No Pouch Potato: Kangaroos Use Tail As 'Fifth Leg' When Walking

Kangaroos are known as great hoppers, but they don’t do so badly when they’re on all fours, either. That’s because they use their tail as a powerful “fifth leg” when walking, researchers report in a study published in the Royal Society journal Biology Letters. The team videotaped the locomotion patterns of five red kangaroos in a lab in Sydney, Australia. “We measured the forces the tail exerts on the ground and calculated the mechanical power it generates, and found that the tail is responsible for more propulsive force than the front and hind legs combined,” said study leader Maxwell Donelan of Simon Fraser University.

When grazing on grasses, the marsupials move both hind feet forward “paired limb” style while using their tails and front limbs together to support their bodies. “They appear to be awkward and ungainly walkers when one watches them moseying around in their mobs looking for something to eat,” said University of Colorado Boulder Associate Professor Rodger Kram, a study co-author. “But it turns out it is not really that awkward, just weird.”




— James Eng, NBC News