In White Fang, innocence is more than the typical naïveté of childhood (or puppyhood in this case). It also indicates a total lack of experience with the world, in which White Fang always finds himself stumbling smack dab against something that's nothing he's ever seen before. White Fang, as an animal, is always innocent in some ways, and that innocence shows up in both physical experiences and emotional feelings. Bet you never thought you'd be asking yourself why wolves can't cry when you started this book.
White Fang's innocence is enhanced by the fact that he's an animal. He can never quite shake it fully.
As a wild animal, White Fang is much less innocent than men.