Why humans lost their "dingbats" during evolution？

At the end of the penis in most male mammals is a unique bone - the penis bone, also known as the dingus, which is a bone that is independent of the skeleton and not attached to other bones in the body, but hangs subtly at the end of the penis.

This bone has many advantages in animal mating and can improve the ability to reproduce offspring. Such a "secret weapon" is common in most mammals. Among all primates, humans and spider monkeys are the only ones without penis bones, while other primates, carnivores, insectivores, rodents, bats, etc. have many species with penis bones. The closest relatives to humans, bonobos, have retained their penis bones. Is the loss of the penis bone during human evolution a degeneration or an evolution?

What is a penis bone?

The penis bone, which is prevalent in most mammals, is largely rod-shaped and is normally hidden in the animal's abdomen, and only when needed is it pushed through a group of muscles into the fleshy tissue of the penis to keep the dingus constantly stiff during mating.

It is important to know that most mammals mate very frequently and for a long time. The advantage of having a penis bone is that it allows them to mate for much longer and more often when they are communicating genetically, which means they can mate with more females and thus pass their genes on more widely.

The dingbats are also the most bizarre of all bones, and this bone varies tremendously from species to species in shape, length size, and texture. For example, the dingbats of the primate ring-tailed lemurs and bonobos are only a few centimetres and millimetres respectively, while the dingbats of the majestic walrus are 60 centimetres long, accounting for 18 percent of their body length. The shape also varies, with some resembling forks, some spoons, some strainers with spikes, some naked like a thin stick, some with serrated edges; and some with hooked spines at the end.

The fact that the dingbats have such diverse morphology suggests that animal dingbats have evolved rapidly. So, what benefits can be derived from the evolution of the ringtone? Why do most mammals need to grow a penis bone in their dingbats?

Possible reproductive advantages of the penis bone

During mammalian mating, if the male's penis is not firm enough to function adequately, he may not be able to complete the sexual intercourse process, making it impossible for the female to successfully conceive, thus preventing the male's genes from being passed on. Therefore the evolution of the ding-dong is crucial. So what are the benefits of having a ding-dong bone for animals?

1. Extended mating time.

The most direct benefit of having a firm ding-dong bone is that it allows males to last longer during mating, which can greatly extend the mating time and help improve the chances of female conception. Extending the mating time prevents the female from escaping before her "tadpoles" come into play, reducing the frequency of females going to mate with other males and thus increasing the chances of passing on their genetic material.

2. Trigger ovulation in females

For some species, such as female cats and lionesses, if they do not mate, they will not ovulate, but only when they mate with males. Such females are in need one emulation from the ding bone to expel egg cells. The reason why the dingbats of some species have evolved into spike-like or hooked surfaces is to increase the contact surface and add extra stimulation to more effectively promote the release of egg cells by the female, thus increasing the success rate of reproduction.

3. Reduce friction

Scientists have also proposed the "vaginal friction hypothesis", which suggests that the presence of the ding-dong bone allows males to overcome friction to the greatest extent possible during mating, making it easier and smoother for their penises to penetrate deeper into the female's body.

4. Reproductive protection

Some males have hook-shaped dingbats, which are used to clean out the sperm of the previous male from the female's body during mating, increasing their chances of reproduction.

In addition, the different shapes of the dingbats each have their specialize: some have the role of pleasing the female; some can send the sperm deeper to prevent slipping out; some prevent the female from breaking free, that their tadpoles to increase the success rate of conception; some can hurt the female's private parts so that each other can not mate with other male rivals.

All in all, male penis bones exist for the purpose of improving reproductive success and increasing the chances of passing on their own genetic material.

Possible reasons for the degeneration of the human dingle bone

Scientific studies have found that the ringtone emerged between 145 and 95 million years ago, after the divergence of placental and non-placental mammals and before the emergence of the common ancestor of primates and carnivores. This implies that the common ancestor of primates and carnivores had dingbats. At present, the majority of primates retain their dentifrices, but humans do not. This shows that humans had a "ding-dong bone" earlier, but only in the process of later evolution gradually disappeared.

The ding-dong bone has so many benefits, so why did humans still lose it?

We know that almost all wild mammals in nature have an estrus period, and only in the estrus period for mating and reproduction, there are often only a few days in a year to focus on energy to do a major event, time is tight, plus the wild environment is always facing danger, and competition between the same kind, so it is very much in need of dingbats to improve the efficiency of mating and reproductive success rate! And as a higher animal humans, there is no such pressure!

Humans have no time limit, and less competition to choose a mate

Humans do not have a seasonal estrus period and can mate at any time throughout the year. And humans tend to be monogamous marriages, male and female relationships are strong and long-lasting, competition between males is not great, do not have to worry about their DNA being replaced by rivals, and there is no need to rush to impregnate females before competitors come like other mammals. One interesting study found that for mammals with intense reproductive competition, the more intense the competition for mate selection faced by males of a species, the longer their dingbats would be.

A related study was conducted by a scientist who divided rats into two groups: those with multiple mates (multiple males and females) and those that were monogamous. After 27 generations of breeding, it was observed that the offspring of the polygamous female rats had larger dingbats, while in the monogamous group the dingbats became smaller.

Mating time

Generally speaking, animals with dingbats take longer to mate, but human ancestors were not among the "long mating" species, and were "fast shooters" in the animal kingdom, with an average time of about 2 minutes to finish the fight, much less than many mammals with dingbats. The average time to end a fight is about 2 minutes, far less than many mammals with dingbats. Therefore, the support of the ringtone is not necessary for humans...

Genetic alterations

By comparing human DNA with that of other animals, researchers have found that humans are missing more than 510 DNA fragments over time, including the genes that control the growth of a single bone. Some researchers have interfered with gene expression in the ding bone of mice, causing them to lose their ding bone, only to find that the mice had significantly increased brain volume.

Human males with penises that do not have a ringtone and rely entirely on transient vascular engorgement of the cavernous body during copulation also do well.

Conclusion

The above factors, the human male enduring artifacts in the evolutionary process of species gradually degraded, but saved a lot of time to work and develop the brain, over time, so that the brain capacity has a qualitative improvement, thus ascending to the top of the food chain, to promote the development of human civilization. So instead of saying that the disappearance of human dingbats is a kind of degeneration, it is another kind of evolution!