No other animal is as defined by the long history of its codependency with humans as the dog, so much like us in its capacity for affection and savagery. All dogs trace their ancestry to one canine—the wolf—but you’d never know it looking at Chihuahuas, Bedlington terriers, Belgian griffons, cocker spaniels, Great Danes, boxers, Basenjis, Afghan hounds, or corgis. Over the centuries, we’ve bred dogs for all sorts of jobs and sports: long dachshunds to squirm down badger holes, balloon-chested greyhounds and whippets to race, Entlebucher Mountain Dogs to herd sheep. Lapdogs abound in a fantasia of shapes and colors. Or one can choose a companion dog by intelligence, disposition, or possibly endearing neuroses (tail-chasing, for example). Our feats of selective breeding produce trendy, aesthetically pleasing dogs, including many so inbred that they suffer from about 350 known hereditary diseases, including beagles with weak spinal discs, Dobermans given to narcolepsy, basset hounds with blood-clotting woes, flat-faced Pekingese bedeviled by breathing problems, and Scottish terriers eighteen times more likely to develop bladder cancer.
