Hyenas: Nature’s Gender Benders

Medieval notions about African animals are interesting (and often amusing), in large part because most of the people writing about these strange creatures had never seen one up close, and were largely imagining their features and behavior.

One myth that persisted long after the dark ages ended, however, was the theory that hyenas are born hermaphrodites.

Sound implausible? Let’s take a look at the (confusing) evidence.

Fact 1: Male and female hyenas show no real size difference

This is stranger than you might think; in most mammal species, if you lined up the males and females side by side, there’d be a fairly clear-cut size difference, with the males significantly larger than the females. To give you an idea of just how big the gender gap is in other species: male wildebeest weigh 550 pounds on average, while females weigh in around 400 pounds; male lions average around 400 pounds, while females hover around 275 pounds; male African elephants weigh around 12,000 pounds, females weigh nearer to 8,000 pounds.

In fact, hyenas’ lack of size dimorphism is even stranger: if anything, it’s the females that tend to be larger.

Fact 2: Hyena societies are female dominant

Of course hyenas aren’t the only matriarchal species, but (like it or not) more species are male-dominant than otherwise.

Some scientists believe hyena society developed this way because of hyenas’ notorious ruthlessness, even amongst themselves. “Sharing” isn’t a concept hyenas believe in very strongly; in order to compete with males effectively for food, and get enough to produce good milk for offspring, female hyenas may have evolved to be both larger and in-charger than the males.

Fact 3: Male and female genitalia appear identical

“C’mon,” you’re thinking, “there’s a pretty quick way to separate the ladies from the gentleman. Ahem. Cough.”

Well with almost any other species you’d be right; male mammals usually have a pretty obvious calling card.

It just so happens that female hyenas are also…card-carriers.

From afar, this “pseudopenis” looks almost identical to a male hyena’s member. This may be why some scientists claimed, well into the last century, that hyena couldn’t be sexed without an autopsy (they can, it just takes pretty keen eyesight).

Don’t believe us? See how well you do: which hyenas in this video are the boys and which are the girls?

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