Some men may feel envious when they hear this, but a whopping 80% of all mammals have bones in their penises.
This supports the penis and allows it to remain erect and copulate for long periods.
The penile bone is not connected to any other bone or joint and floats alone in the penis. Moreover, it can be moved in and out of the body during copulation to adjust the length of the penis.
Incidentally, there are more than 200 species of primates that are biologically similar to humans, but only humans do not have a penile bone.
From the perspective of other animals, the human male penis is unusual.
The reason for the lack of bone in the human penis has not been elucidated, but it may be that as intelligence increased, the need for bone diminished.
Among primates, male gorillas can weigh over 200 kg, but their penile bone is only about 1 cm, and their body size is not proportional to the size of their penis.
However, it has been suggested that this may also have something to do with the gorilla's high intelligence.
Unlike other mammals, humans walk on two legs.
Men should imagine that when they walk, they have a bony tail-keel between their left and right legs. It would be troublesome.
It is possible that the phallus bone was naturally eliminated in the process of humans evolving from leaving to walking on two legs.
Mammalian phallus bones tend to be larger in class animals in colder regions, and the Arctic walrus is nearly 70 cm long.
Class in harsh natural environments, their mating season is extremely short, so they probably need to ensure sperm delivery to females in limited mating opportunities.
Their phallus bones are so strong and sturdy that they were used as human weapons in ancient times.
One mating insertion of a walrus can last an hour or more.
In contrast to regions with long springs and summers, where they have multiple opportunities to mate, insertion time is critical in extremely cold regions where the breeding season is short.
Despite their large size, gorillas with small penile bones are not fertile and have even been listed as an endangered species in recent years.
The length of the penis and penile bone is deeply connected to the evolutionary history and biology of each animal.
