If a human companion is not actively involved, is it actually a sport? Take greyhound racing, for example, or hunting from a duck blind, from which the dog retrieves the game.
Is 'any' activity a sport if a casual observer does not understand the nature of the competition? For example, in a conformation show, the handler and dog move around a ring for a judge to evaluate the dog's appearance and structure; the skill and knowledge required are not obvious to those uninterested in the sport.
This list is intended only to represent anything that anyone is likely to refer to as a dog sport, not to argue its validity as sport.