The Mountain Gorilla is one of the two subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 of the Eastern Gorilla

Eastern Gorilla

The eastern gorilla is a species of the genus Gorilla and the largest living primate. At present, the species is subdivided into two subspecies. The eastern lowland gorilla is the most populous, at about 5,000 individuals. The mountain gorilla has only about 700 individuals...

. There are two populations. One is found in the Virunga volcanic mountains

Virunga Mountains

The Virunga Mountains are a chain of volcanoes in East Africa, along the northern border of Rwanda, the Democratic Republic of the Congo and Uganda. The mountain range is a branch of the Albertine Rift, a part of the Great Rift Valley. They are located between Lake Edward and Lake Kivu...

 of Central Africa

Central Africa

Central Africa is a core region of the African continent which includes Burundi, the Central African Republic, Chad, the Democratic Republic of the Congo, and Rwanda....

, within three National Park

National park

A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or owns. Although individual nations designate their own national parks differently A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or...

s: Mgahinga

Mgahinga Gorilla National Park

Mgahinga Gorilla National Park is a national park in the far south-west of Uganda near the town of Kisoro.-Location:The park is located in the Virunga Mountains and is contiguous with the Volcanoes National Park in Rwanda and the Virunga National Park in the Democratic Republic of the Congo...

, in south-west Uganda

Uganda

Uganda , officially the Republic of Uganda, is a landlocked country in East Africa. Uganda is also known as the "Pearl of Africa". It is bordered on the east by Kenya, on the north by South Sudan, on the west by the Democratic Republic of the Congo, on the southwest by Rwanda, and on the south by...

; Volcanoes

Volcanoes National Park

For the park in Hawaii, see Hawaii Volcanoes National Park.Volcanoes National Park lies in northwestern Rwanda and borders Virunga National Park in the Democratic Republic of Congo and Mgahinga Gorilla National Park in Uganda. The national park is known as a haven for the mountain gorilla...

, in north-west Rwanda

Rwanda

Rwanda or , officially the Republic of Rwanda , is a country in central and eastern Africa with a population of approximately 11.4 million . Rwanda is located a few degrees south of the Equator, and is bordered by Uganda, Tanzania, Burundi and the Democratic Republic of the Congo...

; and Virunga

Virunga National Park

The Virunga National Park , formerly named Albert National Park, is a 7800 square km National Park that stretches from the Virunga Mountains in the South, to the Rwenzori Mountains in the North, in the eastern Democratic Republic of Congo, bordering Volcanoes National Park in Rwanda and Rwenzori...

 in the eastern Democratic Republic of Congo (DRC). The other is found in Uganda's Bwindi Impenetrable National Park

Bwindi Impenetrable National Park

Bwindi Impenetrable National Park is located in southwestern Uganda in East Africa. The park is part of the Bwindi Impenetrable Forest, and is situated along the Democratic Republic of Congo border next to the Virunga National Park and on the edge of the western Great Rift Valley...

. Some primatologists say that the Bwindi population in Uganda may be a separate subspecies, though no description has been finished.
As of Spring 2010, the estimated total number of Mountain Gorillas worldwide is 790.

Description

The fur of the Mountain Gorilla, often thicker and longer than that of other Gorilla species, enables them to live in colder temperatures. Gorillas can be identified by nose prints unique to each individual. Males usually weigh twice as much as the females, and this subspecies is on average the largest of all gorillas. Adult males have more pronounced bony crests on the top and back of their skulls, giving their heads a more conical shape. These crests anchor the powerful masseter muscle

Masseter muscle

In human anatomy, the masseter is one of the muscles of mastication.In the animal kingdom, it is particularly powerful in herbivores to facilitate chewing of plant matter.-Origin and insertion of the two heads:...

s, which attach to the lower jaw (mandible). Adult females also have these crests, but they are less pronounced. Like all gorillas they feature dark brown eyes framed by a black ring around the iris.

