How we cite our quotes: (Paragraph)
Quote #4
Once, coming around a bend [in the creek], he shied abruptly, like a startled horse, curved away from the place where he had been walking, and retreated several paces back along the trail. (11)
This quote probably comes closer than any other to suggesting that the man has an awareness of his surroundings that might sometimes resemble animal instinct. The comparison with a horse is very telling here, for it is really the only exception to the clear line that the narrator draws between human judgment and animal instinct.
Quote #5
Usually the snow above the hidden pools had a sunken, candied appearance that advertised the danger. Once again, however, he had a close call; and once, suspecting danger, he compelled the dog to go on in front. (13)
The narrator shows here that our man is actually a pretty clever dude. He makes the dog go ahead of him at this moment; but it is important to remember that after he has had his lunch, the man neglects to take the same precaution, and ends up breaking through the ice himself. Perhaps if he'd used the dog the whole way down the creek, he might have avoided the event that would lead to his death.
Quote #6
[The dog] dropped down in the snow and began to bite out the ice that had formed between [its] toes. This was a matter of instinct. To permit the ice to remain would mean sore feet. It did not know this. It merely obeyed the mysterious prompting that arose from the deep crypts of its being. But the man knew, having reached a judgment on the subject, and he removed the mitten from his right hand and helped to tear out the ice particles. (13)
The dog and the man realize that they need to get the ice off the dog's feet. The dog knows this because of the primitive instincts that speak "from the deep crypts of its being" and the man knows this because he has "reached a judgment on the subject." Even the man is capable of learning what to do in such a situation, while the wolf dog has inherited this knowledge from its instinct, which for London is a deeper form of awareness than human judgment—and certainly a more reliable one.