Why do chimpanzees have large testicles?

Easy reviews of the sexuality of the APES (orang-utang, gorilla, chimpanzee and Homo sapiens)

And what do you think the size of the gorilla's penis? big... huh? Well, contrary to all the myths, the giant gorilla has a penis measuring 3 cm (length, not thickness) and that too - only it is erect (not the gorilla); Besides, his testicles are also small. We, on the other hand, have testicles larger than the gorilla, but smaller than those of the chimpanzee (which are really huge relative to the body). Our penis, compared to our ape relatives, is large; I wonder why. One can also ask why human girls always have prominent breasts (and not only during pregnancy and breastfeeding - as with the cashiers) and always prominent posteriors (and not only during estrus)... and in general why man is always ready for intercourse and the woman's estrus is hidden unlike most animals, including the gorilla and the common chimpanzee.

These questions are more interesting than why a giraffe has such a long neck, or where does a peacock get its magnificent tail, because they are related to us and related to sex - which is always interesting. There should be explanations for the differences we mentioned between humans and those apes that are 99 percent genetically similar to us. We are closer to chimpanzees than a horse is to a donkey (therefore it is interesting to think what would have resulted from a mating between a human and a chimpanzee).

The female chimpanzee has a prominent signal that she is in heat. She has huge bright red bumps on her back. The males see this, stand in line and each one does his part in an average time of ten seconds. By the way, the dwarf chimpanzees, called bonobos, have sex at every opportunity and not only during heat, and thus they are more similar to us than the common chimpanzee.

The permissive behavior of chimpanzees is the reason for their very large testicles (almost three times ours, even though their body weight is half ours). Those males who excelled in large testicles and therefore a large amount of sperm, managed to pass this trait on to their offspring (the one who injected the most, had a great chance of getting pregnant). In general - individuals who excel in traits that make them attractive to the opposite sex, or in other traits that bring them more offspring, or in traits that ensure their survival at least until after the reproductive stage, will pass these traits on to those who come after them and the genes responsible for these traits will spread in the population. This is the whole theory of evolution on one foot.

The size matters?.. but how is it determined?

Now we will explain why the gorilla does not have large testicles and why his penis is so tiny. In gorilla society there is one dominant male. He is big and he is a bully and all his females and no one dares to compete with him. Therefore, the characteristic that developed in the gorilla is the size and strength of the body and it does not need large testicles. He has no competitors in fertilizing the females, so there is no need for a large amount of sperm. Besides, how often does the gorilla do this - maybe once a year - even if he has a harem of several females, a pregnant female does not work; Likewise, about four years after the birth and after that - only two days a month until the next pregnancy. As for the size of the penis, the penis is also used as an organ of presentation - probably not so much towards the females (it seems that the size does not have a decisive effect on the orgasm in the female), but towards other males (the males are always busy with comparisons and the females are less interesting). With our ancestors - the early human races, the owner of the large penis was able to buy himself a status that guaranteed him more descendants. You can see today in chimpanzees that when there is a conflict between two groups, the dominant males stand in an aggressive position and because of neural connections in the brain, aggression is linked to food and sex. The menacing chimpanzees can be seen making chewing movements and having an erection. Whoever has a bigger one is more threatening and this gives him an advantage - he overcomes and even kills the opponent. Similar phenomena existed in the ancient human races and these are the reasons why we have more apes. The bully gorilla has no problem competing with other males and dealing with other packs, so he doesn't need a large organ and settles for something really microscopic.

How long does it take them?

Before answering this question, we will describe the socio-sexual structure of the various great apes. The adult orangutans live in solitude - each to himself. The male with the territory announces it by roaring and thus he calls the female. They meet for mating and then everyone goes their separate ways. The gorillas live in a group of a dominant male with several females and young. Only the dominant male copulates with the females (although others sometimes try, when he is not watching). As mentioned, the chimpanzees live in groups of many males and many females and everyone does it with all of them. There is another species of apes - a little further away from us and that we have not told about their sexual behavior. These are the gibbons and they just live in permanent pairs - really not interesting.

We mentioned that chimpanzees finish things in ten seconds. The gorillas are also close to us but a little less than the chimpanzees - it takes them a minute to a minute and a half. The orangutang, on the other hand, spends ten minutes or even fifteen minutes on the business. It is interesting to see that those who are closer to us, finish faster, but the reason for this depends on the sexual social structure that we have described. The chimps have to finish quickly to allow their friends too. The gorilla, he usually has no competitors but sometimes another adult male in the group will be able to do so as well. Orangutans, on the other hand, live in solitude and when a couple meets - they have all the time in the world - no competitor is around.

