Chaser Border Collie 1,022 Toys

Starting in 2004 at his home in Spartanburg, South Carolina, psychologist John W. Pilley trained his border collie, Chaser, in a formal research project. Over several years she learned to identify and retrieve 1,022 toys by name and demonstrate category understanding, earning recognition as the nonhuman animal with the largest tested memory before her death in 2019.

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