Summary
Mountain gorillas (Gorilla gorilla beringei) are the largest primate and one of the closest living relatives to humans. They have robust bodies with long arms and short legs. They walk quadrupedally, using their knuckles of their hands to help support some of their weight. Mountain gorillas are highly endangered species and can only be found in central Africa. Only about 650 mountain gorillas remain in this area with approximately 330 mountain gorillas living in the Virunga Volcano region of Rwanda, Uganda, and Zaire and another 320 living in the Bwinda Impenetrable Forest in Uganda. Mountain gorillas are mainly herbivorous animals that eat over 100 different species of plants.
Mountain gorillas live in home ranges that are an average of 8 km2. The home range does not remain constant due to the availability of food. They need a wide variety of food to satisfy their nutritional requirements. According to Dian Fossey (1974), the presence or absence of other groups is a very strong factor of the ranging patterns of the group. They also move around to avoid predation. Mountain gorillas have very few natural enemies. Humans are the main cause for their endangerment.
The social structure of the mountain gorillas consists of an alfa, silverback male, several mature females and their offspring, with an average size of 17 individuals. There are close relationships between the silverback and the females. This shows that the social bonds between the mature males and the females are strong. However, female-female relationships are uncommon. This is due to the fact that they are mostly unrelated since they tend to transfer from their parental group at a young age. Offsping have close relationships with the mother and the silverback male. Mountain gorillas are usually gentle animals, unless they feel like they are endangered. The majority of gorilla experts do not believe that a hierarchy exists in the females. Females may transfer, during inter-group encounters, to several groups throughout their lifetime.
Mountain gorillas exhibit a female defense polygnous mating system. The benefits of polgyny include that males can have access to more than one female, females can choose high quality males, and females are provided with more protection due to the presence of other females. However, polygyny also heightens competition between teh males and females and predators may be more attracted to the group. Relationships within a group are not based on resource defense polygny since the home ranges' of the gorillas overlap extensively. They are not considered promiscuous because they are very few mature males in each group.