Kangaroo
From ResearchID.org, a nexus for researching Intelligent Design
Kangaroo boxing
Kangaroos are fierce fighters, using their forepaws and powerful hind legs to kick. This is called "boxing" and is basically male behavior.
When male kangaroos fight, they look kind of like they are boxing. Standing on their hind legs, they try to knock the other kangaroo off balance. If that doesn't work, the kangaroos stay up on their tails and kick with their hind legs. Male kangaroos usually fought over female kangaroos. The largest male in a group will fight against other males to show and prove that he is the strongest and largest.
