Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Hominidae
Subfamily: Homininae
Tribe: Gorillini
Genus: Gorilla

There are two distinct species of gorilla, separated geographically by the inner Congo Basin in Central Africa, to the south of the River Congo.  Each species is divided in to two separate sub species:  Eastern gorillas are divided in to the Eastern lowland gorilla and Mountain gorilla; Western gorillas are divided into Western lowland gorillas and Cross River gorillas.  All four sub-species are endangered, three of them critically so. 
Gorillas are perhaps the most genetically similar species to human beings as 98% of gorilla DNA is identical to human DNA.  They live in family groups of between eight and 11 individuals, consisting of a dominant silverback male, three or four adult females and their offspring.  The adults spend most of their day eating and resting, while the youngsters enjoy climbing and playing.  Their diet consists of fruit, shoots and leaves. The rain forest environment in which they live is so abundant with these staples that gorillas are never too far away from their next meal. 

Mountain Gorillas (Gorilla beringei beringei):

Only about 720 Mountain Gorillas are known to exist and their habitat is disappearing at an alarming rate.  Most of the Mountain Gorillas live in war torn regions like Rwanda and the Democratic Republic of Congo.  In these areas poverty-stricken communities are taking more and more refuge in the lush forest areas where the gorillas live, forcing the gorillas into smaller pockets of the forest.  Also, there are increasing reports in Rwanda and DRC of mass murders of gorillas by soldiers. 

Eastern Lowland Gorillas (Gorillla beringei grauri): 

With a known population of less than 3,000 individuals, the Eastern Lowland Gorillas are considered critically endangered.  Since they reside completely within the war torn DRC, these gorillas suffer from a constant threat of illegal poaching, casualties of war and loss of habitat due to illegal mining.  There is no real legally protected land for the Eastern Lowland Gorillas and unless this protection is put in place soon, they could disappear from the wild overnight. 

Mt Tshiaberimu Gorillas - These are currently considered to be Eastern Lowland Gorillas and only 20 of these gorillas are known to exist.  They are much smaller than any other sub-species of gorilla and may be re-classified as a distinct sub-species, Gorilla beringei rex-pymaeorum.  They live in a small isolated area of forest in the northern part of Virunga National Park in the DRC.  In 1996 there were so few individuals left of this type that they were in imminent danger of complete extinction.  Fortunately the Gorilla Organization was able to protect the region where these gorillas were found and 12 years latter there are now
20 healthy individuals.

Western Lowland Gorillas (Gorilla gorilla gorilla): 

The good news is, over 125,000 Western Lowland Gorillas have recently been discovered in the Republic of Congo and are living in a protected and mostly unpopulated (by humans) area of around 18,000 square miles.  But like all gorillas of the wild they are still under constant threat from humans.  Logging companies are building roads into gorilla territory and these roads make easy access for poachers hunting for the illegal bushmeat.  The more humans encroach on the gorillas' territory the more diseases will spread through the gorilla population.  Many of these diseases are fatal especially the ebola virus. 

Cross River Gorillas (Gorilla gorilla diehli): 

Unless the Mt. Tshiaberimu's are re-classified as a sub-species, the Cross River Gorillas are the most endangered of all the gorillas.  They exist in eight small isolated populations, separated by farmland and settlements in Nigeria and Cameroon.  Each day these settlements and farms eat away more of the gorillas' habitat, and illegal hunting of these gorillas goes largely unchecked.  In the 1960's war in Nigeria it was thought that the Cross River gorillas had been wiped out.  However, in the 1980's small numbers of the sub-species were rediscovered in Cameroon and later in small areas of Nigeria on the banks of the Cross River.  These gorillas are so elusive that very little is known about them.  

Gorillas are perhaps the most intelligent and socialized creatures other than humans.  They live in socially structured groups of loosely related individuals called 'troops'.  These troops have a chain of command, with a dominant adult male leader or 'silverback' as their commander. 

The silverback plays the role of father, husband, group leader and protector.  He will determine where the troop camps and when and where they will move to.  He governs the troop as a father will, disciplining the younger members of the troop and demanding respect at all times for the elders.  If challenged by a younger male or by a male from outside the troop, a silverback will scream, beat his chest, break branches, bare his teeth, then charge forward.    If the leader is killed by disease, accident, fighting or poachers, the group will split up, as the animals disperse to look for a new protective male.  Very occasionally, a group might be taken over in its entirety by another male.  

Troops will vary in size from 5 to 30 members and will usually consist of multiple adult females, a few sexually mature males, known as blackbacks, and several younger males and females from new borns to teenagers.  Males will start to leave their own troop when they are 11 to 12 years of age and travel alone or in small groups in search of another troop.  This behaviour is the gorillas' method of preventing inbreeding, and it is also one of the reasons that gorillas populations are in decline.  As gorilla territories become more fragmented it becomes harder for young adult males to roam between troops.  Many are killed by hunters and soldiers before they can be incorporated into a new troop.  

How big are gorillas?  Adult males range in height from 5 1/2 to 6 feet and weigh between 300 and 450 lbs.  Adult females are rarely over 4 1/2 feet tall and weigh between 150 and 200 lbs.  

In the wild gorillas have an average lifespan of around 35 years, in captivity they are living closer to 50 years.  

Genetically gorillas and humans are almost identical, with gorilla and human DNA matching at 98.4%, closer than any two other species.  It is this fact that has lead many evolutionists to believe that humans evolved from apes.  But, if humans 'evolved' from apes, why are there still apes?  This seems to be a question none of the scientist feel comfortable answering.

Did you know - Gorillas use tools, communicate with both body language and vocalizations, and have been documented as learning American Sign Language?

Keep visiting this page as we will add more Gorilla facts each month!