Female hyenas have last laugh
Not until the 1930s could modern science easily tell the difference between girl and boy hyenas. Dr Karl has been getting up close and personal with one of nature's original gender benders.
Over the last few episodes, I debunked the three big myths about the spotted hyenas.
These myths are: that they are some kind of dog, when they're actually a kind of cat; that they have the most powerful bite for their weight, which they don't; and that they are loathsome cowardly scavengers, when they catch and kill 95 per cent of what they eat.
But Hyena World gets even weirder. Not only does the female spotted hyena outrank the male, but she also has an organ that looks exactly like the male's penis.
Even stranger, this is what she gets pregnant through, and even gives birth through.
Hyenas are not solitary scavengers. Instead, these sophisticated hunters live in complex clans of up to 80 members.
They live in communal dens, a collection of underground tunnels with many above-ground entrances.
They come together only for three occasions: kills, defending the territory, and to hang out at the communal den.
Their territory ranges from 40 to 1000 square kilometres.
There are very few female-dominated societies, but spotted hyenas have such a society. The lowest status female outranks the highest status male. The females are more aggressive than the males.
The high-ranking female cubs are off to a golden start in life. A high-ranking hyena gets first access to the food, as well as more powerful allies and a better grade of protection.
As a result, she has a longer reproductive life, and more litters. Her teeth are in better condition, because she gets first pick of the kill, and so she doesn't have to crush bones that can damage her teeth. Instead, she feasts on the best and most tender meat, unlike the lowly males.
Alpha females are younger when they first get pregnant, they get most of the matings, they have cubs more often and they have a greater survival rate for their cubs.
Even so, all the females have cubs, because they can pick and choose from the low-ranking males.
About 90 per cent of males leave the clan when they become sexually mature, around the age of two or three.
They then have to spend two years as a junior male, with no matings during that time. They are the very lowest ranking animal in the clan, being bossed around by all the other males and females, and having the very last access to the food and females.
It's a very hard life being a male spotted hyena.
Now it's been known for a long time that there was something special about the sexual anatomy and physiology of the spotted hyenas.
Quite a few of the ancient writers declared that the spotted hyena was a hermaphrodite with the genitals of both sexes in one body, or that it could change its sex.
But it was only as recently as the 1930s that modern science examined hyenas.
The females have a clitoris that looks just like a penis, and through which they give birth!
The clitoris is so enlarged that it looks just like the male hyena's penis (the zoologists call it a 'pseudopenis').
The female spotted hyenas do have a vagina, but it does not open directly to the outside world. Instead, it communicates with the outside world via the pseudopenis.
It is a true vagina, both in its appearance to the naked eye, and under a microscope. But like the male hyena's penis, the female pseudopenis has two 'corpora cavernosa' and a single 'corpus spongiosum'.
This means the female spotted hyena could have a genuine erection of its pseudopenis, just as the male could with his penis. It is even as long as the male's penis (about 17 centimetres).
The female's labia are fused together, and because it has two fatty pads, looks almost identical to a male's scrotum.
Sometimes even hyena specialists cannot tell the difference between boy and girl hyenas, until what they thought was a boy gives birth.
The female spotted hyenas urinate, copulate and give birth through the pseudopenis.
Mating is impossible without the full cooperation of the female. The male has to balance very precariously, because of the orientation of the pseudopenis.
Spotted hyenas are not solitary, skulking, cringing, cowardly scavengers. Instead, they are sophisticated and skilled hunters that live in a complex female-dominated society.
The doting mothers are very caring, tolerant and affectionate, and probably invest more time and energy in their young than any other animal.
Unfortunately, spotted hyenas have such an undeservedly bad reputation that zoos don't want to carry them, and conservation groups don't want to adopt them (After all, have you seen a hyena on a conservation T-shirt recently?).
So we don't get to see them at close quarters, and we don't learn the real facts about these amazing gender-bending, role-reversing animals.
Published 15 December 2009
© 2014 Karl S. Kruszelnicki Pty Ltd