Bison, symbolic animals of the Great Plains and have also been called buffaloes. By any name, they are massive beasts and the heaviest land animals in North America. Bison stand some 5 to 6.5 feet tall at the shoulder, and can tip the scales at over a ton. Despite their massive size, bison are quick on their feet. When the need arises they can run at speeds up to 40 miles an hour. That's a lot of animal coming at you surprisingly fast.