Chaser 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.
Background
Chaser had the largest tested memory of any non-human animal. She was bred by Wayne West at his Fleet Hill Farms in Pauline, South Carolina. She was taught by her owner, Wofford CollegeProfessor Emeritus of Psychology John W. Pilley, with the formal research published in Elsevier's journalsBehavioural Processes and Learning and Motivation.
Memory study
Chaser could identify and retrieve 1,022 toys by name, which was the foundation for her vocabulary. She 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 only 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. Based on that learning, she and her owner and trainer Pilley continued her training, demonstrating her ability to understand sentences with multiple elements of grammar and to learn new behaviors by imitation. 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.
Deaths
Pilley's death
On Sunday, June 17, 2018, John W. Pilley, died in Spartanburg, South Carolina. A professor and a scientist, he was recognized for his research in canine cognition, the latest example being with Chaser. After Pilley's death, Chaser lived with her former owner's daughters, Deb Pilley Bianchi and Robin Pilley, as well as his wife, Sally Pilley. Deb Pilley Bianchi is completing a second book that she and John Pilley were writing before he died, which has a working title of "A World of Chaser's".
Chaser's death
On July 23, 2019, Chaser died from natural causes, at the age of 15 years, in her home in Spartanburg, South Carolina. Just prior to Pilley's 76th birthday, his wife had given Chaser to him as a present. "She came to me when she was eight weeks old and had been with us ever since", Sally Pilley 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."
