Bunnies have very few defenses. Aly is right on about the thumping....it is a warning to others that something isn't right or there's a danger "out there"... It's also a warning to animal or person they see as the threat to stay away from this Big, bad and mean bunny...LOL!!!!!

Every once in a while one of my guys will haul off with a few thumps and nothing is there...who knows what they think they are seeing as a threat..... I wouldn't ignore the thumping, I would check out to be sure nothing is threatening him but it certainly is nothing to be afraid of.