A bison cow gives birth to a single reddish-brown calf in the spring. For the first two months of life, calves are lighter in color than mature bison. One very rare condition is the white buffalo, in which the calf turns entirely white.
Perfectly backlit two bison stand on a small rise to catch the first rays of the morning sun in Wyomings Yellowstone National Park. The bitter cold of a long winters night has left the animal encased in a mantle of thick frost.