Why does Jack seem unconcerned that they missed signaling a ship when he returns with the first pig he kills?

In chapter 4, Ralph leads his hunters on an expedition and excuses Samneric from the duties of maintaining the signal fire on the top of the mountain. While Jack is out hunting pigs, Ralph and Piggy spot a ship passing the island and look to the top of the mountain to discover that there is no smoke coming from the signal fire. Ralph thinks about climbing the mountain but realizes that he doesn't have Piggy's specs to light the fire when he reaches the top. As the ship continues to sail away, Ralph is overcome with anger, frustration, and a loss of hope. Ralph then laments about missing the rare opportunity to be rescued while Jack and his hunters march onto the beach with a dead pig chanting, "Kill the pig. Cut her throat. Spill her blood" (Golding, 52). When Jack and his hunters arrive on the beach, he cannot wait to tell Ralph the story of how they killed their first pig. Jack completely ignores Ralph's comments about letting the signal fire go out and enthusiastically describes their exciting hunt. Jack is more concerned with hunting and killing pigs than he is with establishing a civilized society or being rescued, which is why he is not concerned that they missed the passing ship. Overall, Jack is more excited about successfully killing their first pig and is less upset about losing an opportunity to be rescued.