Adult males are called silverbacks because a saddle of gray or silver-colored hair develops on their backs with age. The hair on their backs is shorter than on most other body parts, and their arm hair is especially long. Fully erect, males reach 1.9 m (6.2 ft) in height, with an arm span of 2.3 m (7.5 ft) and weigh 220 kg (485 lb). The tallest silverback recorded was a 1.94 metre individual shot in Alimbongo, northern Kivu

Kivu

Kivu was the name for a large "Region" in the Democratic Republic of Congo under the rule of Mobutu Sese Seko that bordered Lake Kivu. It included three "Sub-Regions" : Nord-Kivu, Sud-Kivu and Maniema, corresponding to the three current provinces created in 1986...

 in May 1938. There's an unconfirmed record of another individual, shot in 1932, that was 2.06 m (6 ft 9 in) tall. The heaviest was a 1.83 m (6 ft) silverback shot in Ambam

Ambam

Ambam is a town and commune in South Province of Cameroon on the border with Equatorial Guinea and Gabon. This frontier town is located approximately 220 km from Yaounde and as of 2005 had a population of 1,596. Traditionally, it has traded with its neighbouring countries across the border...

, Cameroon

Cameroon

Cameroon, officially the Republic of Cameroon , is a country in west Central Africa. It is bordered by Nigeria to the west; Chad to the northeast; the Central African Republic to the east; and Equatorial Guinea, Gabon, and the Republic of the Congo to the south. Cameroon's coastline lies on the...

 which weighed about 266 kg (586.4 lb).

The Mountain Gorilla is primarily terrestrial

Terrestrial animal

Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...

 and quadrupedal. However, it will climb into fruiting trees if the branches can carry its weight, and it is capable of running bipedally up to 6 m (20 ft). Like all great apes other than humans, its arms are longer than its legs. It moves by knuckle-walking (like the Common Chimpanzee

Common Chimpanzee

The common chimpanzee , also known as the robust chimpanzee, is a great ape. Colloquially, the common chimpanzee is often called the chimpanzee , though technically this term refers to both species in the genus Pan: the common chimpanzee and the closely related bonobo, formerly called the pygmy...

, but unlike the Bonobo

Bonobo

The bonobo , Pan paniscus, previously called the pygmy chimpanzee and less often, the dwarf or gracile chimpanzee, is a great ape and one of the two species making up the genus Pan. The other species in genus Pan is Pan troglodytes, or the common chimpanzee...

 and both orangutan

Orangutan

Orangutans are the only exclusively Asian genus of extant great ape. The largest living arboreal animals, they have proportionally longer arms than the other, more terrestrial, great apes. They are among the most intelligent primates and use a variety of sophisticated tools, also making sleeping...

 species), supporting its weight on the backs of its curved fingers rather than its palms.

The Mountain Gorilla is diurnal

Diurnal animal

Diurnality is a plant or animal behavior characterized by activity during the day and sleeping at night.-In animals:Animals that are not diurnal might be nocturnal or crepuscular . Many animal species are diurnal, including many mammals, insects, reptiles and birds...

, most active between 6:00 a.m. and 6:00 p.m. Many of these hours are spent eating, as large quantities of food are needed to sustain its massive bulk. It forages

Foraging

- Definitions and significance of foraging behavior :Foraging is the act of searching for and exploiting food resources. It affects an animal's fitness because it plays an important role in an animal's ability to survive and reproduce...

 in early morning, rests during the late morning and around midday, and in the afternoon it forages again before resting at night. Each gorilla builds a nest from surrounding vegetation to sleep in, constructing a new one every evening. Only infants sleep in the same nest as their mothers. They leave their sleeping sites when the sun rises at around 6 am, except when it is cold and overcast; then they often stay longer in their nests.

Habitat and diet

The Mountain Gorilla inhabits the Albertine Rift

Albertine Rift montane forests

The Albertine Rift montane forests ecoregion, of the Tropical moist broadleaf forest Biome, are in the heart of Afromontane tropical Africa.-Location and description:...

 montane cloud forest

Cloud forest

A cloud forest, also called a fog forest, is a generally tropical or subtropical evergreen montane moist forest characterized by a persistent, frequent or seasonal low-level cloud cover, usually at the canopy level. Cloud forests often exhibit an abundance of mosses covering the ground and...

s and of the Virunga Volcanoes

Virunga Mountains

The Virunga Mountains are a chain of volcanoes in East Africa, along the northern border of Rwanda, the Democratic Republic of the Congo and Uganda. The mountain range is a branch of the Albertine Rift, a part of the Great Rift Valley. They are located between Lake Edward and Lake Kivu...

