According to recent study conducted by University College London (UCL), scientists examined the evolution of baculum, also known as penis bone. Their study findings revealed that unlike other mammals, humans do not have a penis bone and now they know why.
The study revealed that first bacula was found in mammals between 145 and 95 million years ago. Since then, the baculum size varied in animals, being large in some and smaller in others, The Washington Post reported.
Scientists discovered that the penis bone is longer in makes who engage in longer sex. When the act of penetration is longer than three minutes, known as prolonged intromission, it helped males to not only impregnate the female but also kept other male contenders at bay.
However, 1.9 million years ago, the concept of monogamy emerged amongst homo erectus and the need for prolonged sex was greatly reduced. As a result, the need for baculum became redundant, causing evolution to eliminate its need altogether, The Guardian noted.
The researchers also added that the average time between penetration and ejaculation for a regular male is less than two minutes.
The study was conducted by Kit Opie and Matilda Brindle of UCL who believed that men lost their penis bone due to evolution after monogamy surfaced as the primary reproductiove strategy.
The duo also explains that the change in mating systems would have been the final straw that led to complete disappearance of an already diminishing baculum in ancestral human men.
Another interesting theory is a religious reference that explains why men today do not have penis bone. According to Biblical professor Ziony Zevit, God made Eve using Adam's penis bone and not the rib. He argues that the word "tsela" in Hebrew means "limbs sticking out sideways from an upright human body" and not ribs that it is commonly believed to be.
