Why Does Buck want to join the Wolfpack chapter 7

Buck wants to rejoin his "ancient" family. He wants to run with the wolves, who he sees as his brothers. Buck wants to join them because he is acting on the "call of the wild".

One wolf, long and lean and gray, advanced cautiously, in a friendly manner, and Buck recognized the wild brother with whom he had run for a night and a day. He was whining softly, and, as Buck whined, they touched noses.

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.