Fusiform, robust body; snout conical, blunt, with nostrils on sides; mouth large, round; teeth on top jaw triangular, serrated; 5 large gill slits, all before pectoral fin; first dorsal fin large, triangular, origin over rear of base of pectoral fin; second dorsal fin very small; anal fin very small, origin under rear of base of second dorsal fin; tail almost symmetrical, half-moon shaped; tail base very depressed, with large keel that extends onto tail itself.
Back grey-brown, blue-grey, to blackish; abrupt changing to white/pale grey belly; eye black; underside of tips of fins black, usually a black spot where rear edge of fin joins body.
Size: reaches ~ 600 cm.
Habitat: coastal, inshore to oceanic.
Depth: 0 to 1280 m.
Circumglobal, temperate; in our area: Baja and the Gulf of California; Panama to Chile and the Galapagos and Revillagigedos.