Buck's behavior supports the theme "one must lead with a firm hand" through the statement: Buck learns quickly because his teachers are strict and unforgiving.
In the excerpt, Buck’s swift adaptation and improvement in his work under the instruction of Dave and Sol-leks illustrate the effectiveness of a strict and disciplined approach to training. The sharp nips and the backing up of Francois's whip reinforce the idea that firm guidance leads to better learning and performance. Buck recognizes that it is more beneficial to modify his behavior than to face the consequences of his errors, which highlights the significance of strong leadership in his development.