Where temperatures fall so low that even the trees can freeze and explode, the flora and fauna of a certain forest in Japan's northernmost island of Hokkaido have evolved clever and curious ways to survive the cold. Squirrels rely not just on memory but also on an enhanced sense of smell to locate their stashes of nuts under the snow. A particular species of woodpecker carves a deep, roomy hole in a dense white pine for a nest, feasting on the ants it somehow knows are inside. And a coniferous tree native only to this region has devised an ingenious way of self-defense. The question is not how cold is cold, but how to exist in spite of it all.