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. (Via National Geographic)
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.