Humans don’t have penis bones because sex doesn’t last long enough

The human penis does not have a bone. Something which the majority of us will have long since worked out.

That's not to say, however, that all the penises on this wonderful planet are completely bone-free. Mammals such as chimpanzees and bears both have a penis bone, or a baculum, to give it its sciency name. Now, research from University College London reckon they've worked out the reason us humans are baculum-less. According to them, the bone first evolved in mammals around 145 and 95 million years ago, with the study's lead author Matilda Brindle telling The Independent that one of the main reasons us humans (men, to be more accurate) lost our penis bones was because our sex doesn't last long enough for us to need one. “The common ancestors of both primates and carnivores had a baculum,” she explained. “Humans are quite weird as we’re one of the few primates that doesn’t have one.” According to her, primates that have sex for more than three minutes at a time tend to have a far longer penis bone than those that don't tend to last quite as long. Slightly embarrassingly, this means us. “The human intromission duration tends to be below two minutes, which most people wouldn’t expect.” Brindle also explains that longer penis bones were seen in species with polygamous mating systems or seasonal breeding. “Polygamous mating systems are where multiple males and multiple females all mate with each other, like in chimpanzees,” she added. “While polygamous mating does take place among humans, it’s not common enough to necessitate the retention of the penis bone.” So now you know.