5: Gorillas don't mate for life However, through our observations, we have seen individual gorillas stay together for a majority of their reproductive years, an example being female Tuck and male Titus who were together 21 years! It just shows the level of individual variation there is among gorillas.
A few will remain loyal to the dominant silverback but will join another group in case he dies. Females have been observed changing groups several times during their lifetime. They do this to protect their future offspring.
Gorillas are not monogamous, and the males' very well developed characteristics for fighting (like large muscles and teeth) suggest that their primary strategy is to fight for new mating opportunities, not to care for infants.
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.
About 50% of males stay in their natal group, although not all eventually end up becoming dominant. Second, they can strike out as solitary males to try to create a family of their own by stealing females from other males.
And those who spend the most time babysitting end up with more babies of their own. Isabukuru, a silverback mountain gorilla that lived in Rwanda until his death last year, was known for being exceptionally affectionate toward the infants in his group.
The researchers wanted to determine whether gorillas have evolved a way of recognizing their own offspring or father. They analyzed more than 1,500 hours of data and found that there is no evidence to suggest that gorillas have a way of recognizing their own offspring or father.
Primate mother-son copulation occurs considerably more frequently than we once believed. Sade (1968) had observed but one instance of mother-son mating during his observation of free-ranging rhesus monkeys. He cited five other primatologists who had also found mother-son incest exceedingly rare.
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 Linda Vigilant of the Max Planck Institute for Anthropology in Germany.
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.
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.
Adult females are not bonded to one another and usually compete to groom and stay close to the silverback. Mothers are closely bonded to their offspring for the first three years of life.
When things are calmer, gorillas often greet each other by touching their noses together, and will sometimes even give a reassuring embrace. The females align themselves with their leader, openly soliciting mating. It is the silverback's job to keep the group safe from outsiders, but it pays to be in his good graces.
Gorillas typically live in groups of 12 to 20 individuals. That's also the range where researchers found gorillas had the most robust range of relationships. As group size grows — they can go up to around 65 gorillas — the relationships don't become more diverse, the research shows.
Do gorillas feel love? “They're incredibly tolerant,” she adds. Contrary to the common portrait of male gorillas as aggressive, chest-thumping animals, “they can be very gentle, or even loving.
Usually, only the “silverback” leader has the right to mate with the females. In case a male performs the courtship, the purpose is the same: attract a female to mate with her, for that, he gets closer to touch her and emit sounds.
For them a close relationship with their father can be vital. He protects the infants and his care increases their chances of survival if their mother dies or if she leaves the group. In such a case the silverback male is usually the only one who looks after them intensively. He even allows them to sleep in his nest.
Mating Activity
Gorillas may breed year round. Females are in estrus for 1 to 2 days per month and only the dominant silverback has breeding rights. Gorillas are polygamous in nature because the dominant silverback mates with several females in his troop.
The study shows that the parents of 9 of the 79 offspring were related as at least half-brothers and half-sisters of one another. This is consistent with recent studies showing little genetic variation among mountain gorillas, as well as signs of recent inbreeding.
“Small-bodied and vulnerable adolescent female Japanese macaques may prefer to engage in relatively safer sexual interactions with female monkey sexual partners in lieu of riskier sexual interactions with more aggressive male mates,” Gunst-Leca says, explaining that sometimes humping other animals is safer than hooking ...
Attempts both to inseminate women with monkey sperm and impregnate female chimpanzees with human sperm failed. That doesn't mean that tales of humans interbreeding with other animals haven't endured.
Gorilla fathers actually play an incredible role in raising their kids. Now they may not be as active as some animal parents, but it is up to them to protect the whole gorilla troop. They also have been known to play with their youngsters very gently and can be extremely patient with their kids' crazy antics.
Unfortunately, it is not unusual for silverback gorillas to commit infanticide when females with young infants change groups.
Male gorillas: Homosexual behaviour is observed very rarely in harem groups (occasionally during play between youngsters), but it is common in all-male groups.