how does buck change?

From the start of the novel through the third chapter, Buck goes through enormous changes. He is taken from an idyllic home, where he is pampered and treated like a king, to a ship where he is cages and beaten. He learns to mistrust, he learns to hate, and he is broken by abuse. Buck is forced to fight for position, he is attacked by other dogs, and he must learn to fight back in order to survive. He becomes a self-confident, tenacious, leader.