Cephaloscyllium ventriosum, also knon as the swell shark, is found in subtropical waters between the eastern Pacific from central California to the Gulf of California and south to southern Mexico and central Chile. This shark prefers rocky, algae-covered areas near the continental shelves and upper slopes from inshore to deeper waters up to 457 m deep, but most commonly at 5-17 m deep.
Cephaloscyllium ventriosum is a fascinating creature that gets its name for its ability to swallow large volumes of water or air when threatened, which causes the shark to double in size. It inflates its body by bending it into a U-shape while grabbing its tail fin with the mouth. Then the swell shark swallows water or air to deter the predator by its size or by swelling large enough to make pulling it from a crevice a difficult task. Afterward, the swell shark emits a bark-like noise and expels the air or water.
The swell shark feeds on bony fishes, mollusks, and crustaceans. Prey are ambushed near the bottom by the swell shark lying in wait with its mouth wide open. Victims are either sucked in or swept in by the currents.