Of course I know that rabbits hop, but I typically think of that as meaning they hop forward. A few evenings ago, Lisa and I were out for a walk when we spied a couple of the the neighborhood rabbits nibbling on the spring growth in one of the lots along the way. Suddenly one of them hopped straight up in the air, and the other one backed away, laying its ears down flat on its back. The first rabbit hopped straight up again, and the two bunnies sort of circled each other, then separated. The first one did several more of these hops before they both moved on, disturbed by neighborhood children. I assume this was some sort of rabbit dominance stuff, but I'd never seen it myself before. I wish I'd had video to record it.