An incredibly rare white bison calf has been photographed in Yellowstone National Park, exciting Native American tribes who view its arrival as a religious prophecy heralding major change.

It was spotted in the Lamar Valley area of the park, making it the first white bison to be born from the last wild herd in the US, according to modern records.

The birth of a white buffalo is a sacred event for many Native tribes of the Great Plains, including the Lakota people, who believe that it relates to a time around 2,000 years ago when food was scarce and the bison were rarely seen.

The Lakota legend tells of a beautiful woman who appeared and delivered the gifts of a sacred pipe and bundle to the people. The woman told them she would return to restore harmony in a troubled world, and then rolled on the ground four times, changing colour each time before becoming a white buffalo calf.

Her departure led the bison to return, and white buffalos are now seen as a sign that prayers are being heard and that change is coming.