Kangaroos may have four limbs, two of which being powerful hind legs used for hopping, but new research suggests they use their tail as a fifth leg for grazing.

According to a University of Colorado at Boulder (CU-B) press release, the study was aimed to explore an otherwise boring activity like feeding. The tail helps the animals' front and hind legs propel the kangaroo across the ground as it grazes.

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The CU-B, Simon Fraser University (SFU) and University of New South Wales (UNSW) researchers published their study in the journal Royal Society Biology Letters.

"We found that when a kangaroo is walking, it uses its tail just like a leg," study co-author Maxwell Donelan, an associate professor at SFU, said in the release. "They use it to support, propel and power their motion. In fact, they perform as much mechanical work with their tails as we do with one of our legs."

The Red Kangaroo, the subject of the study, is Australia's largest species of the animal and their feeding may look awkward, but it serves its purpose. The Red Kangaroo uses its hind legs to move forward, but while they lift, the animal suspends itself with its front limbs and tail.

"They appear to be awkward and ungainly walkers when one watches them moseying around in their mobs looking for something to eat," Rodger Kram, a CU-B physiology associate professor, said in the release. "But it turns out it is not really that awkward, just weird.

"We went into this thinking the tail was primarily used like a strut, a balancing pole, or a one-legged milking stool."

He said the evolution of the tail was called "exaptation," meaning its biological function could change over time.

"I'm envious of kangaroos," Kram said. "When they hop faster, they don't use energy at a faster rate. The have the ability to move faster and not get tired, the ultimate goal of a runner."