From the News: Japanese zoo fails to breed two hyenas after both turned out to be male

Japanese zoo fails to breed two hyenas after both turned out to be male

Okay, okay, it's easy to laugh, but this one is legit.

The genitalia of male and female spotted hyenas look very similar, so similar that the ancient Greeks thought hyenas were all hermaphrodites.  I've even read one case study of an animal dealer who was commissioned to capture four hyenas - two male, two female - for a zoo.  He caught two males quickly enough, but no matter how hard he searched, he couldn't find a single female.  Then, one of his captive "males" gave birth.

Many zoo breeding programs run into the problem of matching a male and female.  Some animals are sexually dimorphic, meaning that the males and females look different.  Lions have manes and lionesses don't; male deer have antlers (for part of the year, anyway) and females don't (except caribou).  In some birds, especially many pheasants, the male is brightly colored and the female isn't.  In other cases, sexing animals can be tricky.  Today we have DNA, x-rays, and all sorts of high tech techniques.  In the old days, you put two animals in an exhibit together and hoped.

Well Maruyama zoo, better luck with that female...