Marty’s photo of the day #2824: Who knew that grizzly bears were terrified of bison? Deb and I watched this mother and her cubs climb down a mountainside and cross a wide field. Suddenly the mother stopped, stood tall, sniffed, and quickly led her cubs in another direction. Moments later, a huge bison came into view and crossed right where the grizzlies had been.

(Photographed in Yellowstone National Park)