Under rocks of the seashore zone lives a small green-grey shrimp called the Pistol shrimp Alpheus sp. One of the nippers is greatly enlarged and has a pit and hammer structure capable of producing a loud snap, frequently heard as you walk around the seashore, or when snorkeling. The loud, sharp sound may warn away predators, or possibly even stun them if they come too close. Some researchers suggest they may use this to stun fish for food. The other nipper is a fine, scissor-like design, excellent for cutting up food.