Mountain Gorillas Ecology: The word “gorilla” comes from the history of Hanno the Navigator, (c. 500 BC) a Carthaginian explorer on an expedition on the west African coast to the area that later became Sierra Leone. Members of the expedition encountered “savage people, the greater part of whom were women, whose bodies were hairy, and whom our interpreters called Gorillae”. The word was then later used as the species name, though it is unknown whether what these ancient Carthaginians encountered were truly gorillas, another species of ape or monkeys, or humans. BOOK NOW
The American physician and missionary Thomas Stoughton Savage and naturalist Jeffries Wyman first described the western gorilla (they called it Troglodytes gorilla) in 1847 from specimens obtained in Liberia. The name was derived from Ancient Greek Γόριλλαι (gorillai), meaning “tribe of hairy women”, described by Hanno.
Evolution and classification
The closest relatives of gorillas are the other two Homininae genera, chimpanzees and humans, all of them having diverged from a common ancestor about 7 million years ago. Human gene sequences differ only 1.6% on average from the sequences of corresponding gorilla genes, but there is further difference in how many copies each gene has. Until recently, gorillas were considered to be a single species, with three subspecies: the western lowland gorilla, the eastern lowland gorilla and the mountain gorilla. There is now agreement that there are two species, each with two subspecies. More recently, a third subspecies has been claimed to exist in one of the species. The separate species and subspecies developed from a single type of gorilla during the Ice Age, when their forest habitats shrank and became isolated from each other.
Physical characteristics
Gorillas move around by knuckle-walking, although they sometimes walk biped ally for short distances while carrying food or in defensive situations. Wild male gorillas weigh 135 to 195 kg (300 to 430 lb) while adult females usually weigh half as much as adult males at 70–115 kg (150–250 lb). Adult males are 1.5 to 1.8 m (4 ft 11 in to 5 ft 11 in) tall, with an arm span that stretches from 2.3 to 2.6 m (7 ft 7 in to 8 ft 6 in). Female gorillas are shorter, with smaller arm spans. Adult male gorillas are known as silverbacks due to the characteristic silver hair on their backs reaching to the hips. The tallest gorilla recorded was a 1.94 m (6 ft 4 in) silverback with an arm span of 2.7 m (8 ft 10 in), a chest of 1.98 m (6 ft 6 in), and a weight of 219 kg (483 lb), shot in Alimbongo, northern Kivu in May 1938. The heaviest gorilla recorded was a 1.83 m (6 ft 0 in) silverback shot in Ambam, Cameroon, which weighed 266 kilograms (586 lb). Males in captivity are noted to be capable of reaching weights up to 275 kg (606 lb). Gorilla facial structure is described as mandibular prognathism, that is, the mandible protrudes farther out than the maxilla. Adult males also have a prominent sagittal crest.
The eastern gorilla is more darkly colored than the western gorilla, with the mountain gorilla being the darkest of all. The mountain gorilla also has the thickest hair. The western lowland gorilla can be brown or grayish with a reddish forehead. In addition, gorillas that live in lowland forests are more slender and agile than the more bulky mountain gorillas. The eastern gorilla also has a longer face and broader chest than the western gorilla.
Studies have shown gorilla blood is not reactive to anti-A and anti-B monoclonal antibodies, which would, in humans, indicate type O blood. Due to novel sequences, though, it is different enough to not conform to the human ABO blood group system, into which the other great apes fit. Like humans, gorillas have individual finger prints. Their eye color is dark brown, framed by a black ring around the iris.
Mountain gorilla or the gorilla beringei. The mountain gorilla is considered to be largest yet the rarest among the gorilla types. The adult male mountain gorilla can weigh over 500 pounds or almost 227 kilograms! This gorilla subspecies has longer and darker hair because of the colder climate in its habitat which is on the mountain. This gorilla subspecies is more “handsome” compared to its lowland cousins. They are taller and gap on their middle nose is wider. Also, mountain gorillas don’t have pinkish hair patches on the head portion, unlike its lowland counterparts.
Distribution and habitat
Gorillas have a patchy distribution. The range of the two species is separated by the Congo River and its tributaries. The western gorilla lives in west central Africa, while the eastern gorilla lives in east central Africa. Between the species, and even within the species, gorillas live in a variety of habitats and elevations. Gorilla habitat ranges from montane forests to swamps. Eastern gorillas inhabit montane and submontane forests between 650 and 4,000 m (2,130 and 13,120 ft) above sea level. Mountain gorillas live in the montane forests at the higher ends of the elevation range, while eastern lowland gorillas live in submontane forests at the lower ends of the elevation range. In addition, eastern lowland gorillas live in montane bamboo forests, as well as lowland forests ranging from 600–3,308 m (1,969–10,853 ft) in elevation. Western gorillas live in both lowland swamp forests and montane forests, and elevations ranging from sea level to 1,600 m (5,200 ft). Western lowland gorillas live in swamp and lowland forests ranging up to 1,600 m (5,200 ft), and Cross River gorillas live in low-lying and submontane forests ranging from 150–1,600 m (490–5,250 ft).