, ranging in altitude from 2200 –. Most are found on the slopes of three of the dormant volcanoes: Karisimbi

Mount Karisimbi

Mount Karisimbi is an inactive volcano in the Virunga Mountains on the border between Rwanda and the Democratic Republic of Congo. At , Karisimbi is the highest of the eight major mountains of the mountain range, which is a part of the East African Rift Valley...

, Mikeno

Mount Mikeno

Mount Mikeno is a volcanic mountain located in the Democratic Republic of the Congo section of the Virunga Mountains along with Mount Nyiragongo, Mount Nyamuragira, Mount Karisimbi, and Mount Bisoke...

, and Visoke. The vegetation is very dense at the bottom of the mountains, becoming more sparse at higher elevations, and the forests where the Mountain Gorilla lives are often cloudy, misty and cold.

The Mountain Gorilla is primarily a herbivore; the majority of its diet is composed of the leaves, shoots and stems (85.8%) of 142 plant species. It also feeds on bark (6.9%), roots (3.3%), flowers (2.3%), and fruit (1.7%), as well as small invertebrates. (0.1%). Adult males can eat up to 34 kilograms (75 lb) of vegetation a day, while a female can eat as much as 18 kilograms (39.7 lb).

The home range size (the area used by one group of gorillas during one year) is influenced by availability of food sources and usually includes several vegetation zones. George Schaller

George Schaller

George Beals Schaller is an American mammalogist, naturalist, conservationist and author. Schaller is recognized by many as the world's preeminent field biologist, studying wildlife throughout Africa, Asia and South America. Born in Berlin, Schaller grew up in Germany, but moved to Missouri as a...

 identified ten distinct zones, including: the bamboo forests at 2200 –; the Hagenia

Hagenia

Hagenia abyssinica is a species of flowering plant native to the high-elevation Afromontane regions of central and eastern Africa. It also has a disjunct distribution in the high mountains of East Africa from Sudan and Ethiopia in the north, through Kenya, Uganda, Rwanda, Burundi, Democratic...

 forests at 2800 –; and the giant senecio zone at 3400 –. The Mountain Gorilla spends most of its time in the Hagenia forests, where gallium vines are found year-round. All parts of this vine are consumed: leaves, stems, flowers, and berries. It travels to the bamboo

Bamboo

Bamboo is a group of perennial evergreens in the true grass family Poaceae, subfamily Bambusoideae, tribe Bambuseae. Giant bamboos are the largest members of the grass family....

 forests during the few months of the year fresh shoots are available, and it climbs into subalpine

Subalpine

The subalpine zone is the biotic zone immediately below tree line around the world. Species that occur in this zone depend on the location of the zone on the Earth, for example, Snow Gum in Australia, or Subalpine Larch, Mountain Hemlock and Subalpine Fir in western North America.Trees in the...

 regions to eat the soft centers of giant senecio trees.

Social structure

The Mountain Gorilla is highly social

Social

The term social refers to a characteristic of living organisms...

, and lives in relatively stable, cohesive groups held together by long-term bonds between adult males and females. Relationships among females are relatively weak. These groups are nonterritorial; the silverback generally defends his group rather than his territory. In the Virunga Mountain Gorillas, the average length of tenure for a dominant silverback is 4.7 years.
61% of groups are composed of one adult male and a number of females and 36% contain more than one adult male. The remaining gorillas are either lone males or exclusively male groups, usually made up of one mature male and a few younger males. Group sizes vary from five to thirty, with an average of ten individuals. A typical group contains: one dominant silverback, who is the group's undisputed leader; another subordinate silverback (usually a younger brother, half-brother, or even an adult son of the dominant silverback); one or two blackbacks, who act as sentries; three to four sexually mature females, who are ordinarily bonded to the dominant silverback for life; and from three to six juveniles and infants.

Most males, and about 60% of females, leave their natal group. Males leave when they are about 11 years old, and often the separation process is slow: they spend more and more time on the edge of the group until they leave altogether.

