The swell shark lives in the kelp forest, along rocky areas where algae is present. It's small (less than four feet) and brownish in color. It has a stout body, a flattened head with large oval eyes, a short snout, and very wide mouth. Its mouth is filled with lots of tiny teeth.
The swell shark is nocturnal and eats mainly small fish and any prey it can easily swallow. It will sometimes invade lobster traps for an easy meal. However, it's not dangerous to people.
Like the horn shark, the swell shark lays eggs. Unlike the horn shark, its egg case doesn't look like it's from a machine shop. The swell shark egg case looks like a drawstring purse, and is sometimes called a mermaid's purse. After seven to ten months, the egg case hatches, and, as you can see in the photograph above, the swell shark pup emerges.
It's called a swell shark because it can pump water into its stomach, causing its body to "swell up." This makes it difficult to pull out from between rocks, or for bigger fish to swallow it.