The Caribbean reef shark is one of the few sharks able to lie still on the bottom while actively pumping water over its gills, unlike most of its relatives, which must keep swimming to breathe. A key predator on Caribbean reefs, it is now threatened by fishing.
What defines this group — Sharks & Rays
The cartilaginous fish: not a single bone in the body, a skeleton made entirely of cartilage.
A cartilage skeleton, lighter and more flexible than bone.
No gill cover: five to seven gill slits open on the sides or underneath.
Pores on the snout — the ampullae of Lorenzini — pick up the electric field of prey.