Dr. Patty Khuly, a veterinarian, suggests that dogs kick after they poop for two reasons. First, they could be covering the poop for sanitary reasons. Second, and perhaps more convincingly, she argues that dogs kick after they urinate and defecate to mark their territory. Dog paws have scent glands that release pheromones. Scratching releases a larger amount of these pheromones, helping your dog mark her territory. In other words, the poopy dance is really your dog’s way of leaving her calling card for the other dogs in the area.
Other experts, including the American Kennel Club, disagree with Khuly about her first theory. They argue that domestic dogs could not care less about covering up their poop, and instead reassert that the real reason dogs kick after pooping is to mark their territory.