- First, a chick hyena got a random mutation which led to her having a big penis (due to high testosterone). Other hyenas liked this, and it kind of became a fad.
- Additional mutations reduced the negative effects of the high testosterone levels.
- Further mutation decoupled the testosterone from the pseudo-penis. Now they don’t need to have lots of testosterone to have an impressive appendage.
Now this thing is a pretty stupid thing to have. It serves as the birth canal, and because of that, 10-20% of hyena mothers die giving birth, and 60% of all hyena cubs die. So why have it? Well, hyenas have a matriarchal society (dumb animals), and there’s one dominant female. By having a big penis, subordinate hyenas can better indicate their submissiveness and show that they’re no competition to the dominant female, allowing them to remain in the group and survive. At least that’s what the adaptationists believe.
Sounds like crap to me. I think those hyenas just like to brag.