Our ancestors had a bone in their penis, here is why it disappeared

The body of modern humans is the result of millions of years worth of evolution. During the process, we gained and lost many organs and body parts as our bodies adjusted to the time and conditions. One such organ was the penis. The male reproductive organ comes in all shapes and colours and this is not by chance. It has evolved to perform its function in the most efficient way. The male reproductive organ of our primate ancestors had a special feature that may surprise you.

The baculum: a floating bone in the penis

This special feature is the baculum. Still present in many mammals, this penile bone can measure from a few millimetres to several centimetres, and is completely detached from the skeleton. Its function intrigues scientists, although they put forward several theories:

• It acts as a protection for the penis, making it less fragile during a long intercourse
• It makes the sperm travel further during ejaculation
• It would stimulate the reproductive system and promote ovulation
• It would facilitate sexual intromission (vaginal penetration)

All of this would contribute to increasing the male's chances of reproduction. In other words, to ensure that he has offspring! Many animals have this curiosity, such as cats, chimpanzees, bonobos and walruses. And it turns out that our primate ancestors also had a baculum, except that evolution decided to separate us from it.

Little sexual competition

So why did we lose this bone? Our sexual habits and our 'poor performance' could be the reason. In primates, a correlation has been observed between the presence of a baculum and a long duration of intromission (penetration of the penis until ejaculation). However, in men, the average duration of sexual intercourse, excluding foreplay, is less than two minutes. This means, unlike minutes-long porn videos, our intercourse is generally very brief. So brief, that a floating bone in our penis would offer us no useful protection.

Moreover, in nature, sexual competition can be extreme. Many species are polygamous and their specimens must ensure that their own sperm reaches the eggs before those of others. Since Homo sapiens are generally monogamous, the baculum would be less useful to us for this reason too. According to National Geographic:

Among primates, monogamous species tend to have much smaller bacula than species where males compete for mating. So it wouldn’t be crazy to assume that the shift towards monogamy in our ancestors made the human baculum disappear altogether.

This article was translated from Gentside FR.

Sources used:

-National Geographic: A Most Interesting Bone

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