No Bone in the Boner Means More Fidelity?

The human penis contains no bones, but the same cannot be said for many of our closest evolutionary relatives, such as chimpanzees and bonobos.

For the record, that's a macaque penis bone in the test-tube, above.

Why do some primates have a baculum (penis bone), but others do not? The baculum evolved between 145 million and 95 million years ago, which means it was present in the most recent common ancestor of all primates and carnivores. Humans seem to have lost their bacula due to shorter intromission duration, i.e. we have sex for a shorter period of time than those animals with a bacula. Longer "ties" (intromission times) often occur in species with polygamous mating practices where multiple males mate with multiple females. Apparently this is not as common in humans.

In the picture below, you can see Grover Krantz with one of his three Irish Wolfhounds. When Mr. Kranz died, he donated the skeletons of the dogs (previously deceased), as well as his own skeleton, to the Smithsonian Institution. The baculum of the giant dog can be clearly seen, below.



Related Links:
** Museum No Longer Seeks Penis Donor

** No Viagra Needed (with pictures of penis bones)
** Hung Like a Duck? (surprising things about ducks and gorillas).