See Bison at Yellowstone | USA
A line of traffic stops, then the reason walks between the cars: a bison with a shoulder hump level with the bonnet and no interest in anybody's schedule. Yellowstone's herds can fill Hayden or Lamar Valley with dark moving shapes, dust and the grunts of animals that look slower than they are. These are wild descendants of a population that fell to only 23 animals in the park by 1902. Conservation rebuilt the herd, and bison now graze, migrate and shape Yellowstone's grasslands. Their calm appearance misleads visitors; they can run roughly three times faster than a person. Use roadside pull-outs and watch through binoculars or a long lens. Park rules require at least 25 yards (23 metres) between people and bison, and you must back away if an animal approaches; never block the road or leave a vehicle for a closer photograph. Add this to your list and let distance reveal natural behaviour.