The “baculum”, or penile bone, is one of the most mysterious structures in mammalian biology. To date, no one really knows what it is doing and why it is missing in humans, horses, elephants and some other species.
3D analysis of 82 penile bones of various animals shows that some of the strangest shaped penile bones prolong sex very long, induce ovulation in women, and sperm from other romantic encounters. I found that I could scrape it with a shovel.
For example, the male honey badger penile bone is one of the most bizarre appearances. It’s almost like an ice cream scoop, and this development could have evolved to fend off competition and ensure that the male offspring really belong to him.
In this study, complex shapes were not related to animal testis size, but there was a weak correlation between longer mating attacks and induced ovulation, and these bones reduced sexual competition. It suggests that it will be useful.
Previous studies have shown that the width of the penile bone is somehow associated with more offspring of the mouse, but it is not yet known why. The theory that these men’s penile bones somehow prolong sexual intercourse and defeat competition has been raised earlier, but the results are mixed.
Probably because you overlooked one of the most important features.
“The reason naturalists are so fascinated by Vacula is that they have many unusual features, such as strange ridges and grooves, strange curvatures and strangely shaped tips,” said Biologist, the lead author of Manchester Metropolitan University. A survey by scholar Charlotte Brassie mentioned earlier in 2018 about the team.
“Our research is particularly novel in that it employs a 3D approach to understanding the evolution of the baculum. However, all previous attempts to study the baculum are very basic in bone length and width. Simplified to a basal measurement and ignored all this important thing. Shape information. “
Penile bones vary dramatically in size and shape from species to species, but current analysis by Brassie and Team shows that the most “complex” penile bones, including elaborate tips, hooks, scoops, and urethral grooves, are carnivorous. Animals and, strangely, a single species.
Unlike other dull and suddenly ending penile bones, animals with more elaborate tips are thought to have evolved under stronger sexual competition.
“But contrary to our expectations, the’socially monogamous’species have been found to have high values for optimal penile complexity,” the author writes. I am.
At first, this doesn’t make sense. Monogamous partners are less likely to face sexual competition after mating than species that mate with multiple males.
Still, the author explains that social monogamy is not equivalent to genetic monogamy. For example, wild African dogs are classified as monogamous, but there is evidence that co-breeding is happening wisely anyway.
Although group-living carnivores appear to evolve towards a more simplified rod-shaped baculum, the authors found that the bones of the socially monotonous species of penis have a very complex shape. I discovered that it is evolving toward.
Polygamy seals and sea lions, on the other hand, are far less likely to face sexual competition because they live in harems where one male mates with multiple females. Interestingly, the pinniped baculum ends with a relatively simple tip, while the wolf and dog baculum bones show evidence of deep urethral sulcus and bulbar granule attachment.
Current X-ray-based studies of modern museum samples are one of the most rigorous analyzes of carnivorous penile bones. Unfortunately, however, the three-dimensional nature of female genitals has historically been overlooked and poorly understood.
Therefore, it is unclear how the penile bone actually works during sexual intercourse. In the future, we would like to analyze these structures from within the female reproductive tract.
Such studies may give too much emphasis to the bone itself, but give a better understanding of the function of the penile bone during sex. After all, analyzing a single ossified element reveals little about the complexity of the glands and the cartilage above them.
“This element does not currently exist in most museum specimens, so it does not exist in our analysis,” the author admits.
“Similarly, our analysis implicitly assumes that penile bone complexity is an accurate substitute for penile shape complexity.”
Future studies will also need to incorporate the soft tissue of the penis. That way, you can better understand how the baculum evolved among the different species, and why some species like us lack it.
“As mammals, and more specifically as apes, it’s unusual for humans to have no penile bones,” says Brassie.
“By studying the role of the baculum during mating, we would like to further clarify why some mammals, including humans and hyenas, succeed in breeding without the baculum.”
The study was published in Bulletin of the Royal Society B..
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