Mountain Gorillas are social animals and they thrive in averagely stable and cooperative groups / families which are kept together by the long-term bonds between the mature females and males. The Mountain Gorillas are non territorial and the Silverback minds about defending the group other than the territory. About 61% of the Gorilla groups feature one (1) mature male and a range of females while the remaining section feature more than one.
Other Gorillas live as individual males or as secluded male groups with one mature male and then a few young males. The Mountain Gorilla group range from 5 – 30 individuals and a normal group features one main Silverback, other subordinate Silverback which can be the younger brother or an adult son, one (1) or two (2) black backs, 3 – 4 females which are sexually mature, 3 – 6 juveniles and the infants. Males and around 60% of the females tend to depart from their natal groups. Males can leave the group at around the age of eleven (11) years and the separation process takes long as they start with feeding on the edge of the group up to the time when they leave altogether. They can depart alone or many males after which they attract some females to go with them. The females tend to leave the group at the age of eight (8) years where they either join an established gorilla family or start a new one with a lone male. The movements of the Gorilla family are majorly determined by the Silverback which leads the group to various feeding sites all the year round. The Silverback also mediates conflicts within the group and ensures their protection from the external threats even at the cost of his own life. During the resting sessions, the Silverback is the centre of attention with the young gorillas playing around him and often including him in their games. The Silverback undertakes the care of baby gorilla in case of the mother’s death or departure from the group. The experienced Silverbacks can at times remove the snares from the hands or feet of the group members. In a situation where the Silverback losses his life, the gorilla group may face disruption unless there is a capable male that can ably take on his position.
Mountain Gorillas are notably gentle and shy despite their power and strength. Aggression is not common on stable Mountain Gorilla families but when two different gorilla groups meet, the Silverbacks can at times engage in a fight which can even result into death of either as they use their canines to inflict injuries. Many times, the conflicts are settled by displays among other threat behaviours which are aimed at intimidating to avoid physical confrontation. The charging among the Mountain Gorillas follows a range of nine (9) steps and these include; progressive quick hooting, symbolic feeding, bipedal rising, vegetation throwing, chest-beating with cupped hands, single leg kick, four-legged side way running, vegetation tearing and slapping and thumping the ground with palms
The resting period at midday is notably very significant for re-enforcing and establishing relationships amongst Mountain Gorilla groups. Activities like mutual grooming takes place where the members help one another to get rid of dirt and parasites in their hairs. The young gorillas play a lot during this period and games can include; chasing, wrestling and somersaults. The Silverback along with the adult females tolerate the games and can even participate if encouraged.
The Mountain Gorillas features a range of twenty five (25) vocalisations which are recognised and most of these are used in primarily group communication while in dense vegetation. The grunts and barks are often heard as the gorillas are on the move to indicate the whereabouts of each group member but they can as well be used during social interactions to restore discipline. The roars and the screams are used to signal warning or alarm and these are commonly produced by Silverbacks. The deep rumbling belches often demonstrate content in the group are often heard while feeding and in the resting periods.
Mountain Gorillas are recorded to be in fear of reptiles. The infants which tend to follow any moving object would avoid the caterpillars and chameleons. Mountain Gorillas are also noted to be afraid of water and if possible, they can try to cross streams without getting wet such as using fallen logs.
The Silverbacks (adult males) normally head the family. Silverbacks are typically more aggressive than other group members they are responsible for keeping the troop out of trouble (troop safety). The silverback makes all group decisions, is responsible for most of the calls, receives the dominant portion of food and can terminate troublesome behavior with just a look. A male must have an established home range and great strength to confront any rival before acquiring his own troop. Therefore, most silverbacks are usually introverted for about 4 years and turn 15 before acquiring a troop of their own.
Competition for adult females is high and will often result in aggressive interactions between a dominant and rival silverback who is looking to either start or expand a troop. Adult females are not bonded to one another and usually compete to groom and stay close to the silverback. Mothers are closely bonded to their offspring for the first three years of life.
Protection and Care
The dominant silverback is responsible for the protection and safety of the troop. In times of a threatening situation, the silverback will fiercely beat its chest, produce loud scowling vocalizations and a pungent odor, throw vegetation and charge at its opponent or intruder. This is done to give time to the rest of the troop to retreat to a safe distance. The male in charge keeps its dominant status by standing upright, pounding his chest and bellowing deep cries, and even throwing things to assert his dominance.