Vertically migrates between the surface and 1,800 ft during the day and surface and 600 ft at night; near islands remains offshore during summer months, but appears to move closer to shore at twilight in the spring, returning to open ocean before sunrise. Oceanic, but may be found close inshore where the continental shelf is narrow. Usually found to at least 150 m. Reported from estuaries. Epipelagic, occasionally occurs in littoral areas. Feeds on fishes (herring, silver hake, white hake, red hake, cod, haddock, pollock, mackerel, butterfish, sea raven and flounders), small sharks, squids, pelagic red crabs, cetacean carrion, occasional sea birds and garbage. Viviparous. Sexual dimorphism occurs in skin thickness of maturing and adult females. May travel considerable distances (one specimen tagged in New Zealand was recaptured 1,200 km off the coast of Chile) (Ref. 26346). Potentially dangerous to humans. Marketed fresh, dried or salted, and frozen; meat utilized for consumption, hides for leather and fins for soup. Sexually mature at 250 cm long and 4-5 years old. The female gives birth up to 80 young measuring 40 cm long, gestation lasts almost a year. Produces from 4 to 135 young a litter