; subclass Elasmobranchii, order Lamniformes)
A small family of marine sharks that have stout, streamlined bodies. The first dorsal fin is placed midway on the back, but the second dorsal and anal fins are small and near the tail fin. Distinct ridges (keels) are present on each side of the caudal peduncle. Among the species considered dangerous are Carcharodon carcharias (white shark), 6.4 m, and Isurus oxyrinchus (mako shark), 3.6 m. The very large Cetorhinus maximus (basking shark), 10 m, is a harmless animal. Some workers place certain species in different families. There are about 14 species, distributed world-wide.
Subjects: Zoology and Animal Sciences.