Question for Chapter 4 of Call of the Wild

Including Dave's death in the story further illustrates the loyalty and dedication of the dogs. It doesn't matter to Dave that he is weak and in horrible pain.... to be removed from the traces is to kill him before his time. Buck's dreams of ancient times suggest that a dog's passion for work may be related to it's desire for an existence similar to that ancient existence. Dave "pleads" with his eyes to remain with the team. Dave seems to understand that when his ability to work ends, his life ends, for a life without labor is no real life. Once again the reader must be reminded of Buck's earlier existence. No matter how coddled he was, London appears to be suggesting that Buck must be happier in his present life.