Buck is unable to sleep on his first night on the trail  because it is so cold.  Used to spending the night indoors, he first tries to enter the tent set up for Perrault and Francois, which "glow(s) warmly in the midst of the white plain", but the dog is quickly and unceremoniously "bombarded...with curses and cooking utensils...till he...(flees) ignominously into the outer cold".  Banished to the freezing elements, Buck feels he has no other option but to lay down in the snow, "but the frost soon (drives) him shivering to his feet".  Buck wanders miserably among the many tents for a time, but finds that "one place (is) as cold as another".  Finally, he seeks out his team-mates on the line, but finds "to his astonishment, (that) they (have) disappeared".  As he searches for them, the snow beneath his feet gives way, and when he sinks down into a neat and warm cavern, he discovers Billee, one of his fellow sled-dogs, "curled up under the snow in a snug ball".  Buck is a quick learner, and, having found out how the other dogs do it, immediately commences to dig a hole for himself and settle himself within it - "in a trice the heat from his body fill(s) the confined space and he (is) asleep" (Chapter 2).