Koalas’ Rumbling Roars Don't Match Their Cuddly Appearance

From venomous snakes to crocodiles, Australia is teeming with dangerous wildlife. But if you hear a bellow that sounds like a cross between a wild boar and T.rex while exploring the outback, don’t panic. You may be hearing a koala bear trying to attract a mate.

Koalas possess one of the greatest discrepancies between sound and appearance in the animal kingdom. Rarely weighing more than 30 pounds, they more closely resemble stuffed animals than the massive bears they’re misnamed for. But when they open their mouths, you can hear how someone might confuse them with a grizzly. The koala’s rumbling brays are 20 times lower than the typical call for an animal its size, according to National Geographic. The sound is so intimidating that sound designers sampled it when mixing the T.Rex’s iconic roar for Jurassic Park (1993).

Koalas possess unique vocal cords that allow them to belt their baritone mating song. Separate from their normal, koala-sized larynx, they have a second, supersized set of vocal folds that have evolved to produce deep tones. In the video below, you can listen to a male koala showing off his brassy pipes after arriving at his new home in an Australian animal park.

The sound koalas make may be surprising if you only know the species from cute pictures on the internet. If you’re familiar with their aggressive tendencies, the roar should feel more fitting. Koalas have been known to attack dogs and people who encroach on their environment. Here are more facts about the feisty tree-huggers from down under.