How does Jack represents our animal instincts?

Jack is the first to seriously overstep the boundaries of civilized society. His attempts to become a successful hunter are in effect attempts to succumb entirely to his animalistic nature. His painted face, reminiscent of some less developed societies, supposedly makes him indistinguishable from the animals of the forest. When Jack finally does kill a pig, as he has intended to do since the beginning of the novel, he fulfills a violent blood-lust that, until then, had remained frustrated. The other hunters share this quality; when they dance and sing about killing the pig, they show that they have succumbed to the thrill of violence. They relish the slaughter, an enjoyment that transcends pride and signifies pure lust. As they cheer on the means by which they mutilate the pig, their painted skin, chanting, and frenzy suggest they have developed their own sub-society, one based on rituals and an almost spiritual worship of blood, violence, and slaughter.