There are five species in this order of sharks. They are found in deep waters in the Atlantic, Pacific, and Indian Oceans. Many of the species in this order have six or seven gill slits instead of the normal five gill slits found on most sharks.

Frilled sharks have slim, eel-like bodies and snake-like heads. Cow sharks have stockier bodies and blunt snouts. Both cow sharks and frilled sharks have a single dorsal fin placed well down on their backs and an anal fin. Females give birth to live young. They eat fish, sharks, rays, and crustaceans.