The non-human animal who has the largest tested vocabulary is a Border Collie named Chaser. Not only does Chaser know many common nouns like tree, ball, and house, she can correctly retrieve by name over 1,000 differently-named toys!

Border Collies are so skilled at agility tests that often in England, they are disqualified from participating in competitions because they are leaps and bounds ahead of other breeds. Competitions include classes for "ABC Dogs" -- "Anything But Collies."

Another brilliant and famous Border Collie named Betsy (who was on the cover of the National Geographic in 2008) knows 15 people by name alone, and is thought to learn as quickly as a human toddler, if not faster.