If you ask a dog lover about Back to the Future, they’re sure to mention Doc Brown’s loveable dog, Einstein. Einstein actually plays a significant role in the Back to the Future films, since he was technically the first known time traveler in the world—it is Einstein who Marty and Doc Brown watch go back in time and return, unharmed, prompting Doc Brown to believe that sending people back in time was now safe as well. If you’re a fan of Back to the Future, movie dogs, or even just movie trivia, read on for some interesting and surprising facts about “Einstein” from the Back to the Future series.

Einstein was played by two different dogs

In the first Back to the Future film, Einstein was played by a dog named Tiger, who had been trained by Hollywood animal trainer Richard Calkins. However, when it came time for the character to appear in Back to the Future 2 and back to the Future 3, Calkins found that Einstein had simply grown too old to handle the rigors of filming a movie. He brought in younger dog that resembled Einstein called Freddie, to play the role instead. Freddie played Einstein for both Back to the Future 2 and 3.

Einstein-image Nobody knows what breed Einstein is

The exact breed of Einstein is unknown, and trainer Richard Calkins has never revealed Freddie or Tiger’s exact breed. Some fans think that he may be a Berger Picard, or a Briard with uncropped ears; other suggestions include some type of sheepdog or even simply a mixed-breed dog.

Einstein becomes a major character in the cartoon

In the animated series based on Back to the Future, Einstein goes from helpful sidekick to a major character. However, the animated version of Einstein doesn’t resemble his film counterpart. In addition to the aesthetic change, Einstein is noticeably smart in the animated series, and even helps out Doc Brown with his many inventions. However, Einstein doesn’t actually talk in the cartoon.

Einstein was voiced by Danny Mann in the animated series

In the animated series, actor Danny Mann provided the vocal performance for Einstein. Mann is well known for his voice acting work, which has included other animal characters such as Percy the dog in Disney’s Pocahontas, two roles in the Land Before Time film series, and Strongheart in Lady Lovely Locks.