Also called blowfish or swellfish, the puffer gets these names from its ability to inflate its body with air or water. When alarmed or even touched, the puffer uses a special sac that is a ventral extension of the stomach to quickly expand to a very large size, protecting it from enemies. When left alone, it soon deflates. Puffers inhabit bays, estuaries and protected coastal waters, eating primarily shellfish and an occasional finfish. Unlike some of its cousins, the meat of the northern puffer is non-toxic.