Virginity and rape

The great apes generally prefer females that have already proven themselves in childbirth. Let's see what happens with the orangutang; Well, with them, a virgin female is interested in a mature, strong, experienced and territorial male. For his part, he shows no interest in her at all. There is a catch here, because until she gives birth at least once, he won't look at her. And here is a mature male, but one that doesn't have a territory yet, encounters a virgin virgin and wants to mate with her. She does not submit to him and really resists. The young man raped her, literally, but the rapist got hired; First, at least she was violated by an agile and enterprising male who was strong enough to rape her (a genetic advantage for her offspring) and secondly - she got out of the trap; In the next heat she will be able to get an older, strong and territorial male.

Why men rape and women cheat

We are currently moving to the great ape of the species Homo sapiens sapiens. In ancient times and even today in times of war - rape is a common phenomenon. Man Shans - he had many offspring. So, as much as it doesn't sound nice - the tendency to rape is in our genes. Another factor in the equation is that rape, like other forms of violence, is restrained by social norms and rules of morality.
The same logic that applies to rape also applies to betrayal, which is more normative.
Indeed, from many studies conducted in Western society, extremely high rates of infidelity were found - higher in men, but quite high in women as well. While conducting various genetic surveys, the researchers noticed the phenomenon that many of the children are not the sons of their declared father. The extent of the phenomenon varies in different periods and in different countries and may even reach tens of percent.
The evolutionary benefit that males derive from cheating is clear - they have more offspring; But what benefit do the women derive from this?
Several answers or options were given for this.
* The traitor tied to herself an additional breadwinner who helped feed her offspring.
* In case of the death or disappearance of the spouse - the woman had an exchange spouse.
* The permanent partner had better skills as a breadwinner, but this one of the Stutz had better genes in many other areas.
From this it is easy to understand that the traitors had more offspring and their chances of survival were better.

Breast size and hidden ovulation

Why do women (unlike the human breasts) have relatively large breasts, even before the first pregnancy. A fairly old explanation claims that a woman's breasts, which are always prominent (and not only during pregnancy and breastfeeding), evolved to attract the male, from the time our ancestors straightened up and the position became frontal - instead of the bulging and shiny backs of the breasts during heat. Another explanation claims that the woman's breasts, which contain fatty tissue (regardless of the quantity and quality of the mammary glands), together with fat buttocks, signal to the male that the female is in a good nutritional state, which ensures energy reserves to nourish the fetus - in short, better chances of success for pregnancy and the birth of a healthy baby.
Another explanation for the woman's breasts and her back which are always developed, is related to the issue of estrus or hidden ovulation. In humans, unlike most apes - there are no signals about the time of ovulation and humans are always ready to mate. The question arises as to why our ancestors developed secret ovulation and, in fact, also intimate mating - not in the presence of an audience - unlike all other animals, including great apes that mate in public. And the explanation is not as in a joke - to prevent gatherings for the purpose of giving advice to the couple. Actually there are several explanations to speak of and they excel at different levels of male chauvinism or feminism (perhaps depending on the gender of the people who proposed them).
A. Preventing quarrels - strengthening cooperation between the male hunters.
B. Strengthening the marital relationship. The woman always rewards the man and he stays to support and help raise the offspring.
third. The woman takes advantage of her constant readiness for sex - to receive food from different males or to tempt males from the top of the hierarchy.
d. If ovulation was visible, the male would go the rest of the time to other females. When hidden, the male remains to ensure that the female is fertilized - and only from his seed.
God. Many animals, including monkeys, kill cubs that are not theirs, and violate the mother to create their offspring. If the ovulation is hidden, the males don't know if the offspring is theirs and then they don't kill it and help provide food.
and. The human fetus is large, relative to the size of the mother, several times that of the monkeys. This caused birth problems and maternal mortality. The human female could avoid contact during ovulation, but when ovulation is latent, she cannot.
It can be simply said that the evolutionary process of the human female was in the direction of constant estrus (in terms of willingness to have sex) and constant advertisement for estrus (breasts and rear), to strengthen the marital bond and create the institution of the family.

orgasms

Sometimes they like to give evolutionary explanations instead of simpler and more logical explanations. For example, in a study in England it was found that a woman who cheats on her permanent partner, her uterus receives many times more sperm than with the permanent partner. The explanation - the woman wishes (subconsciously) to conceive from the outstanding lover (in her opinion) with better qualities than those of her permanent partner. But there can be another simple explanation for this - with the lover the orgasm is stronger.
The same researchers also found that a man who maintains relations with his partner, so if most of the time they were not together since the previous contact - he will emit three times more sperm cells than if they were together most of the time between the two contacts. The explanation - the man emits more, to compete with the semen of others who may have done it with his partner when he was not seeing her. A simpler explanation - after the breakup the orgasm is stronger.

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