The Mountain Gorilla (Gorilla beringei beringei) is one of two subspecies of Eastern Gorillas. There are two populations. One is only found in the Virunga volcanic mountains of Central Africa, within three national parks: Mgahinga, in south-west Uganda; Volcanoes, in north-west Rwanda; and Virunga, in the eastern Democratic Republic of Congo (DRC). The other is found in Uganda's Bwindi Impenetrable Forest. Some claim that the Bwindi population in Uganda is a third subspecies, although no formal taxonomic description has been published. -------------------------------------- A census taken in 2003 has shown a 17% increase in population size since 1989. There are now a total of 380 gorillas in 30 social groups in the Virungas and a total of about 320 in Bwindi. However, the Mountain Gorilla continues to be considered critically endangered on the IUCN Red List of Endangered Species. It faces an extremely high risk of extinction in the wild due to habitat loss, poaching, human disease, and war. The Virungas population became further threatened on September 3, 2007 due to an outbreak of violence in Virunga National Park between rebels loyal to Laurent Nkunda and DRC government forces. Rangers were forced to flee, leaving the gorillas undefended, and the fate of the estimated 100 gorillas on the Congo side of the border remains unknown. All in all there are only around 700 Mountain Gorillas left.------------------------------Severe aggression is rare in stable groups, but when two Mountain Gorilla groups meet, the two silverbacks can sometimes engage in a fight to the death, using their canines to cause deep, gaping injuries. For this reason, conflicts are most often resolved by displays and other threat behaviors that are intended to intimidate without becoming physical. The ritualized charge display is unique to gorillas. The entire sequence has nine steps: (1) progressively quickening hooting, (2) symbolic feeding, (3) rising bipedally, (4) throwing vegetation, (5) chest-beating with cupped hands, (6) one leg kick, (7) sideways running, two-legged to four-legged, (8) slapping and tearing vegetation, and (9) thumping the ground with palms to end display.---------------The midday rest period is an important time for establishing and reinforcing relationships within the group. Mutual grooming reinforces social bonds, and helps keep hair free from dirt and parasites. It is not as common among gorillas as in other primates, although females groom their offspring regularly. Young gorillas play often and are more arboreal than the large adults. Playing helps them learn how to communicate and behave within the group. Activities include wrestling, chasing and somersaults. The silverback and his females tolerate and even participate if encouraged.--------------------Twenty-five distinct vocalizations are recognized, many of which are used primarily for group communication within dense vegetation. Sounds classified as grunts and barks are heard most frequently while traveling, and indicate the whereabouts of individual group members.They may also be used during social interactions when discipline is required. Screams and roars signal alarm or warning, and are produced most often by silverbacks. Deep, rumbling belches suggest contentment and are heard frequently during feeding and resting periods. They are the most common form of intra-group communication.-----------------------For reasons unknown, Mountain Gorillas that have been studied appear to be naturally afraid of certain reptiles. Infants, whose natural behavior is to chase anything that moves, will go out of their way to avoid chameleons and caterpillars. Koko, the gorilla trained in sign language, is afraid of crocodiles and alligators, even though she was born in captivity and has never seen them. They are also afraid of water and will cross streams only if they can do so without getting wet (ie. crossing over fallen logs). Dian Fossey observed and noted the Mountain Gorilla's obvious dislike of rain, as well.