Chaser, a Border Collie, has been shown to have learned the names of 1022 objects. The researchers working with Chaser showed that she not only remembered the names of the objects but was able to understand certain aspects of language.
John Pilley – a master animal trainer – was getting a new puppy in 2004, just as a German study was released on Rico, a dog who learned the names of 200 objects. Pilley decided to find the limits of dog intelligence, and began language training with Chaser when she was five months old. Chaser's training continued for three years under psychologists Alliston Reid and John Pilley.