Gorilla Experience:  The mountain gorilla (Gorilla beringei beringei) is generally one of the two subspecies of the eastern gorilla. Besides, it is listed as critically endangered by the International Union for the Conservation of Nature (IUCN).

Gorilla Facts

Physical description

The fur of the  gorillas is often thicker and longer than that of other gorilla species which enables them to live in colder temperatures. In addition, adult males are called silverbacks because of a saddle of gray hair which develops on their backs with age. However, the hair on their backs is shorter than on most other body parts and their arm hair long. Gorillas can be identified by nose prints unique to each individual. Males have a weight of 195 kg upright standing with a height of 150 cm and usually weigh twice as much as the females. Furthermore, adult males have more pronounced bony crests on the top and back of their skulls.

As a matter of fact, the mountain gorilla is most active between 6:00 am and 6:00 pm. Many of these hours are spent eating as large quantities of food are needed to sustain its massive bulk. It basically forages in early morning, rests during the late morning and around midday. However, in the afternoon it forages again before resting at night. More so, each gorilla builds a nest from surrounding vegetation to sleep in and constructing a new one every evening.

Only infants sleep in the same nest as their mothers. Gorillas 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. Like all great apes other than humans, its arms are longer than its legs. Surprisingly, it moves by knuckle-walking, supporting its weight on the backs of its curved fingers rather than its palms.

Habitat and ecology

The mountain gorilla generally inhabits the Albertine Rift montane cloud forests and of the Virunga volcanoes. Additionally, 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 as well as berries. For that reason, it travels to the bamboo forests during the few months of the year when fresh shoots are available. The mountain gorilla is primarily herbivore.  Majority of its diet is composed of the leaves, shoots as well as stems. It also feeds on roots (3.3%), flowers (2.3%), and fruit (1.7%), as well as small invertebrates (0.1%). As a result, adult males can eat up to 34 kilograms of vegetation a day. On the other hand, a female can eat as much as 18 kilograms.

Behavior

The mountain gorilla is highly social and lives in relatively stable. More so, cohesive groups are held together by long-term bonds between adult males and females. The dominant silverback generally determines the movements of the group, leading it to appropriate feeding sites throughout the year. He also mediates conflicts within the group and protects it from external threats. Furthermore, when the group is attacked, the silverback will protect them even at the cost of his own life.

More silverback roles

He is also the center of attention during rest sessions. In addition. young gorillas frequently stay close to him and include him in their games. However, if a mother dies or leaves the group, the silverback is usually the one who looks after her abandoned offspring. On the other hand, when the silverback dies, the family group may be disrupted.  When a new silverback joins the family group, he may kill all of the infants of the dead silverback.

Social structure

A typical group consists of firstly, one dominant silverback, who is the group’s undisputed leader. Secondly, another subordinate silverback (usually a younger brother, half-brother, or even an adult son of the dominant silverback). Thirdly, one or two black backs who act as sentries. Then, three to four sexually mature females who are ordinarily bonded to the dominant silverback. Lastly, from three to six juveniles and infants.

Males leave when they are about 11 years old and often the separation process is slow. However, they spend more and more time on the edge of the group until they leave altogether. Females typically emigrate when they are about 8 years old. Either transferring directly to an established group or beginning a new one with a lone male. Besides, females often transfer to a new group several times before they settle down with a certain silverback male.

Affiliation

The midday rest period is an important time for establishing and reinforcing relationships within the group. Mutual grooming also reinforces social bonds and helps keep hair free from dirt and parasites. In addition, young gorillas play often and this helps them learn how to communicate and behave within the group. Activities include; wrestling, chasing, as well as somersaults. The silverback and his females tolerate and even participate if encouraged.

Fears

For reasons unknown, mountain gorillas that have been studied appear to be naturally afraid of certain reptiles and insects. They are also afraid of water and will cross streams only if they can do so without getting wet.

Vocalization

Sounds classified as grunts and barks are heard most frequently while traveling and indicate the whereabouts of individual group members. However, they may also be used during social interactions when discipline is required. On the other hand, screams and roars are used for alarm or warning and are produced most often by silverbacks.

Aggression

Although strong and powerful, the mountain gorillas are generally gentle and very shy. Severe aggression is rare in stable groups. However, when two groups meet, the two silverbacks can sometimes engage in a fight to death.

Conservation

Conservation efforts have led to an increase in overall population of the mountain gorilla in the Virungas and at Bwindi. Habituated gorillas are however more closely guarded by field staff. Additionally, they receive veterinary treatment. Nonetheless, researchers recommended that some gorillas remain unhabituated as a bet-hedging strategy against the risk of human pathogens being transmitted throughout the population. Despite their recent population growth, the mountain gorilla remains threatened.

Habitat loss

This is one of the most severe threats to gorilla populations. Furthermore, the forests where mountain gorillas live are surrounded by rapidly increasing human settlement. This however leads to the reduction of the genetic diversity for each group. Through shifting (slash-and-burn) agriculture, pastoral expansion and logging, villages in forest zones cause fragmentation and degradation of habitat. The resulting deforestation confines the gorillas to isolated deserts. In addition, the impact of habitat loss extends beyond the reduction of suitable living space for gorillas.

Poaching 

Mountain gorillas are not usually hunted for bush meat. But are frequently killed by traps and snares intended for other animals. They have also been killed for their heads, hands as well as feet, which are sold to collectors. Additionally, infants are sold to zoos, researchers, and people who want them as pets. The abduction of infants generally involves the loss of at least one adult. As a result, members of a group will fight to the death to protect their young

Disease

Groups subjected to regular visits from tourists and locals are at a continued risk of disease cross-transmission. Meanwhile, attempts to enforce a rule that humans and gorillas be separated by a distance of 7 metres to prevent diseases.