's diet consists largely of fruit, herbaceous vegetation, liana, and also they eat tree bark.
The Cross River gorilla indicates that it seems to prefer fruit. But they will settle for other sources of nutrition during the dry season of about 4–5 months in northern regions.
Cross River gorillas eat more liana and tree bark throughout the year. And they eat less fruit during dry periods of scarcity. The Cross River gorilla food sources are very seasonal. Also their diets are filled with very dense food.
In the wet season, they preferred to eat Amorphophallus difformis over the Aframomum, showing preference for certain foods that were seasonal and also an affinity to the vegetation that was only found in their habitat.
Amazing Facts about the Cross River Gorilla
Here we know some basic and amazing facts about the cross river gorilla. This communication is an important fact.
This type of species is a subspecies of the Western Gorilla.
In the wild there are currently only 200-300 Cross River Gorillas left.
They live in the mountainous border area between Cameroon and Nigeria at the top of the Cross River as their name.
The entire population is spread over an area of about 3000 sq miles. It is twice the size of Rhode Island.
These Gorillas have been hunted extensively in the past, meaning the remaining population is shy.
And also they avoid human contact.
The Cross River Gorilla is the tiny remaining population. Their genetic diversity is low, leaving the population less able to adapt and cope with diseases.
They are under threat as their habitat continues to be lost as a result of deforestation.
They are a protected species; hunting for bushmeat continues to be a problem, with an estimated 1-3 Cross River Gorillas lost to poachers every year.
Communication
In the cross river gorilla the most important fact is communication. How they communicate with each other and humans are known in this topic. So, let’s know about communication of this species.
All gorillas communicate with one another through a variety of vocalizations. They communicate each with a specific meaning.
The cross river gorilla used different sounds during play, mating, or when a predator is sighted. Scientists have determined 22 different gorilla vocalizations.
They have attested that gorilla behavior and emotions are similar to the human experience. Perhaps the most intimidating display of posturing is when a silverback stands upright and beats his chest.
International awareness remains keys to the Cross River gorillas’ survival. Back from the brink conservation efforts are underway in Cameroon and Nigeria to bring the tiny population of Cross River Gorillas.
Reproduction
The Cross River gorilla is a polygamous animal. Since then the dominant male has the privilege of mating with all sexually mature females in his group. There is very little information about their reproduction.
The gestation period is similar to the other gorillas between 8.5 – 9 months and females breastfeed and take care of their young during their initial years of their life.
The Cross River gorillas are slightly smaller than the eastern gorilla subspecies, with a more slender build, shorter and lighter-colored hair, longer arms, and a more prominent ridge line.
The coats of Cross River gorillas are typically brownish gray to black, and they have auburn-colored chests.
Reproduction and Family
The cross river gorilla is grooming each other is a favorite gorilla pastime and establishes social bonds. In their group both male and female young gorillas might leave their birth groups.
The Cross River Gorilla troops are led and protected by an alpha male, who is a mature silverback. Besides protecting his troop from outside threats, a dominant male silverback will intervene when members of his harem become overly aggressive with one another as they compete for the silverback’s attention.
These species, an adult member of the troop, behave too roughly with one of the troop’s infants. Males attain silverback status at about 12 years old. These species are continued to develop until age 15.
The alpha silverback male has special privileges with the females. He mates with each of them. Females reach breeding age at ten years old and after a gestation period of about 8.5 to 9 months.
Nursing mothers are unable to become pregnant and typically give birth every four or five years. Their infant is fully weaned.
Baby gorillas are tiny and vulnerable. Baby gorillas are requiring much maternal care. The cross river gorilla baby needs the first five months of their lives, they are in constant physical contact with their mothers.
Mothers keep close to the silverback for protection. As the babies grow up, they begin playing with other members of the troop. It includes their silverback dad who is gentle with his offspring.
Females are inclined to leave their birth group if the dominant silverback dies. Males wishing to establish their own group and have their own female harem typically leave their birth group. Several gorillas may travel together for years in so-called “bachelor groups”. They travel together until they become silverbacks and realize their goal.
Inbreeding is a consequence of this isolation and dilutes the genetic diversity of these types of subspecies.
Related Species
Here we are talking about Cross River Gorilla as well as talk about their related species. Related species of Cross River Gorilla are given below. So, let’s collect some information about Cross River Gorillas related species.
- Orangutan
- Gorilla
- Mountain gorilla
- Bonobo monkey
- Black spider monkey
- Chimpanzee
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