Swell Shark

Swell SharkA catshark living in the Pacific Ocean, the swell shark gets its name from the pretty swell ability to enlarge itself to almost double its size by sucking in air or water.

Swell Shark Scientific Classification

Kingdom Animalia
Phylum Chordata
Class Chondrichthyes
Order Carcharhiniformes
Family Scyliorhinidae
Genus Cephaloscyllium
Scientific Name C. ventriosum


The swell shark is generally 35 inches long but can reach up to lengths of 43 inches. Their heads are flat and broad, with golden eyes with protective third eyelids. Their jaws have 55-60 teeth and tiny gill slits.

These sharks are yellow-brown in coloration, with brown and white spots all over their bodies. Juveniles tend to be lighter than adults.

Where do they live

Swell sharks live throughout the eastern Pacific Ocean, from central California to southern Mexico, as well as off the coast of Chile.

This shark can live up to depths of 457m but generally is present around 5-37m. They prefer algae-covered rock bottoms, hiding in their crevices during the day.



Swell sharks are nocturnal hunters, feeding on bony fishes, crustaceans, and mollusks. They will either lie in wait completely motionless for potential prey or suck up any passing encounters. Swell sharks will scavenge on carrion and look for food in lobster traps.

Swell Shark picture


While generally solitary, swell sharks have been spotted nesting in small groups, some even resting on each other.



If threatened, this shark will form a U shape by grabbing its tail fin with its mouth. It will then proceed to suck in water, swelling up and making it difficult for predators to attack them. This unique behavior gives the shark its name.

Swell sharks can suck in air or water to expand themselves, and releasing air from their stomach makes a bark-like sound.

Swell Shark image


They are oviparous sharks, laying two amber or green eggs after each mating season. The unborn pups feed on the yolk as they gestate for 9-12 months. When they finally hatch, they are self-sufficient and can survive without parental aid.

Initially, they are 5.9 inches long. These sharks can live for around 20-35 years.


This shark’s mottled coloration allows perfect camouflage among the rocky bottoms it inhabits.

Interactions with humans

Swell sharks pose no danger to humans, and they aren’t a primary target of any fishing activities due to their poor meat quality. They are, however, often displayed in public aquaria due to their docile nature.

The IUCN lists the swell shark as “Least Concern” or “LC”.

Recommended Blog Posts

Famous Sharks