What does London suggest when he writes the dog did not know anything about thermometers?

When London writes that the dog did not know anything about thermometers, he suggests the limitations of animal understanding and the instinctual nature of dogs. This highlights the disparity between human knowledge and animal instinct, emphasizing that the dog operates on its innate senses rather than abstract concepts. It underscores a theme of the story, showcasing the raw, unfiltered reality of survival in nature, where practical survival instincts often supersede intellectual comprehension.