A Yellowstone winter is a brutal one. With temperatures that plunge down to minus 40 degrees Fahrenheit the wildlife has to find strategies to survive. Some animals leave, some hide and some tough it out. Grizzlies hunker down and hibernate, but this winter the temperatures have been erratic and some bears are emerging early. Finding food is a huge challenge, but our camera crews follow one male who's lucky enough to hit the jackpot and find a bison that's been released from its icy tomb down in the valley. But he has to hang onto it while the scavengers hassle him. Great Gray owls suffer as their prey hides under an icy layer of snow that proves almost impossible to break through. Will this lack of food affect their mating and ability to raise a family in the Spring? Cameraman Jeff Hogan is following them to find out. And top wolf biologist Doug Smith explains why he's concerned about the number one predator. With a winter that's had less snow than usual it's favored the prey and the wolves are starving hungry. Host Kirk Johnson who's the Sant Director of the National Museum of Natural History in Washington, visits this unique wilderness to unravel the story of this particular winter in Yellowstone.