The dominant silverback generally determines the movements of the group, leading it to appropriate feeding sites throughout the year. He also mediates

Mediation

Mediation, as used in law, is a form of alternative dispute resolution , a way of resolving disputes between two or more parties. A third party, the mediator, assists the parties to negotiate their own settlement...

 conflicts within the group and protects it from external threats. When the group is attacked by humans, leopards, or other gorillas, the silverback will protect them even at the cost of his own life. He is the center of attention during rest sessions, and young animals frequently stay close to him and include him in their games. If a mother dies or leaves the group, the silverback is usually the one who looks after her abandoned offspring, even allowing them to sleep in his nest. Experienced silverbacks are capable of removing poachers' snares from the hands or feet of their group members.

When the dominant silverback dies or is killed by disease, accident, or poachers, the family group may be severely disrupted. Unless he leaves behind a male descendant capable of taking over his position, the group will either split up or be taken over in its entirety by an unrelated male. When a new silverback takes control of a family group, he may kill all of the infants of the dead silverback. This practice of infanticide is an effective reproductive strategy, in that the newly acquired females are then able to conceive the new male's offspring. Infanticide

Infanticide

Infanticide or infant homicide is the killing of a human infant. Neonaticide, a killing within 24 hours of a baby's birth, is most commonly done by the mother.In many past societies, certain forms of infanticide were considered permissible...

 has not been observed in stable groups.

Aggression

Although strong and powerful, gorillas are generally gentle and shy. Severe aggression

Aggression

In psychology, as well as other social and behavioral sciences, aggression refers to behavior between members of the same species that is intended to cause humiliation, pain, or harm. Ferguson and Beaver defined aggressive behavior as "Behavior which is intended to increase the social dominance of...

 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. 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.

Affiliation

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 somersault, and just playing around. The silverback and his females tolerate and even participate if encouraged.

Vocalization

Twenty-five distinct vocalization

Animal communication

Animal communication is any behavior on the part of one animal that has an effect on the current or future behaviour of another animal. The study of animal communication, is sometimes called Zoosemiotics has played an important part in the...

s 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 intragroup communication.

Fears

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

Koko (gorilla)

Koko is a female western lowland gorilla who, according to Francine "Penny" Patterson, is able to understand more than 1,000 signs based on American Sign Language, and understand approximately 2,000 words of spoken English....

, the western lowland 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 (i.e. crossing over fallen logs). Dian Fossey

Dian Fossey

Dian Fossey was an American zoologist who undertook an extensive study of gorilla groups over a period of 18 years. She studied them daily in the mountain forests of Rwanda, initially encouraged to work there by famous anthropologist Louis Leakey...

 observed and noted the Mountain Gorilla's obvious dislike of rain, as well.

Physical Strength

Male Silverback Gorillas are about 10 times stronger than the biggest American football players.

Research

In October 1902, Captain Robert von Beringe (1865–1940) shot two large apes during an expedition to establish the boundaries of German East Africa

German East Africa

German East Africa was a German colony in East Africa, which included what are now :Burundi, :Rwanda and Tanganyika . Its area was , nearly three times the size of Germany today....

. One of the apes was recovered and sent to the Zoological Museum in Berlin

Berlin

Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...

, where Professor Paul Matschie

Paul Matschie

Paul Matschie was a German zoologist. He worked at the Zoological Museum in Berlin....

 (1861–1926) classified the animal as a new form of gorilla and named it Gorilla beringei after the man who discovered it. In 1925 Carl Akeley

Carl Akeley

Carl Ethan Akeley was a taxidermist, sculptor, biologist, conservationist, inventor, and nature photographer, noted for his contributions to American museums, most notably to the Field Museum of Natural History and the American Museum of Natural History...

, a hunter from the American Museum of Natural History

American Museum of Natural History

The American Museum of Natural History , located on the Upper West Side of Manhattan in New York City, United States, is one of the largest and most celebrated museums in the world...

 who wished to study the gorillas, convinced Albert I of Belgium

Albert I of Belgium

Albert I reigned as King of the Belgians from 1909 until 1934.-Early life:Born Albert Léopold Clément Marie Meinrad in Brussels, he was the fifth child and second son of Prince Philippe, Count of Flanders, and his wife, Princess Marie of Hohenzollern-Sigmaringen...

 to establish the Albert National Park to protect the animals of the Virunga mountains.

