During the second evening in the lifeboat, when Pi has seen many sharks around the boat, the hyena goes crazy and attacks the zebra despite Richard Parker's presence. It bites and gnaws it so savagely that it digs into the animal. While Pi watches in silent horror, Orange Juice gives a roar of disapproval.
The hyena's break in behavior—attacking despite the tiger's presence, attacking more savagely than he needed to—foreshadows Pi's own descent into savagery. In addition, the sharks may symbolize what lies outside of Pi's immediate universe, or the safety of the life boat. What lies outside the lifeboat is savage death.