As he puts on his war paint for the hunt, Jack explains that, like an animal, he wants to camouflage himself, and, not being able to come up with a better simile, likens himself and the other hunters to "moths on a tree trunk."
The hunt symbolizes the descent away from civilization into a form of being more primal, atavistic, and animalistic.
Jack paints a black slash on his face with charcoal, which is like an animal's stripes. When he looks at himself, he sees not "himself but at an awesome stranger."
Even Ralph is tempted toward animalism of the hunt as he accepts the cooked pig meat and "gnawed it like a wolf."
The boys then replay the hunt, with Maurice playing the part of the pig:
Maurice pretended to be the pig and ran squealing into the center, and the hunters, circling still, pretended to beat him.
The boys are more like animals as they give up reason and give into to their more irrational, id-like passions, living in the moment and not thinking about the future, as letting the fire go out symbolizes. Golding uses animalistic imagery to emphasize this point.