Mating and breeding occurs throughout the year. The dominant silverback mates with all females in the group as soon as they begin ovulation. The moment when a female gorilla is ready to mate is not evident physically like it is in chimpanzees.
Gorillas are polygamous in nature because the dominant silverback mates with several females in his troop.
Roughly half of females reproduce in the group where they were born, resulting in the potential for them to reproduce with their fathers. However, the genetic analyses in this study found no evidence of father-daughter reproduction, although half siblings were observed to occasionally reproduce.
Gorillas live in polygamous harem groups, generally composed of one male, several adult females, and their offspring. With an equal numbers of male and female gorillas born in captivity, however, housing gorillas in social breeding units inevitably means that some males will not have access to female social partners.
A gorilla group usually has a harem structure of one adult male, or silverback, living together with several adult females (three to six) and their offspring. The task of the silverback is to lead and protect the group.
In the wild, gorillas can live to over 40 years old
Males between 8-12 years are called 'blackbacks'. Then from 12 years old, they develop a silver section of hair over their back and hips, earning them the name 'silverback'.
Although gorilla groups are led by a dominant silverback (adult male), who determines the group's daily travels and certain other activities, adult females play crucial roles in the success of every group.
To curb inbreeding, though, they appear to tactically avoid mating with their fathers. This strategy works so well that the chances of alpha gorilla males siring the offspring of their own daughters are effectively zero, according to new research.
Gorilla moms have a roughly 8.5-month long gestation period, and infants weight about 1.4 – 1.8 kg (4 lb) when they're born. That's half the weight of the average human infant! However, gorillas grow faster and reach maturity around 12 years old.
Males of both the Virunga and the Bwindi populations frequently direct aggression to females, sometimes in the form of herding (in the presence of an extragroup male), but more typically as spontaneous displays or threats, involving stereotypic strutting, chest beating, and vegetation thumping.
Gorillas
Gorillas are animals that have sex for pleasure, and females will engage in lesbian sex when males reject them. In fact, many species of primates are notorious for their homosexual behavior. Scientists have observed female gorillas climbing on top of each other and pushing their bellies and genitals together.
Gorillas have been caught on camera for the first time performing face-to-face intercourse. Humans and bonobos were the only primates thought to mate in this manner. And while researchers have observed wild gorillas engaged in such an act, it had never been photographed.
Males love their infants, too. It's all about family! This is possibly the best way to describe the role of a gorilla male as a father.
Polyandry also occurs in some primates such as marmosets, mammal groups, the marsupial genus' Antechinus and bandicoots, around 1% of all bird species, such as jacanas and dunnocks, insects such as honeybees, and fish such as pipefish.
In the animal kingdom, when it comes to mating, promiscuity is the rule rather than the exception. About 90 percent of mammals have multiple mates, and cheating on social mates is observed in almost all species. In fact, only 3 to 10 percent of mammals are even socially monogamous.
Bonobos and humans are the only primates to typically engage in face-to-face genital sex, although a pair of western gorillas has also been photographed in this position.
Gorilla mothers have very strong bonds with their infants, and provide complete care for them during their first few years, starting with carrying them everywhere against their chest, and then later having them ride on their backs.
Elephants have the longest pregnancy period of any living mammal. If you – or someone you know – has experienced a pregnancy that seemed to go on forever, spare a thought for the elephant. It's the animal with one of the longest gestation periods of all living mammals: nearly two years.
Females reach sexual maturity at 7 – 8 years of age, but normally will not breed until several years later. Males reach sexual maturity about 11 – 13 years, but normally do not father offspring until they reach silverback status and have a family group of their own (about 15 – 20 yrs of age).
Although it's hard to say anything with absolute certainty, human DNA is so different to even our closest relatives that interbreeding is probably impossible. Despite this, Gallup believes that it is possible to crossbreed humans with great apes, including gorillas and orangutans.
5: Gorillas don't mate for life
While adult male and female gorillas may spend long periods of time together, gorillas don't mate for life. Females can be seen transferring groups many times throughout their lives, giving them the opportunity to live with and produce offspring with many males.
The female would rather mate with the less subordinate males in the group than with her father. 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.
While the average group size is around 10-12 individuals, groups have been seen to have as few as a single breeding pair, or two silverback gorillas, to as many as 65 individuals!
Generally, gorillas are very shy and reserved towards people. They will attack only if they are surprised or threatened or if a person behaves in the wrong way. If the human makes an unexpected movement, the silverback male can react with horrific roaring and bluff charges.
Each has a lowland and upland subspecies. Gorillas live in family groups of usually five to 10, but sometimes two to more than 50, led by a dominant adult male—or silverback—who holds his position for years. The bond between the silverback and his females forms the basis of gorilla social life.