"Female hyenas mate through their penises"

This is a quote from Chandler Burr’s 1996 book A Separate Creation and it’s where I first read about this evolutionary oddity in the hyena world.

Of course, a female hyena doesn’t really have a penis, it is a clitoris and a disproportionately enormous one by human standards. What this means is that the female hyena mates through her clitoris…

…which is still fucked up in the extreme, so let me explain:

Biologically, the clitoris is formed from the same tissue as the penis during the process of sexual differentiation in the uterus, as are the scrotum and labia. The female hyena can retract her clitoris (the way you might push your sleeve up your arm) to make a functional vagina, into which the lucky male can insert his actual penis.

The urogenital canal runs the length of the female’s appendage so, not only does she mate through it, she even gives birth through it. During the first birthing process hyena cubs often die because they get stuck and suffocate in the canal, which must also tear at the end to allow the cubs to pass through.

After that, deliveries get easier. And by easier I mean not actually much easier, because the cubs still have to travel from the uterus, make a 180-degree turn in the pelvis, and then successfully emerge from the clitoral sleeve - a trip which is about 60 cm long when their umbilical cords are only 15 cm long!

I think evolution fucked up a little, but haven’t we all?

Female spotted hyena Crocuta crocuta | Bernard Dupont from France / CC BY-SA