Swell Shark

Cephaloscyllium ventriosum

The swell shark (Cephaloscyllium ventriosum) is a small, docile catshark reaching about 1 m found in the eastern Pacific from central California to southern Mexico and Chile. It has a flattened head, mottled brown and tan patterning with dark and light saddle markings providing excellent camouflage. When threatened, it curls into a U-shape, grabs its tail fin with its mouth, and swallows water to inflate to nearly double its normal size, wedging itself tightly into crevices. It is biofluorescent, glowing bright green under ultraviolet light. A nocturnal species, it is commonly found resting in rocky caves and crevices during the day by divers in California kelp forests.