Answer: Dog

Chaser, a border collie trained by psychologist Dr. John W. Pilley, has the largest tested memory of any non-human animal. How large? She can identify over 1,000 toys by their name and by the category they have been assigned to by her trainer, and all this in addition to remembering common nouns like “ball” and “tree”.

Further, she can learn new words by inferential reasoning by exclusion—if you give her a basket of old toys with a new one mixed in and ask her to retrieve the new toy with an unknown name, she’ll identify the new toy (and its name) by excluding toys whose names she already knows.

If you ever need to rely on a service animal to help supplement your memory, it would be wise to pick a border collie. Chaser isn’t a one-off anomaly. The other most prominent examples of dog recall are also found in border collies—a fact that should come as no surprise to any border collie owners reading this bit of trivia since the breed is renowned for its drive to learn new tricks and the speed in which they do so.