George Schaller

George Schaller

George Beals Schaller is an American mammalogist, naturalist, conservationist and author. Schaller is recognized by many as the world's preeminent field biologist, studying wildlife throughout Africa, Asia and South America. Born in Berlin, Schaller grew up in Germany, but moved to Missouri as a...

 began his 20 month observation of the Mountain Gorillas in 1959, subsequently publishing two books: The Mountain Gorilla and The Year of the Gorilla. Little was known about the life of the Mountain Gorilla before his research, which described its social organization, life history, and ecology. Following Schaller, Dian Fossey

Dian Fossey

Dian Fossey was an American zoologist who undertook an extensive study of gorilla groups over a period of 18 years. She studied them daily in the mountain forests of Rwanda, initially encouraged to work there by famous anthropologist Louis Leakey...

 began what would become a 13 year study in 1967. Fossey made new observations, completed the first accurate census, and established active conservation

Conservation biology

Conservation biology is the scientific study of the nature and status of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction...

 practices, such as anti-poaching patrols. The Digit Fund, which Dian Fossey started, continued her work and was later renamed the Dian Fossey Gorilla Fund International. The Fund's Karisoke Research Center monitors and protects the mountain gorillas of the Virungas. A census in 2004 showed a population of 380, most of it in the Karisoke sector and a significant increase since the time of Fossey's last count.

In April 2007 it was announced that a census of the Mountain Gorillas in Uganda's Bwindi Impenetrable National Park

Bwindi Impenetrable National Park

Bwindi Impenetrable National Park is located in southwestern Uganda in East Africa. The park is part of the Bwindi Impenetrable Forest, and is situated along the Democratic Republic of Congo border next to the Virunga National Park and on the edge of the western Great Rift Valley...

 had recorded a 6% increase in population since a census in 2002.

In December 2010 the official website of Virunga National Park announced that "the number of Mountain Gorillas living in the tri-national forested area of which Virunga forms a part, has increased by 26.3% over the last seven years - an average growth rate of 3.7% per annum." Together with the Bwindi population the estimated total number is just 790 individuals, with 4 of them being in care of the Senkwekwe Centre orphanage in the DR of Congo.

Conservation

Conservation efforts have led to an apparent increase in overall population of the Mountain gorilla (Gorilla beringei beringei). As noted above, a 2010 census announced a 26.3% increase in the Virunga population size between 2003 to 2010. An estimated 480 mountain gorillas now inhabit that region. The overall sub-population is now believed to be approximately 790.

The 2003 census estimated the gorilla Virunga sub population to be 380 individuals; this means there was a 17 % increase in the total population since 1989 when there were 320 individuals The increased numbers revealed in this census should be viewed with caution, because nearly all the increase can be attributed to one research area that is relatively well protected and believed to be good gorilla habitat. In fact other sectors were known to experience a decline.

The 2006 census of the Bwindi subpopulation revealed an increase to 340 gorillas, representing a 6% increase in total population size since 2002 and a 12% increase since 1997 from 320 individuals. A contradictory census in 2006 that combined genetic analysis of the entire population with traditional census methods revealed that there were only approximately 300 individuals in Bwindi

The discrepancies discussed above highlight the difficulty in relying on demographic data alone as it can be misleading. Despite some success, G. b. beringei remains threatened.

Mountain gorillas (Gorilla beringei beringei) are listed as Endangered by the International Union for Conservation of Nature Red List of Threatened Species (also known as the IUCN Red List or Red Data List). Endangered means the maximum population reduction over a three-generation (i.e. 60-year) period from the 1970s to 2030 is suspected to exceed 50%, hence qualifying this species for Endangered under criterion A4.

Threats

As with any flora and fauna, the decline of a population can usually be attributed to anthropogenic factors. Pollution, habitat destruction and fragmentation, over harvesting (in the form of illegal poaching), agriculture, and the introduction of diseases are some of the usual suspects; the Mountain gorilla suffers from all of these. All of the aforementioned are due to the most significant threat to gorilla survival; human population growth

Poaching: Mountain Gorillas are not usually hunted for bushmeat

Bushmeat

Bushmeat initially referred to the hunting of wild animals in West and Central Africa and is a calque from the French viande de brousse. Today the term is commonly used for meat of terrestrial wild animals, killed for subsistence or commercial purposes throughout the humid tropics of the Americas,...

