Answer:
the primitive law of nature
The law of club and fang refers to the primitive law of nature that reigns in the Northland, which rules according to the necessities of survival in reference to both dog's relation to man and to other dogs.
Step-by-step explanation:
Bucks ability to avoid armed men and his ability to defend himself against other animals. These laws are different from bucks former life. He never feared and he always trusted humans.