southern sleeper shark

A deep-water sleeper shark that is one of the largest sharks and the largest Antarctic fish

The Southern Sleeper shark or Whitley’s Sleeper shark (Somniosus antarcticus) is a deep-water benthopelagic Sleeper shark of the family Somniosidae found in the southern Atlantic, Indian, Pacific, and Antarctic oceans. It is known from depths of 1,312 to 3,937 feet. It has a recorded length if 20 feet.


Family: Somniosidae – Sleeper sharks

Genus: Somniosus 

Species: antarcticus


Phylum– Chordata

Class– Chondrichthyles



Common NameDogfish Sharks

Family– Somniosidae

Common NameSleeper Sharks




Average Size and Length: The Southern Sleeper shark is born 1.31 feet. The maximum length of the Southern Sleeper shark is 20 feet. It is the largest Antarctic fish.

Teeth and Jaw: The upper teeth of the Southern Sleeper shark are spear-like. The lower teeth are slicing with low bent cusps and high roots.

Head: The Snout of the Southern Sleeper shark is short and rounded.

Denticles: The skin is extremely rough. The dermal denticles have strong, hook-like, erect cusps.

Tail: The lower caudal lobe of the Southern Sleeper shark is long, and the upper lobe is short. The caudal peduncle is short and has lateral keels on the base of the caudal fin.

Demographic, Distribution, Habitat, Environment and Range: The Southern Sleeper shark can be found in southern oceans and in the Antarctic. It can be found on the continental and insular shelves from the upper slopes down to at least 3,937 feet. It prefers water temperatures between .6 and 12 degrees C.

Diet: The Southern Sleeper shark is able to catch large, active prey. It will eat invertebrates, fish, and carrion. It feeds primarily on cephalopods, especially the colossal squid, and fish. Its stomach contents have also been found on rare occasion to contain remains of marine mammals and birds. An 11.8-foot-long female caught off the coast of Chile had a whole Southern Right whale in its stomach.

Aesthetic Identification: The Southern Sleeper shark is the largest Antarctic fish. It is gigantic uniform grey to pinkish body and fins. The body is heavy and cylindrical. It has very small precaudal fins. The dorsal fins are spineless, and of equal size. The first dorsal fin is slightly closer to the pelvic fins than the pectoral fins. The distance between the dorsal fin bases is 80% of the snout to the first gill slits and distinguishes it from the Greenland shark and the Pacific Sleeper shark.

Biology and Reproduction: The Southern Sleeper shark is ovoviviparous. It has 10 pups in the uterus of females of 16 feet.

Behavioral Traits, Sensing and Intelligence: The Southern Sleeper shark is epibenthic. Since it is sluggish and slow-moving, and catches active, large prey, the Southern Sleeper shark is thought to be an ambush predator.

Speed: Sluggish and slow moving.

Southern Sleeper Shark Future and Conservation: It is discarded as bycatch by the toothfish fishery.

Southern Sleeper Shark Recorded Attacks on Humans: Not a threat to humans.