Answer: These are two separate answers, if either of them do not help you may delete this.
The sow's head seems to be mocking him, laughing at him. Fear and rage sweep over Ralph. He lashes out at it with bare knuckles and breaks it in two.
At first, Ralph is just puzzled when he sees the pig's skull. Then, he becomes sick and uneasy and in rage, knocks the skull down, splitting it into 2 pieces. He takes the stick out of the ground to use as a possible weapon.