A buffalo, also known outside North America as the American bison, is an animal that is often used for pulling or carrying heavy items, as well as for consumption by humans as food.
On March 3, 1850, Marty McFly, Jules Brown, and Verne Brown disguised the DeLorean time machine as a covered wagon. A stampede of buffalo subsequently damaged the time machine.
When Daniel Clayton and Martha O'Brien's wagon train arrived, with various animals carrying the wagons, including horses, mules, and oxen. They let them join the wagon train, and lent them two mules.
When Martha and Verne were trapped by a bear, Doc told them to sit on Old Faithful, using the buffalo hide as insulation to protect them from the heat and steam from the geyser. He then rescued them using a handmade glider, flown by Doc and Daniel Clayton.