What lesson does Buck learn about surviving in cold winter nights?

In chapter 2, Buck experiences his first night in the harsh winter environment of the Canadian wilderness. Buck initially attempts to sleep on top of the snow but cannot withstand the cold wind blowing on his body. Freezing, Buck wanders around the camp aimlessly searching for a warm place to rest. Suddenly, the snow gives way underneath his feet and Buck stumbles upon Billee, who is curled into a ball deep in the snow. Buck learns from Billee the important survival skill of digging a hole in the snow and curling up into a ball at night. By burrowing into the snow, Buck's body is not exposed to the harsh winds of the Canadian environment. Throughout the night, more snow piles on top of Buck, and he awakens to the surprise of being buried alive. Buck immediately springs from his hole in the ground and blasts through the thick surface of snow.