Great apes, gorillas seem to have evolved from lesser apes nearly twenty million years ago. They are currently divided variously into species and subspecies, though four distinct subspecies seem to be somewhat agreed upon: Mountain Gorilla (Gorilla Beringei Beringei), Cross River Gorilla (Gorilla Gorilla Diehli), Western Lowland Gorilla (Gorilla Gorilla Gorilla) and Eastern Lowland Gorilla (Gorilla Beringei Graueri).
Physical features vary amongst subspecies with Mountain Gorillas being the largest and hairiest of the four. They also are the darkest in color. Lowland Gorillas have longer arms and lighter coloration, being in the range of brown to gray in case of the Western Lowland Gorilla. Males of the species are bigger with weight averaging around four hundred pounds, though larger individuals of over five hundred pounds have been recorded in the wild and more often in captivity. Height is between five and a half to six feet. Females are nearly half that size with an average body weight of two hundred pounds and height generally under five feet. Overall body structure is bulky in case of both genders and upper body is very well developed including wide chest and strong shoulders with long and powerful limbs. Gorillas have opposable thumbs and move on all fours in a form known as knuckle-walking. The have been documented to use tools like chimps in the wild. Head is big with a prominent sagittal crest and strong jaws, including well developed canines. Eyes are small and brown and nose is uniquely patterned like human finger prints.
Despite their display in certain films and media as aggressive, dangerous beasts, gorillas are totally harmless and calm animals. They live in small groups headed by an adult male ‘silverback’ gorilla, named after a saddle shaped pattern of silver hair on the back. Younger ‘blackback’ males at times support the leader who makes all the choices regarding foraging and eating. They live in tropical and subtropical forests in equatorial Africa, usually occupying limited ranges of a few square kilometers per tribe. They spend their day eating leaves, twigs, fruits, branches, shoots, bamboos and even insects. Silverback leads them to their daily place of feeding and also takes care to supervise and protects its tribe. In case an intruder threatens to invade the group’s space, silverbacks show aggression through roaring, beating of chest, breaking and throwing of bamboos and objects and charging. Though gorillas can climb trees, they spend most of their time on the ground. Every evening they prepare nests in which to spend their night. These nests are distinct and enable researchers to accurately predict the numbers of gorillas in a locality by simply counting of the nests.
Gorillas are seen in countries of Central and West Africa. Mountain Gorillas are seen at high altitudes in Democratic Republic of Congo, Rwanda and Uganda. Lowland Gorillas reside in Angola, Cameroon, Central African Republic, Equatorial Congo, Republic of Congo, Gabon and Democratic Republic of Congo. Unfortunately unstable political climate and the war like atmosphere of these parts has not been conductive towards the great apes in the past and as a result, gorillas exist in small pockets today on the map of Africa.
Maturity is reached in gorillas at nearly ten years of age. Females give birth after every three to four years, following a gestation period of near eight and a half months. Mothers look after the young for up to three to four years. As adulthood is reached, the young often move off to establish their own families. Silverbacks are older than twelve years.