Chaser, known to some as “the world’s smartest dog,” died on Tuesday, July 23, 2019 at the age of 15. The late John Pilley, formerly a psychologist at Wofford College, trained Chaser to tend a “herd” made up of more than 1,000 toys and remember the name of each item in the pile. In 2009, NOVA visited Chaser to test her vocabulary.

John has taught Chaser to tend an extremely large “herd,” but there are no real sheep in it. Chaser’s herd is made up of toys, about a thousand of them.

Chaser (April 28, 2004 – July 23, 2019) was a Border Collie with the largest tested memory of any non-human animal. Chaser worked with Professor John W. Pilley, at his home in Spartanburg, South Carolina, from eight weeks old, until Pilley’s death in June 2018. Pilley spent that time training her in a formal research project. Chaser could identify and retrieve 1,022 toys by name.


John Pilley, who owned and trained the world-famous border collie Chaser to know more than a thousand words, died Sunday in Spartanburg.

He was diagnosed in late April with leukemia and would have been 90 years old on July 1. Pilley was a scientist who conducted research in canine cognition and a professor emeritus of psychology at Wofford College. He retired from Wofford in 1995 but remained active in campus activities.



Training Chaser was his most notable achievement as Chaser could recognize 1022 words or items.