The sight of two American bison locked in a head-clashing battle for dominance is enough to stop just about any tourist in their tracks – especially when the skirmish takes places in the middle of a snow-covered road in the white haze of winter. John Clark was on a recent adventure in Yellowstone National Park when he came across these bison throwing down and stopped to film the brief brawl:

Bison typically spar like this during the peak rutting season which lasts from June to September each year. It's unclear if these males decided to start things off early or if they are simply practising their head-knocking skills in preparation of the breeding season when exchanges with other males are frequent. 

Bison bulls are polygynous, so they will mate with multiple females during the rut. The action usually kicks off in June or July when mature males start mingling in mixed-sex herds in search of mating opportunities. Bellows can be heard across the landscape as male behaviour becomes entirely geared towards mating. 'Wallowing sessions' in which bulls roll around violently as a display of aggression can mask an entire herd in a thick cloud of dust. When a male finds a receptive female he will do his utmost to keep other bulls at bay.

Much of the bulls' behaviour during the rut is just for show and actual, significant fights are rare, though they do occur if intimidation tactics fail. In the case of this snowy showdown, it's likely that the fight ended without serious injury.


Top header image: Tupulak, Flickr