In front of both dorsal fins are hollow, poisoned spikes.  The dogfish's length is 1-1,2 metres and the maximum weight 10 kilogrammes.  It can be found down to 400 metres depth.  It migrates long distances daily, and is very common around Iceland, but rarely found off Greenland.  Each school of dogfishes counts thousands.  It prefers sandy or clay bottoms and temperatures between 6-15°C.

During summer it is very common to the west of the Shetland Islands and off Norway during winter.  Its gestation period is 18-22 months.  Each of the two ovaries contains 1-6 eggs in one bag, which dissolves when the time is right for the fries.  They usually count 4-8 and are 20-33 centimetres long at birth.  They grow slowly and the males reach puberty at 60-80 centimetres and the females at 65-90 centimetres.+

The age of the fish is read from the year rings of the spikes.  Its maximum lifespan is estimated 24 years.  The dogfish feeds mainly of Gadiformes/Anacanthini, herring, eel, and crustaceans.  It often eats fish from line hooks and many fish species shy away when they are preying.

The habitats of the dogfish are the North Atlantic, the South Atlantic, the Pacific Ocean and the South Indian Ocean.  The European annual catch in 2002 was 45 thousand tonnes and this species is considered good food, which is sold under various names in restaurants in Europe.  The liver oil is very rich in vitamin A.