Bull Bison Sniffing The Air, Searching For Females In Heat. Stock Image

Randy bull buffalo snorting and bellowing as he searches for a mate among a small herd of females and calves along the road near Black Tail Plateau, in Yellowstone National Park. Close cropped grasses indicate its time to move to lower elevations for greener pastures and meadows along one of the major rivers in the Park. Early September coats on the Bison's back are heavier as they prepare for the coming winter.