Chaser may seem like an ordinary border collie who loves to play, but she has learned over 1,000 words and that's considered the largest vocabulary of any animal ever researched by humans. Her owner, 86-year old retired Wofford College psychology professor, began teaching and training Chaser the game of fetch as a puppy. Over time, those games became sophisticated language lessons. Watch the 60 Minutes segment here and find out more in his book, Chaser: unlocking the genius of a dog who knows a thousand words by John W. Pilley.