Lifecycle of Mountain gorillas – Gorilla Facts
Lifecycle of Mountain gorillas examines the elaborate processes and stages of growth from the time the gorilla is born to the time of death (conception, birth, growth, reproduction and death). Mountain gorillas have no specific breeding season (give birth at any time of the year) and their gestation period is 8.5 months.
Most offsprings in the gorilla family are fathered by the dominant silverback (the mature male that leads the family) and can father up to 30 children in a lifetime while the female gorilla can only have up to 6 offspring in a lifetime.
Female mountain gorillas become sexually active at 10 years old while the males reach sexual maturity at 13 years of age. After the 8.5 months pregnancy, one baby (sometimes twins) is born weighing 1.8-2 kilograms (4-4.4 pounds) and is still weak, helpless and dependent on the mother.
A female mountain gorilla gives birth after every four years but mortality rate of new born babies is 40%, hence an adult female will have only one surviving offspring after 6-8 years. It is because of the slow reproduction rate and low mortality rate that a female gorilla can give birth to 2-6 babies in a lifetime.
The infants learn to sit at 3 months and are carried until they are four months old. Babies start walking at 3-4 months and during this time, they are always carried by their mothers but in case she dies, it’s the silverbacks to carry them.
However, they learn to cling on their mother’s back from 4 months and will travel on the back until after weaning (three and a half years) but by three years old, they are independent although not yet mature. During infancy, the mountain gorillas are vulnerable to predators (especially leopards) and even silverbacks especially when the mother leaves the family to join another family or when another silverback takes over leadership of the family.
From 4-6 or 8 years, the mountain gorillas become juveniles and start becoming independent although not yet mature. During this time, sexual dimorphism becomes almost difficult since both males and females are of the same weight (over 60 kilograms), size, have thick black hairs on their backs and are of the same height (1.2 meters tall).
As mountain gorillas start approaching adulthood (young adults), females of 8-10 years stop growing taller while the males (12-15 years) continue adding weight until reaching 113-135 kilograms. The males still have black hairs on their backs hence the reason they are referred as “blackbacks”.
Adulthood is always the last stage on the lifecycle of mountain gorillas and during this stage, males develop silver-gray patch on their backs hence referred as “Silverbacks”. It’s easier to differentiate male gorillas from females during adulthood. The males also stop gaining weight with an average male weighing between 204 and 226 kilograms (450 and 500 pounds).