How many legs does a kangaroo have? Four, right?
Well, according to new research, the right answer is actually five. Yes, five.
A study published in Biology Letters online Thursday says, when walking on all fours, kangaroos use their tails as a powerful fifth leg to help propel themselves forward.
BBC reports to come to this conclusion, researchers from the University of Colorado Boulder studied five red kangaroos in a lab in Sydney, Australia, and measured the force their tails exerted on the ground.
They found, while the roos were walking on all fours, their tails acted as a fifth leg of sorts, working harder to propel the marsupials forward than their front and hind legs combined. Talk about getting a leg up.
One of the study's authors said in a statement, "We went into this thinking the tail was primarily used like a strut, a balancing pole, or a one-legged milking stool. What we didn't expect to find was how much power the tails of the kangaroos were producing. It was pretty darn surprising."
As National Geographic points out, scientists aren't aware of any other animals that use their tails like this.
The study's authors believe that the kangaroo's use of its tail as an extra leg evolved to make its trademark hop faster and more efficient.
But, as it turns out, walking and hopping aren't the only things the kangaroo's muscular tail is good for.
Red kangaroos are notorious for getting into scuffles with other roos. As Animal Planet notes, during a fight, the animals will deal out some nasty kicks while supporting all of their body weight on its tail.
And LiveScience points out kangaroos' tails help them balance and turn while they're hopping along.
Quite a "tail," right? The study was published in the journal Biology Letters.