Who is Buck's first owner after being sold?

Buck's first owner after being sold is Perrault, a mail courier. When Buck is sold, he is taken to the Yukon Territory during the gold rush, where he begins his new life as a sled dog. Perrault, along with Francois, is responsible for training and caring for Buck and the other dogs in the team. Perrault's role as a mail courier is significant because it introduces Buck to the harsh realities of life in the wild and the demands of being part of a sled dog team.

Under Perrault’s ownership, Buck learns to adapt and tap into his primitive instincts, which are crucial for his survival in the challenging environment. This period is essential as it marks the first step in Buck's transformation from a domesticated pet to the wolf-like creature he eventually becomes. This experience shapes his character and lays the foundation for the significant changes he undergoes throughout the story.