Chaser, a 9-year-old border collie who knows 1,000 words, has given rise to a book by her owner and trainer,
retired Wofford College professor John Pilley.(Photo: Mykal McEldowney, The Greenville (S.C.)
Border collies are herders, bred hundreds of years ago to work with sheep, Pilley said. If a farmer's dog didn't listen to the farmer, the farmer didn't breed the dog. Through selective breeding, border collies gradually began to pay more attention to the words themselves.