CHASER, a border collie from Spartanburg, South Carolina, the United States, that was widely referred to as “the world’s smartest dog,” has died at the age of 15.

Her owner, retired psychiatrist John Pilley, purchased the black-and-white border collie in 2004 and taught her to learn more than 1,000 nouns, which helped propel Chaser into a worldwide sensation. Pilley died last year, and Chaser had been living with his wife and daughter in Spartanburg.

Pilley trained the dog four to five hours a day for three years. He would display an item, repeat its name up to 40 times, then hide the object and tell the dog to find it. He taught Chaser to understand a grand total of 1,022 nouns using 800 cloth animal toys, 116 balls and 26 frisbees.(SD-Agencies)