Gorilla Reproduction

How Do Gorillas produce? Mating, Ovulation in Female Gorillas

Gorillas are mammals with a reproduction behavior similar to that of other mammals. Research is always done to learn about their life but most of the information currently available comes from individuals who have visited gorillas in their habitats particularly in the cases of mountain gorillas and western lowland gorillas

On their research about reproductive behavior, it has been found that all subspecies share many similarities to each other. Being similar to humans, female gorillas give birth to 1 offspring per delivery and it is not common to give birth to twins. The recurring reproductive cycle is 28/30-33 days, depending on the subspecies. After their first ovulatory cycle, they have to wait for a two-year period to breed an infant.

Females become sexually mature at the age of 10-12 years old, while males become sexually mature at 11-13 years. However, for the case of female gorillas, they can earlier reach sexual maturity years, even at 7-8 years old and can have their first ovulatory cycle even during their sixth year of life but they do not start breeding until they are ten years old or later. One of the most surprising facts is that after their first ovulatory cycle, they are unable to pro-create an infant for about two years.

For the next six months of the infant’s life, the mother has the responsibility of never letting it out of its sight.  The young gorilla spends two to three years suckling.  This is also the time that it interacts more with the other group members.  By the time that the infant is four years old, the male gorilla may separate from the mother, while the female gorilla stays in the group for a few more years.  Eventually she will also leave to find a mate.  Female gorillas may raise two or three young throughout her entire life.

Gorillas are polygamous animals. By nature, male gorillas can perceive the moment when a female is available to mate), but the external signs are not as evident as in female chimpanzees, which show a swelling in the genital region easy to note.

There is no a specific mating season so that they can mate during any time of the year. Females are on heat during 1 or 2 days a month, but before they start having sex partners they must be separated from their born troop and start searching for a “silverback” male from another group. Females are the ones who attract male gorillas with body movements: initially, slowly and leisurely they approach the “silverback” with uninterrupted eye contact while puckering their lips and then they have to assess the male response to take the next step. If the male courted do not react at her signal, she gets closer and can even touch him. If this still does not work, she hardly hit the ground in a final attempt to draw his attention once and for all. It is only the “silverback” leader has the right to mate with the females.

The saddle shaped areas of silver hair found on male gorilla’s back shows that a male has reached sexual maturity. Like human beards this distinctive fur helps to communicate to other gorillas in the troop which gorillas are male and mature. The dominant silverback has more than a few grey hairs to worry about. He makes decisions on behalf of the group, determines movement, mediates conflict, protects young gorillas from infanticide and defends against predators.

Pregnancy takes 8.5 months and there are typically 3 – 4 years between births. A mother may successfully raise 4–6 children during her lifetime of 30 – 40 years. Infant mortality is high about 30% kids die of various natural causes before the age of 6; experienced mothers tend to be more successful. Unexpectedly, habituated troops have higher growth rates than unhabituated troops for reasons that are unknown; medical supervision may be a factor.

At birth, baby gorillas weigh 1.5–2 kilograms. Newborns are dependent on their mothers until 5 months. They then ride on their mothers’ backs for 4 months before becoming independent at around one year. However, they stay with their mothers until they are about 3 years by which point they are fully weaned.