Chaser the Dog Shows Off Her Smarts to Neil deGrasse Tyson

Border Collie Chaser, trained by psychologist John Pilley to recognize over a thousand object names, demonstrates her vocabulary for astrophysicist Neil deGrasse Tyson in this clip filmed before Pilley's death in 2018. It remains one of the clearest public demonstrations of just how much language a dog can actually learn.

Why it's free: Free on NOVA PBS's own channel; GBH produces NOVA for PBS.