Buck was transformed from domestic to wild after the Yeehats killed Thorton, his master, who had saved him from imminent death at the hands of his former masters. While he was out hunting, the Yeehats attacked their camp and killed Thorton, his partners and the other dogs. Buck arrived to the sight of the dead and the singing Yeehats, who he attacked with so much ferocity that the men scampered for safety in the woods.
Buck remained at the camp until a pack of wolves approached his environment. Members of the pack mounted an unsuccessful attack on Buck, who evaded and fought back decisively. Buck proved his strong nature against the pack members, until one of them who had previously hunted with Buck approached the dog calmly and in a gesture acknowledged Buck. The lead wolf expressed the same gesture and Buck was officially made a member of the pack, henceforth severing ties with his human masters. After this event, Buck went from a domestic to a wild dog, killing Yeehats whenever he met them in the woods.
Then an old wolf, gaunt and battle-scarred, came forward. Buck writhed his lips into the preliminary of a snarl, but sniffed noses with him. Whereupon the old wolf sat down, pointed nose at the moon, and broke out the long wolf howl. The others sat down and howled. And now the call came to Buck in unmistakable accents. He, too, sat down and howled. This over, he came out of his angle and the pack crowded around him, sniffing in half-friendly, half-savage manner. The leaders lifted the yelp of the pack and sprang away into the woods. The wolves swung in behind, yelping in chorus. And Buck ran with them, side by side with the wild brother, yelping as he ran.