In Chapter Three, the emergence of the savage nature of Jack becomes apparent. As Jack sniffs the undergrowth and humid earth, he seeks like an animal the feral pigs that roam the island. When a roused bird screams, he shrinks at the cry "with a hiss of indrawn breath." He crounches and becomes little more than "a furtive thing, ape-like among the tangle of trees." Clearly, Jack is reverting in his behavior to a primitive creature as he pushes his way through the forest and nears the lagoon where Ralph stands by a shakily-built shelter, the other is dilapidated.
When Ralph remarks that the other hunters have already returned, Jack tries to explain his compulsion to track down and kill, a compulsion "that was swallowing him up." And, there is a "madness" in his eyes as he speaks. "I thought I might kill." Clearly Jack has become consumed with the primitive excitement of hunting and killing; he is quickly regressing into a savage, rather than the civilized boy that he was back home. He talks of putting a barb on his spear to more easily snare the pig when he casts his spear. However, when Ralph tells him that the lill'uns are frightened at night and, therefore, shelters need to be built, Jack confesses his uneasiness in the forest, saying that he sometimes feels as though something is behind him in the jungle. "Of course there's nothing to it," he adds when Ralph looks at him. "Only I know how they feel. See? That's all," he excuses his weakness. Then, when Ralph mentions getting rescued, Jack "had to think for a moment before he could remember what rescue was" because he has regressed so far in his mind from civilization.