Chaser (dog)

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Chaser in 2013
BreedBorder Collie
Born(2004-04-28)April 28, 2004
Pauline, South Carolina, U.S.
DiedJuly 23, 2019(2019-07-23) (aged 15)
Spartanburg, South Carolina, U.S.
TitleThe Smartest Dog In The World
OwnerJohn W. Pilley

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.

Pilley's wife, Sally, had given Chaser to him as a 76th birthday present. "She came to me when she was eight weeks old and had been with us ever since", she said. "We were playing with her out in the front yard one day, and a red Jeep came flying past us and she went flying out after the car, so we decided to name her Chaser."[1]

In November 2021, Chaser was named the official mascot of Spartanburg Community College, the first mascot in the college's history.[2]


Chaser had the largest tested memory of any non-human animal.[3][4] She was bred by Wayne West at his Flint Hill Farms in Pauline, South Carolina.[5] She was taught by her owner, Wofford College Professor Emeritus of Psychology John W. Pilley, with the formal research published in Elsevier's journals Behavioural Processes and Learning and Motivation.[4][5]

Memory study[edit]

Chaser could identify and retrieve 1,022 toys by name,[5] which was the result of a years-long research effort initiated by Pilley on June 28, 2004.[6] Pilley documents the following milestones as Chaser’s vocabulary grew over time: 50 words at 5 months, 200 words at 7.5 months, 700 words at 1.5 years, and 1,000+ at 3 years.[7]

Chaser began to understand that objects have names at five months of age. At this point, she became able to pair a novel object with a novel name in one trial, although rehearsal was necessary to log it into her long term memory. She recognized common nouns such as house, tree, and ball, as well as adverbs, verbs and prepositional objects.[8] Based on that learning, she and her owner and trainer Pilley continued her training, demonstrating her ability to understand sentences involving multiple elements of grammar, and to learn new behaviors by imitation.[9]

Chaser could also learn new words by "inferential reasoning by exclusion", that is, inferring the name of a new object by excluding objects whose names she already knew.[5][10]

In popular culture[edit]

Chaser and Professor Pilley were featured in the documentary film, Seniors: A Dogumentary, from director Gorman Bechard. The film premiered in March 2020 at the Belcourt Theatre in Nashville,[11] and was released on DVD and pay-per-view in September 2020. Sharon Knolle in MoviePaws called it "a heartwarming celebration of these sweet animals and the people who make sure their last years are spent with a lot of love and comfort."[12]

The two were also spotlighted in a 60 Minutes piece exploring canine intelligence that aired in 2014. [13]


On June 17, 2018, John W. Pilley died in Spartanburg, South Carolina. He was recognized as both a professor and scientist for his research in canine cognition, the latest and most prominent example being with Chaser.[14]

After Pilley's death, Chaser lived with Pilley's wife Sally, and their adult daughters, Deb Pilley Bianchi and Robin Pilley. A year later, on July 23, 2019, Chaser died from natural causes, at the age of 15 years, in her home in Spartanburg, South Carolina.[15] In a Facebook post, the family wrote a tribute to Chaser. "We... were with her as she passed. It was peaceful, beautiful, quiet. She had been doing really well and then a couple of weeks ago, she started going downhill very quickly... She is buried with the other Pilley dogs, sprinkled with John Pilley's ashes."[16]

Deb Pilley Bianchi, who was involved in training and caring for Chaser, has completed a book which she and John Pilley were in the process of writing before he died.[17]

See also[edit]


  1. ^ Lavender, Chris. "World famous dog Chaser dies at 15". Retrieved July 26, 2019.
  2. ^ "Spartanburg Community College's new 'Chasers' mascot encourages students to chase dreams".
  3. ^ Nicholas Wade (January 27, 2011). "Sit. Stay. Parse. Good Girl!". The New York Times. Retrieved 2011-01-18.
  4. ^ a b "Smartest Dog". Popular Science. December 22, 2010. Retrieved 2010-12-27. Psychologist John Pilley of Wofford College in Spartanburg, S.C., wanted to test the boundaries of the canine brain focusing on human language, so he taught Chaser the names of 1,022 toys, one by one, for three years. New Scientist reports that he got her to fetch the toy and then he repeated the name to reinforce her understanding.
  5. ^ a b c d John W. Pilley; Alliston K. Reid (2011). "Border collie comprehends object names as verbal referents" (PDF). Behavioural Processes. 86 (2): 184–195. doi:10.1016/j.beproc.2010.11.007. PMID 21145379. S2CID 18753940.
  6. ^ W. Pilley, John (2014). Chaser: Unlocking the Genius of the Dog Who Knows a Thousand Words. Houghton Mifflin Harcourt Publishing Company. p. 36. ISBN 978-0-544-33459-5.
  7. ^ W. Pilley, John (2014). Chaser: unlocking the genius of the dog who knows a thousand words. Houghton Mifflin Harcourt Publishing Company. pp. 103, 105, 126, 140. ISBN 978-0-544-33459-5.
  8. ^ Pilley, John W. (November 2013). "Border collie comprehends sentences containing a prepositional object, verb, and direct object". Learning and Motivation. 44 (4): 229–240. doi:10.1016/j.lmot.2013.02.003.
  9. ^ Dr. John W. Pilley & Hilary Hinzmann (2014). Chaser: Unlocking the Genius of the Dog Who Knows 1000 Words. Mariner Books. ISBN 9780544334595.
  10. ^ Chaser the Dog Shows Off Her Smarts to Neil deGrasse Tyson, retrieved 2021-03-07
  11. ^ Humbles, Andy. "Mt. Juliet's Old Friends Senior Dog Sanctuary featured in new 'Dogumentary'". The Tennessean. Retrieved 2020-10-07.
  12. ^ "Review: 'Seniors: A Dogumentary' Celebrates Old Dogs and the People Who Love Them". Movie Paws. 2020-09-30. Retrieved 2020-10-07.
  13. ^ "Wofford College professor and his famously intelligent dog featured on 60 Minutes". Upstate SC Alliance. 2014-10-06. Retrieved 2022-12-14.
  14. ^ "Wofford College". Dr. John Pilley, professor emeritus, passes away. Retrieved July 29, 2019.
  15. ^ Derrick Bryson Taylor (July 27, 2019). "Border Collie Trained to Recognize 1,022 Nouns Dies". The New York Times. Retrieved 2019-09-15.
  16. ^ "Chaser the Border Collie". Facebook. Retrieved 2021-08-14.
  17. ^ Pilley Bianchi, Deb (August 2023). For the Love of Dog: The Ultimate Relationship Guide - Observations, lessons, and wisdom to better understand our canine companions. Princeton Architectural Press. ISBN 978-1-797-22330-8.

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