Evolution

Penis bone lost through evolution

Journal name:
Nature
Volume:
540,
Page:
486
Date published:
DOI:
doi:10.1038/540486b
Published online

Our monogamous lifestyle may explain why humans, unlike many other mammals, lack a penis bone.

The bone, called a baculum, rests at the end of the penis and is thought to provide structural support and prolong copulation. Matilda Brindle and Christopher Opie at University College London analysed the size of bacula in nearly 2,000 species of mammal, including primates and carnivores. They found that species that copulate for longer tend to have longer bacula. The same is true of animals that have more than one mate or have seasonal-breeding patterns, which lead to intense competition between sperm from different males after mating.

The results show that the baculum first evolved 145–95 million years ago, in the common ancestor of primates and carnivores. It disappeared from the human lineage after our split with chimpanzees, and this may have coincided with the switch towards a more monogamous lifestyle, the authors say.

Proc . R. Soc. B 283, 20161736 (2016)

Comments

  1. Report this comment #69151

    David Gurwitz said:

    Nice theory. So according to this, the baculum "disappeared from the human lineage after our split with chimpanzees, and this may have coincided with the switch towards a more monogamous lifestyle".

    Well I fail to see the evidence that monogamy is that old (few million years). I do not think such evidence exists or will ever be available for prehistoric times. Unless time travel becomes a reality.

Subscribe to comments

Additional data