Scientists explain the Koala's deep and somewhat nauseating mating grunt

When a male human is trying to win back the affection of a female human, he can find inspiration in a famous scene from the 1989 movie "Say Anything...". A scene in which a lovesick teenager stands outside his beloved's house in a trenchcoat and holds up a boombox playing Peter Gabriel's 'In your eyes'.

Now, Hollywood doesn't make movies for koalas. Koalas have lousy vision, and they have little or no money. But if they did remake "Say Anything..." for a koala audience, a lovesick teenaged koala would stand outside his beloved's house, and hold up a boombox playing this:


That's a male koala's mating call. To a female koala, apparently that's haunting and stirring, instead of scary and kind of nauseating. And to scientists, it's also mysterious: how, they wondered, does such a small animal make such a low-frequency sound?

Anatomically speaking, a male koala's larynx should not be able to produce such deep grunts. And now, biologists have discovered that it doesn't -- at least, not on its own. Those super-sexy, come-hither squawks are made with the help of fleshy folds in the koala's pharynx, which extend from its soft palate to its throat. These folds stretch when the male koala inhales, enabling it to really hit the low notes. Which it's important for them to do, because it makes their calls louder -- and female koalas seem to really dig a baritone.

This research is a big deal: it means the male koala is now the only land mammal we know of that uses an organ other than the larynx to produce sound. Although, really, it's clear that it's using three organs: its larynx, its pharynx...and its heart.