h*****b
发帖数: 492 | 1 Penis bone lost through evolution
Nature 540, 486 (22 December 2016) doi:10.1038/540486b
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. | l*****n
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