by A study confirms that primates have been masturbating for at least 40 million years and that they do so regardless of gender and age. But what is the evolutionary advantage of masturbation? This is the question the researchers tried to answer.
Masturbation can increase a male primate’s chances of having children. According to a new study from University College London (UCL), personal pleasure can contribute to successful fertilization because it increases arousal before sex. Scientists have also concluded that ejaculation after masturbation helps eliminate poor quality sperm, leaving better sperm available for mating.
Additionally, the researchers add that masturbation may also reduce the risk of contracting sexually transmitted infections (STDs).
“Our findings help shed light on very common but poorly understood sexual behavior and represent a significant advance in our understanding of the functions of masturbation,” said lead researcher Matilda Brindle.
So excited to share our new article on primate evolution #masturbation! 🐒🦧🦍 Masturbation is an ancient trait in primates and linked to reproductive success + reduction of STIs in males! 👋🍆💦 Less clear for women – we need more data! 👉🌮🌊https://t.co/d2x3AVNUSB
— Matilda Brindle (@Matilda_Brindle) June 7, 2023
In the study published in the journal Proceedings of The Royal Society B, biologists trace the origins of masturbation to ancient primates that predate early humans by tens of millions of years. Masturbation is common in animals, but is thought to be more common in primates, including chimpanzees, monkeys, and humans.
Due to a lack of data, Brindle cannot say for sure whether early primates masturbated. “What we can say is that this behavior was present around 40 million years ago in the common ancestor of all apes and great apes,” explained Matilda Brindle. “It’s not like some species woke up one day and started doing that. It is an ancient trait and part of evolution.
The study focused on primates, both wild and captive. The Brindle-led team gathered information from 246 published academic papers and 150 questionnaires, with the aim of understanding when and why masturbation evolved. To fill in the data gaps, the scientists sent questionnaires to primate experts and zookeepers to get details about their observations of primate masturbation that hadn’t been recorded by previous studies. This was especially important for news about female masturbation, Brindle said, which tends to go unnoticed due to the lack of easy-to-detect erections.
Researchers have gone as far down the history of behavior as possible in hopes of understanding the origins of what, at first glance, appears to be an evolutionary puzzle. From an evolutionary perspective, masturbation seems pointless, disruptive, pointless, and even risky. So, having identified when, the researchers turned to why.
The team describes how masturbation appears to be common among primates of all sexes and ages. At first glance, however, the benefits of this behavior are unclear. Why does this happen then? It seems like an evolutionary paradox: why would an animal waste time, energy and reproductive resources pleasing itself rather than copulating with a mate?
Historically, biological studies have overlooked females, giving the authors little data to go on. Scientists say the benefits of female masturbation – from an evolutionary perspective – therefore remain less clear. For men, however, there are at least some tips.
Non-functional hypotheses posit that masturbation is a pathology or by-product of strong underlying sexual arousal, while functional hypotheses support an adaptive advantage. These researchers found data that support the hypotheses of postcopulatory selection (which states that masturbation increases the chances of fertilization) and pathogen prevention (which states that masturbation helps reduce infections by releasing pathogens from the genital tract ) in male primates, suggesting that masturbation may be an adaptive trait, operating on a macroevolutionary scale.
How does masturbation help increase the chances of getting pregnant?
For example, a weaker man might masturbate just enough to increase his arousal before intercourse, meaning he’ll inseminate his partner faster – and before a beefy competitor has a chance to interrupt copulation.
In addition, masturbation can also help men eliminate old sperm, leaving them with fresh and therefore better quality and more competitive sperm for sex with their partner.
The researchers also found that male masturbation in primates increased countercyclically with levels of sexually transmitted infections. One explanation could be that masturbation after sex helps cleanse the birth canal, reducing the risk of infection.
What about female masturbation?
For women, previous studies have shown that arousal increases vaginal pH, creating a more hospitable environment for sperm, while vaginal mucus filters out low-quality sperm and rapidly transports high-quality sperm to the uterus. . Orgasmic contractions can also help sperm on their journey.
But the disease-related hypothesis is not confirmed. “Normally the vagina is slightly acidic to keep pathogens out,” Brindle told Science News, but it becomes less acidic when the female primate is aroused, so sperm aren’t killed off. entrance. Making the vaginal environment safer for sperm also makes it safer against pathogens. However, due to a lack of data, the study was unable to advance in this line of investigation.
Either way, the stigma surrounding the study of masturbation and sexual behavior is diminishing, Brindle noted, giving him hope that more discoveries will be made soon. “It’s such a common behavior in the animal kingdom that I find it absolutely baffling that no one has studied it before,” Brindle said. “For people who think masturbation is bad or unnatural in some way, [é preciso dizer que] this is perfectly natural behavior. It’s part of our healthy repertoire of sexual behaviors.
This is an area of research that is still little explored, the scientists point out. There are other mammals, as well as birds and reptiles, that also masturbate. Therefore, “if we want to understand the larger evolutionary picture of this behavior, we need to look beyond primates.”
