A new study suggests that monogamy and how long humans have sex may be the reason why men don’t have bones in their penises, while other male mammals like bears, chimps and gorillas do.
The study, conducted by a pair of researchers from the University College London, found that prolonged intromission — penetration lasting longer than 3 minutes — was correlated to the presence of a penis bone, or baculum, which vary dramatically in length, width and shape among male mammals that have them.
The research, which discovered that the penis bone first evolved in mammals between 145 million and 95 million years ago, found “prolonged intromission” predicted a longer baculum in primates and carnivores. The findings were published Wednesday in the Proceedings of the Royal Society, which noted the baculum’s description as the “most diverse of all bones” due to extreme variances across mammals.