, but they are frequently maimed or killed by traps and snares intended for other animals. They have been killed for their heads, hands, and feet, which are sold to collectors. Infants are sold to zoos, researchers, and people who want them as pets. The abduction

Kidnapping

In criminal law, kidnapping is the taking away or transportation of a person against that person's will, usually to hold the person in false imprisonment, a confinement without legal authority...

 of infants generally involves the loss of at least one adult, as members of a group will fight to the death to protect their young. The Virunga Gorillas are particularly susceptible to animal trafficking for the illegal pet trade. With young gorillas worth from $1000 to $5000 on the black market, poachers seeking infant and juvenile specimens will kill and wound other members of the group in the process. Those of the group that survive often disband. One well documented case was that known as the ‘Taiping 4’. In this situation, a Malaysian Zoo received four wild-born infant gorillas from Nigeria at a cost of US$1.6 million using falsified export documents .
Poaching for meat is also particularly threatening in regions of political unrest. Most of the African great apes survive in areas of chronic insecurity, where there is a breakdown of law and order. The killing of mountain gorillas at Bikenge in Virunga National Park

Virunga National Park

The Virunga National Park , formerly named Albert National Park, is a 7800 square km National Park that stretches from the Virunga Mountains in the South, to the Rwenzori Mountains in the North, in the eastern Democratic Republic of Congo, bordering Volcanoes National Park in Rwanda and Rwenzori...

 in January 2007 was a well documented case.

Habitat loss: This is one the most severe threats to gorilla populations. The forests where Mountain Gorillas live are surrounded by rapidly increasing human settlement. Through shifting (slash-and-burn) agriculture, pastoral expansion and logging, villages in forest zones cause fragmentation and degradation of habitat. The late 1960s saw the Virunga Conservation Area (VCA) of Rwanda’s national park reduced by more than half of its original size to support the cultivation of Pyrethrum. This led to a massive reduction in mountain gorilla population numbers by the mid-1970s. The resulting deforestation confines the gorillas to isolated deserts. Some groups may raid crops for food, creating further animosity and retaliation.
The impact of habitat loss extends beyond the reduction of suitable living space for gorillas. As gorilla groups are increasingly geographically isolated from one another due to human settlements, the genetic diversity of each group is reduced. Some signs of inbreeding are already appearing in younger gorillas, including webbed hands and feet .

Disease: Despite the protection garnered from being located in National parks, the Mountain Gorilla is also at risk from people of a more well-meaning nature. Groups subjected to regular visits from tourists and locals are at a continued risk of disease cross-transmission (Lilly et al., 2002) - this is in spite of attempts to enforce a rule that humans and gorillas be separated by a distance of 7 metres at all times to prevent this
With a similar genetic makeup to humans and an immune system that has not evolved to cope with human disease, this poses a serious conservation threat. Indeed, according to some researchers, infectious diseases (predominantly respiratory) are responsible for about 20% of sudden deaths in mountain gorilla populations.
It is notable that with the implementation of a successful ecotourism program in which human-gorilla interaction was minimised, during the period of 1989-2000 four sub-populations in Rwanda experienced an increase of 76%. By contrast, seven of the commonly visited sub-populations in the Democratic Republic of Congo (DRC) saw a decline of almost 20% over only four years (1996–2000). From this, we can conclude that the negative impacts of ecotourism on gorilla health can be minimised if proper management is undertaken.

The risk of disease transmission is not limited to those of a human origin; pathogens from domestic animals and livestock through contaminated water are also a concern. Studies have found that water borne, gastrointestinal parasites such as Cryptosporidium sp., Microsporidia sp.,and Giardia sp. are genetically identical when found in livestock, humans, and Gorillas; particularly along theborder of the Bwindi Impenetrable Forest, Uganda . Another example of human induced disease is Tuberculosis; Kabagambe et al. found that as high as 11% of cattle in Rwanda suffered from this affliction.

