The North American buffalo, or more properly, the bison, is the largest land mammal on the continent. An adult male bison may stand 6.5 feet at the shoulder and weighs up to 660 lbs. All bison have remarkably acute senses of smell and hearing. They are gregarious, as demonstrated by their desire to live in herds. They usually live to an average age of 25 years, but 40 is not uncommon. Bison are well suited to their environment, they can run fast, swim well and climb steep hills.