In Back to the Future, what is Doc Brown’s dog called?

In Back to the Future, Doc Brown’s dog is called Einstein.

Einstein is Doc Brown’s shaggy Old English Sheepdog and appears in the film’s opening experiment at the Twin Pines Mall. Doc uses the dog to demonstrate that the DeLorean time machine can transport living matter through time. Einstein is placed inside the car for a one-minute trip into the future, returning safely one minute later.

The name is a reference to Albert Einstein, the German-born physicist whose theories of relativity transformed modern physics. Doc’s choice of name also fits the film’s emphasis on science, experimentation, and time travel.

Einstein is sometimes confused with Copernicus, the black-and-white cat seen in the opening scenes. Copernicus belongs to Doc as well, but Einstein is the animal used in the first time-travel test.