War and civil unrest: Rwanda, Uganda and the Democratic Republic of Congo have been politically unstable and beleaguered by war and civil unrest over the last decades. Simulation modeling, Byers et al. (2003) has suggested that times of war and unrest have negative impacts on the habitat and populations of Mountain Gorillas. For example, events such as 1994’s Rwanda genocide would take place approximately every 30 years, with each event lasting for 10 years. Due to the increase in human encounters, aggressive and passive alike, this would result in a rise in mortality rates and a decrease in reproductive success.
More direct impacts from conflict can also be seen. Kanyamibwa notes that there were reports that mines were placed along trails in the Volcanos National Park, and that many gorillas were killed as a result. Pressure from habitat destruction in the form of logging also increased as refugees fled the cities and cut down trees for wood. During the Rwandan genocide, some poaching activity was also linked to the general breakdown of law and order and lack of any ramifications.

Conservation efforts

The main International Non-Government Organization involved in conservation of mountain gorillas is the International Gorilla Conservation Programme

International Gorilla Conservation Programme

The International Gorilla Conservation Programme was formed in 1991 to ensure that the critically endangered mountain gorillas are conserved in their habitat in the mountain forests of the Virunga Massif in Rwanda, Uganda and the Democratic Republic of the Congo.-Origins:The programme grew out of...

, which was established in 1991 as a joint effort of the African Wildlife Foundation

African Wildlife Foundation

The African Wildlife Foundation , founded in 1961 as the African Wildlife Leadership Foundation, is an international conservation organization that focuses on critically important landscapes in Africa....

, Fauna & Flora International and the World Wide Fund for Nature

World Wide Fund for Nature

The World Wide Fund for Nature is an international non-governmental organization working on issues regarding the conservation, research and restoration of the environment, formerly named the World Wildlife Fund, which remains its official name in Canada and the United States...

.
Conservation requires work at many levels, from local to international, and involves protection and law enforcement as well as research and education. Dian Fossey broke down conservation efforts into the following three categories:

Active conservation includes frequent patrols in wildlife areas to destroy poacher equipment and weapons, firm and prompt law enforcement, census counts in regions of breeding and ranging concentration, and strong safeguards for the limited habitat the animals occupy."

Theoretical conservation seeks to encourage growth in tourism by improving existing roads that circle the mountains, by renovating the park headquarters and tourists' lodging, and by the habituation of gorillas near the park boundaries for tourists to visit and photograph."

Community-based Community- based conservation management involves biodiversity protection by, for, and with the local community in practise this is applied in varying degrees. The process seeks equity between meeting the needs of the local population and preserving the protected areas and involves local people in decision making processes.

A collaborative management process has had some success in the Bwindi National Park. The forest was gazetted to National Park in 1991; this occurred with little community consultation and the new status prohibited local people from accessing resources within the park as well as reduced economic opportunities. Subsequently a number of forest fires were deliberately lit and threats were made to the gorillas. To counteract this, three schemes to provide benefits from existence of the forest communities and involve the local community in park management were developed. They included agreements allowing the controlled harvesting of resources in the park, receipt of some revenue from tourism and establishment of a trust fund partly for community development. Tension between people and park have been reduced and now there is more willingness to take part in gorilla protection. Surveys of community attitudes conducted by CARE show a steadily increasing proportion of the people in favour of the park. More than that there have been no cases of deliberate burning and the problem of snares in these areas has been reduced.
The introduction of ceremonies such as Kwita Izina (in 2005) has also had some impact in drawing attention to gorilla preservation and its importance to local communities.

While community-based conservation bears out individual analysis, there are significant overlaps between active and theoretical conservation and a discussion of the two as halves of a whole seems more constructive. For example, in 2002 Rwanda's national parks went through a restructuring process. The director of the IGCP, Eugene Rutagarama stated that “They got more rangers on better salaries, more radios, more patrol cars and better training in wildlife conservation. They also built more shelters in the park, from which rangers could protect the gorillas". The funding for these types of improvements usually comes from tourism - in 2008, approximately 20 000 tourists visited gorilla populations in Rwanda, generating around $8 million in revenue for the parks. In Uganda too, tourism is seen as a “high value activity that generates enough revenue to cover park management costs and contribute to the national budget of the Uganda Wildlife Authority." Furthermore, tourist visits which are conducted by park rangers also allow censuses of gorilla sub-populations to be undertaken concurrently.

