In springtime, you'll sometimes see hares chasing each other. They stand up on their hind legs as they jab and kick each other, like a couple of fluffy kick boxers.
This behaviour could be two males (known as Jacks) sparring for dominance in the group, or a female (known as a Jill) rejecting the amorous advances of a male. It's this behaviour which has led to the expression "as mad as a March hare".