Apparently humans used to have penis spines...

[Mister Obvious]

[The baculum] is absent in the human penis, but present in the penises of other primates, such as the gorilla and chimpanzee.

https://en.wikipedia.org/wiki/Baculum

So apparently penis bones are pretty damn common, and it's basically only humans who don't have them.

WTF!

I mean, it's a good thing, don't get me wrong.

But it does kinda make you wonder.