In addition to tourism, other measures for conservation of the sub-population can be taken such as ensuring connecting corridors between isolated areas to make movement between them easier and safer.

Threat	Effect on Gorilla Population	Conservation Efforts
Poaching	Gorillas are maimed or killed by traps set for other animals. Abduction of infants for illegal selling to zoos and as pets. This often results in other adult gorillas being killed in the process.	Increased patrolling using armed guards in protected forest areas. Karisoke’s guards find and remove some 1,000 snares each year. Gorilla censuses to monitor gorilla population. Karisoke Research Centre runs a facility for young gorillas rescued from poachers.
Habitat loss	Rapidly expanding human settlements are removing the gorilla habitat. Fragmentation of forested areas has resulted in the isolation of gorilla groups from each other, reducing genetic diversity.	Expansion of areas of national park to protect habitat.
Disease	Regular contact of tourists with the gorillas allows transmission of diseases from humans to the gorillas. Domestic animals and livestock also contribute to disease transmission.	Requirement to stay at least 7 metres from gorillas at all times. Better management of ecotourism. More education for local communities to minimise impact of livestock.
War and unrest	Refugees removing trees to create settlements and farms. Increased use of gorillas for meat by displaced peoples. Gorillas can be killed by land mines placed along forest paths.
Local communities	Habitat removal. Lack of support for conservation efforts due to insufficient education and awareness amongst locals. Poverty encourages the use of slash and burn agriculture to grow food.	Karisoke Research centre has: Created Virunga biodiversity inventory and field guides, to support public education and ecotourism. Supplied primary school students with books and other materials. Run conservation programs for secondary schools. Provided biodiversity training for local park staff and conservation groups. Provide field courses and internships for Rwandan college students.

Evolution

The evolution of the mountain gorillas is traced back to the Eocene epoch (55-34 million years ago) when the earth’s climate was fluctuating between warm and cool conditions. These early mountain gorillas were descendants of ancestral monkeys and apes found in Africa and Arabia during the start of the Oligocene epoch (34-24 million years ago). The fossil record provides evidence of the hominoid primates (apes and humans belong to this group) found in east Africa about 18-22 million years ago. The fossil record of the area where mountain gorillas live is particularly poor and so its evolutionary history is not clear
It was about 9 million years ago that the group of primates that were to evolve into gorillas split from their common ancestor with humans and chimps; this is when the genus Gorilla emerged. It is not certain what this early relative of the gorilla was, but it is traced back to the early ape Proconsul africanus. Mountain gorillas have been isolated from Eastern lowland gorillas for about 400 000 years and these two taxa separated from their western counterparts approximately 2 million years ago Gorillas have been the subject of taxonomic debate.
There has been considerable and as yet unresolved debate over the classification of mountain gorillas. The genus was first referenced as Troglodytes in 1847, but renamed to Gorilla in 1852. It was not until 1967 that the taxonomist Colin Groves proposed that all gorillas be regarded as one species (Gorilla gorilla) with three sub-species Gorilla gorilla gorilla (western lowland gorilla), Gorilla gorilla graueri (lowland gorillas found west of the virungas) and Gorilla gorilla beringei (mountain gorillas including, Gorilla beringei found in the virungas and bwindi). In 2003 after a review they were divided into two species (Gorilla gorilla and Gorilla beringei) by The World Conservation Union (IUCN).

External links

• Mountain Gorilla Veterinary Project, a NGO that provides medical care to the gorillas
• Conservation Through Public Health, an Ugandan NGO working for mountain gorilla conservation
• Official website for Dian Fossey Gorilla Fund International
• National Geographic Channel
• African Wildlife Foundation, mountain gorillas
• ARKive images and movies of eastern gorilla
• The Official Website for Virunga National Park, DR Congo
• "Missing DR Congo gorillas 'dead'" by Mark Kinver, BBC News
  BBC News
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  , 17 August 2007
• Official Baby Gorilla Naming Ceremony site- in Rwanda
• The website about the Mountain Gorillas in Rwanda, with many pictures