The attention given to a fertile/ovulating female by the silverback tends to arouse competition among females in the group. There have even been cases of pregnant females mating with the silverback to reduce the chances of other fertile females from conceiving. Female gorillas frequently use sex to gain the favor of the dominant silverback to stop him from mating with other females. Sex for competition and for leisure is also not unheard of in gorillas. It was thought that face to face sex was unique to bonobos and humans but some gorilla species (mountain and western lowland gorillas) have been observed having sex with the individuals looking directly at each other. The female appears to kneel down as the female completes the copulation process.

Actual mating occurs on the ground with the silverback on top of the smaller female. A study in 1982 found that a silverback’s aggression towards a particular female forced her to initiate the process of mating even when she wasn’t in estrus. If the female is hesitant or resistant, the silverback may charge and slap the female to give in. The dominant silverback can also initiate mating by approaching the female and touching her or making a display with a grunt. If the dominant male is too busy or doesn’t react after several attempts, she may be open to mating with other males in the group. Should the male not respond, she will attract his attention by slapping the ground as she reaches towards him. When a female gorilla is ready to mate, she will approach the dominant male slowly, make sustained eye contact and purse her lips. In most cases, it is the female who initiates the mating process as soon as she ready. The moment when a female gorilla is ready to mate is not evident physically like it is in chimpanzees. The dominant silverback mates with all females in the group as soon as they begin ovulation. Mating and breeding occurs throughout the year. Even when she is forced too, the probability of a gorilla conceiving from the father is very low except in cross river gorilla families where inbreeding in common. The female would rather mate with the less subordinate males in the group than with her father.

Studies among mountain gorilla groups have shown that in cases where females stay with their original groups for long, they will tactfully avoid the dominant silverback/father to avoid inbreeding. Most females leave their fathers group too in order to avoid inbreeding. When they leave their father’s group, they stay alone or gang up with other bachelor males until they are able to steal females from other groups. Most males leave the group once they reach adulthood. The dominant silverback is the only one with total access to the females. The ovulation cycle occurs early (around 6 years of age) but they remain infertile till they are mature enough at 10 years. Females gorillas reach sexually maturity when about 10 to 12 years. Gorilla mating habits depend on several factors but we also need to understand their reproductive cycle. How do gorillas mate? In order to understand the evolution and behavior of our own species, we need to understand what goes on in the wild among our closest cousins, the great apes. If there are other silverbacks in the group, they will help him deal with intruders and other threats. Gorilla group members are generally peaceful allowing the silverback to focus on dealing with challenges from predators (leopards), solitary males and silverbacks from other groups. He determines what is to be done and when. The dominant silverback keeps other members in check. Among most gorilla species, interaction with other groups is very rare though it has been observed in western lowland gorillas. A gorilla group usually consists of one dominant male silverback, other males, juveniles, females and their young. Gorillas live in groups of up to 30 individuals.

Silverback meaning