Why human lost their penis bone

Scientists have discovered why humans do not have a penis bone, unlike chimpanzees, bears and most others mammals. Th penis bone, or baculum, first evolved in mammals around 145and 95 millions years ago, according to new research from university college London.
The study's lead author Matilda Brindle told the independent one of the reasons humans had lost their panis bone was because we do.not have sex for long enough to need one.The common ancestors of both primates and carnivores had a baculum she said.Humans are quite weird as we are one of the few primates that doesn't have  one .
Primates who mates for three minutes or more tend to have for longer penis bones than those whose intromission or vaginal penetration is below three minutes, she said. The human intromission duration tends to be two minutes, which most people wouldn't expect. In contrast the aye aye a nocturnal lemur , copulates for around an hat a time and has a very long baculum.
Brindle said longer penis bones were also seen in species with seasonal breeding and polygamous mating systems which humans generally do Not have. Polygamous mating systems are where multiple males and multiple females all mate with each other like,in chimpanzees, she said .
While polygamous mating does take place,among humans, it's not common enough to necessitate the retention of the penis bone.Other reasons for the lack of baculum in human is that the human mating system takes place throughout the year and is less competitive than that of other animals.
Chimpanzees, who only have sex, for around seven seconds at a time, have a very small baculum, suggesting that there might be evolutionary pressure among apes to lose the penis bone. However, the monkeys have a polygamous mating systems in which a female will mate with several males a day when she 's in heat . Male chimpanzees testicles are very large as they produce a lot of sprem to mate with several females.
( Human ) testicles are smaller, which indicates we don't have such a strong selection for males mating with multiple females St the same time.said Brindle.