I don't know. In Herzog's "Happy People: A Year in the Taiga," you see a dog keeping up with a snowmobile at a constant pace for several hours. (Edit: the dog r

I don't know. In Herzog's "Happy People: A Year in the Taiga," you see a dog keeping up with a snowmobile at a constant pace for several hours. (Edit: the dog ran 150 kilometers nonstop at a snowmobile's pace)