How is Mercedes different from Hal and Charles in The Call of the Wild? Mercedes is soft-hearted and sympathetic toward the dogs, while Hal and Charles are quick-tempered and cruel. Mercedes understands how to best care for the dogs, while Hal and Charles do not understand them at all. Mercedes packs the sled with only necessary items, while Hal and Charles insist on bringing all of their possessions. Mercedes is experienced at traveling in the harsh environment, while Hal and Charles make many mistakes.