Gorillas are ground-dwelling, herbivorous apes that occupy the wilderness of central Sub-Saharan Africa.
The genus Gorilla can be divided into two species that include the eastern gorillas and the western gorillas.
They are the largest living primates, and both species are in danger of extinction.
The DNA of gorillas is highly comparable to that of humans, having a comparison rate of 95% – 99%, relative to what is involved.
They are the following closest inhabiting relatives to humans after the bonobos and chimpanzees.
The natural homes of gorillas cover the tropical and subtropical forests in Sub-Saharan Africa.
Although their range surrounds a little proportion of Sub-Saharan Africa, gorillas cover a large extent of elevations.
The mountain gorilla occupies the Albertine Rift montane cloud forests of the Virunga Volcanoes, reaching an altitude between 2,200 & 4,300 meters.
Lowland gorillas inhabit dense forests and the lowland marshes, which are at sea level.
The western lowland gorillas live in Central West African countries, and eastern lowland gorillas reside in the Democratic Republic of the Congo close to its border with Rwanda.
Physical features of gorillas
Gorillas walk around with their knuckle, and they sometimes move like humans when carrying their food or in protective situations. Few mountain gorillas make use of different parts of their hand to support their movement. There is a unique difference in the regularity and comfort with which gorillas walk upright.
Studies have shown that distinctive gorillas at the London Zoo and Philadelphia Zoo have been detected walking straight more often and for extended periods than usual. A gorilla at the Philadelphia Zoo, called Louis, have been observed to do this to avoid getting dirt on his hands.
Adult male gorillas body weighs between 136 – 227 kg (300 – 500 lb) and a height between 1.4 – 1.8 m (4 ft 7 in – 5 ft 11 in). They also possess an arms-length that extends from 2.3 – 2.6 m (7 ft 7 in – 8 ft 6 in). Adult male gorillas are also called silverbacks because of the distinctive silver hair on their backs, reaching to their hips.
Adult females weigh between 68 – 113 kg (150 – 250 lb), and they have a height of 1.25 – 1.5 m (4 ft 1 in – 4 ft 11 in), with smaller arm size. The eastern gorilla is darker in colour than the western gorilla, with the mountain gorilla being the shadiest of them all. The mountain gorilla is also known to have the thickest hair, while the western lowland gorilla has a greyish or brown colour with a reddish forehead.
Also, gorillas that dwell in lowland forests are more slim and active than the massive mountain gorillas. The eastern gorilla also possesses an extended face and broader chest than the western gorilla.
Researches have demonstrated that gorilla’s blood doesn’t react to anti-A and anti-B monoclonal antibodies, unlike in humans that indicate a type O blood. According to novel sequences, it is distinct enough that it doesn’t correspond with the human ABO blood group structure. However, other giant apes fit into this category.
Like humans, gorillas have unique fingerprints, and their eye colour is grey-brown, a black ring around the iris frames it. The lifespan of a gorilla is generally between 35 and 40 years, although zoo gorillas could live for over 50 years.
A female gorilla at the Columbus Zoo & Aquarium, named Colo, was the oldest recognized gorilla. She passed on the 17th of January 2017 at the age of 60 years.
Habitats and Distribution
Gorillas have an irregular distribution. The Congo River and its tributaries separate the range of the two species of gorilla. The eastern gorilla dwells in east-central Africa, while the western gorilla inhabits west-central Africa.
Gorilla natural surrounding ranges from montane forest to swampland. Eastern gorillas reside in montane and submontane forests between 650 – 4,000 m (2,130 – 13,120 ft) above water level.
Gorillas build nests for day and nighttime use. Nests are the natural accumulations of branches and leave together, and it is about 2 – 5 ft (0.61 – 1.52 m) in diameter. Unlike chimpanzees, gorillas are more inclined to rest in nests on the ground.
The young nest with their mothers, but build their nests after they’re three years of age.
