A common littoral shark found inshore from the surf zone and in shallow bays to at least 191 m on the outer continental shelves (Ref. 13568). Often on or near the bottom but also occurs in midwater or at the surface (Ref. 247). Only shark known to gulp and store air in its stomach to maintain neutral buoyancy while swimming (Ref. 13568). Found singly or in small to large schools (Ref. 247). Feeds on bony fishes, small sharks, rays, squids, crabs, and lobsters (Ref. 5578). Ovoviviparous, embryos feeding on yolk sac and other ova produced by the mother as well as other siblings in the womb (uterine cannibalism) (Ref. 50449). Usually gives birth to 2 pups after a 9-12 months gestation period (Ref.58048). A migratory species in parts of its range, particularly in its northern and southern extremities where pronounced poleward migration occur in the summer and equatorial movements in autumn and winter (Ref. 247). Usually inoffensive and not aggressive when not provoked (Ref. 247) but has known to bite swimmers and be aggressive towards divers with speared fish (Ref. 6586). Utilized for fresh, frozen, smoked and dried for human consumption (Ref. 247); also for fishmeal, liver oil, fins, and hides for leather (Ref. 13568). Flesh highly appreciated in Japan (Ref. 36731).