Nearly a ton each, when wood bison decide to take over a piece of the Alaska-Canada highway, they do. Shooting from the deck of our C-Dory, we found ourselves surrounded by leathery thuds of muscle smacking muscle, the crack of horn on horn, hooves pounding pavement and turf as animals the size of small trucks worked themselves into sprints, snorts, grunts, bellows and the thick odor of bison. We’d been photographing more placid scenes in a herd of about 100 animals – cows and nursing calves, young bulls, grandpa bulls and The Kings – the taut-muscled mature males that stood hands higher than the other members of the herd. Aside from a few younger males occasionally testing each other with head-butts, all was tranquil. The older bulls, hump-shouldered, muscle-ripped massive beasts, grazed peacefully along with the cows and calves or rolled in dust wallows.

The dynamics changed in the blink of an eye. A couple of the big boys started snorting at each other, then locking horns hard and kicking up dust. Suddenly every big bull in the herd, including the largest bull, was on high alert, tails held high, heads lowered as they zeroed in on the point of conflict. Kicking up grass, shrubs, sand and dust, these muscle-sculpted kings moved with impressive speed in their attacks which were aimed at bellies and buttocks as well as heads and shoulders.

Vehicles on the road cautiously edged backwards to give the sparring bison sufficient berth. The motorcyclist seen on the left side of this photo turned around and headed in the opposite direction as the fight edged closer to him.