Friendship is an expendable entity in the world of the wild. The dogs proceed with caution when making friends with one another, often feeling defensive and on edge about their relationships. Buck does eventually become friendly with the other dogs, but the theme takes a more interesting turn in Buck’s budding friendship with a wolf of the wild. Here we see friendship used as an indicator of Buck’s internal strife. It adds to the turmoil over his decision of whether to stay with Thornton or leave for the wild. Friendship is also used symbolically; that Buck is drawn to a single lone wolf represents his larger desire to be a part of the natural world.
In the main they were the wild wolf husky breed. Every night, regularly, at nine, at twelve, at three, they lifted a nocturnal song, a weird and eerie chant, in which it was Buck's delight to join. (3.27)
Buck has camaraderie with the dogs pulling the sled, but also another parallel camaraderie with the wild wolves. The tension highlights his internal conflict