In addition to their females’ pouches, kangaroos are known for their “boxing” skills, and here’s the reason why: Male kangaroos often fight to establish dominance or win a mate. Fights consist mostly of balancing on their tails while trying to knock their opponent off balance. Also: A bit of wrestling. Some background from Wikipedia:
For Kangaroos, Tail Becomes a Fifth Leg.
Winners are decided when a kangaroo breaks off the fight and retreats. Winners are able to push their opponents backwards or down to the ground. They also seem to grasp their opponents when they break contact and push them away. The initiators of the fights are usually the winners. These fights may serve to establish dominance hierarchies among males, as winners of fights have been seen to displace their opponent from resting sites later in the day.