Classification of hunting dogs that is more general than setter, retriever, pointer, or other sporting dog categories. Most hounds were bred and trained to track by scent or sight. Scent hounds (e.g., bloodhound, dachshund) are trained to scent in the air or on the ground. Sight hounds (e.g., saluki, Afghan hound) were developed to chase game by sight over long distances. Hounds such as beagles, basset hounds, and foxhounds run in packs; Afghan hounds, borzois, salukis, and others run alone.