What happend to the dog in chapter two

It took him awhile to realize that the dogs could teach him how to trap. But he had to understand their cadence, their walk, as small variations in the snow and their food could affect their performance. They must be fed meat and fat and not dry dog food.

Paulsen learned this lesson the hard way when his dog Storm started spraying blood out of his rear end. He was screaming and lunging, ignoring his condition. Paulsen was frantic and let him loose but Storm quickly went insane when separated from the team and would not depart from his ways with the team. So Paulsen allowed this and the team took him forward another seven hours and was nothing to him. He did not die and never faltered and not for many years after that. Paulsen always wanted to know everything about his dogs.