Diet and Scavenging
A gorilla’s day is divided into two periods that include the resting periods and feeding or travel periods—the food they consume varies between and within the species.
Mountain gorillas mainly eat vegetation, such as leaves, pith, stems, and shoots, while fruit consumption makes up a tiny part of their sustenances. Mountain gorilla food is extensively dispersed, and neither groups nor individuals need to compete with one another.
Eastern lowland gorillas have different diets, which range seasonally. Piths and leaves are generally eaten, but fruits make about 25% of their diets. They also consume insects, preferably ants.
Western lowland gorillas live on fruits more than the others, and they are more scattered across their range. They have limited access to terrestrial plants, but western lowland gorillas have access to aquatic herbs in some regions. Western lowland gorillas also consume ants and termites.
Gorillas hardly drink water because they eat juicy foliage that is constituted of almost half water as and morning dew. However, both mountain and lowland gorillas have been seen drinking water.
Gorillas living in groups are called troops. Troops are generally made of a single adult male or silverback, numerous adult females and their offspring. However, multiple-male troops can also exist.
Mature male gorillas are more inclined to vacate their groups and create their troops by luring migrating females. Nevertheless, male mountain gorillas occasionally remain in their birth troops and become subject to the silverback.
If the silverback departs, these males may be eligible to become prominent or mate with the females. Nevertheless, this behaviour has not been seen in eastern lowland gorillas.
In an individual male group, when the silverback dies, the female gorillas and their offspring distribute to find a new troop. Without a silverback to defend them, the newborns are likely to fall victim to infanticide.
One apparent predator of gorillas is the leopard. Gorilla remnants have been discovered in leopard faeces, but this might be the result of foraging.
When the troop is ambushed by leopards, humans, or other gorillas, a single silverback will defend the group, even at the expense of its life.
Reproduction and Copulation
Female gorillas mature at 10–12 years and the males at 11–13 years. A female’s initial ovulatory cycle starts when she is six years of age and accompanied by two years of young infertility. The oestrous process persists for about 30 – 33 days, with external ovulation cues related to those of chimpanzees.
The gestation duration lasts for about 8.5 months. Female mountain gorillas give birth to their first offspring at the age of 10 years and have four-year interbirth spans. Male mountain gorilla can be fertile before attaining adulthood. Gorillas mate all year-round.
Females will press together their lips and gradually move toward a male while making eye contact. This serves to encourage the male to mount her. If the male does not react, she will attempt to draw his attention by moving towards him or banging the ground.
In multiple-male factions, solicitation suggests a female choice, although female gorillas can be compelled to mate with many males. Males incite intercourse by moving toward a female and caressing her and giving a train grunt.
Lately, gorillas have been seen directly facing themselves during sex. It is a trait once deemed unique to bonobos and humans.
Twenty-five diverse vocalizations are acknowledged, a lot of which are utilized mainly for group interactions within dense vegetation. Sounds categorized as barks and grunts are often heard while travelling to know the location of individual troop members. They could also be employed in social interactions when discipline is needed.
Screams and roars signal alarm and are generated most frequently by silverbacks. Deep, beaches and rumbling sounds suggest satisfaction. These are often heard during foraging and sleeping periods.
Conflicts are settled continuously by displays and other dangerous behaviours that are aimed at intimidating without becoming physical. The formal charge display is personal to gorillas.
The entire process includes nine steps:
- Progressively accelerating hooting
- Symbolic feeding
- Increasing bipedally
- Tossing vegetation
- Chest-beating with cupped hands
- One leg kick
- Sideways running, two-legged to four-legged
- Slamming and ripping vegetation
- Banging the ground with palms to end display
Since gorilla got the attention of western society in the 1860s, it has been a recurring factor of various aspects of prominent tribe and media. For instance, gorillas have starred in monstrous fiction movies like King Kong and George of the Jungle.
Also, pulp fantasy tales such as Tarzan and Conan the Barbarian have featured gorillas as physical adversaries of the formal heroes.