Southern Sleeper Shark

The southern sleeper shark is a deep ocean-dwelling species of sleeper shark found in a variety of oceans. Also known as Whitley’s sleeper shark or blimp shark, these sharks belong to the Somniosidae family. They were initially regarded as the same species as the Greenland shark. However, it attained recognition as a separate species in the year 2004.

Southern Sleeper Shark Scientific Classification

Kingdom Animalia
Phylum Chordata
Class Chondrichthyes
Order Squaliformes
Family Somniosidae
Genus Somniosus
Scientific Name Somniosus antarcticus


The southern sleeper shark grows to an average length of 14 feet. However, their length can grow up to 20 feet at a maximum. Like most sleeper shark species, their body color varies from dark gray to dark brown.

They have short, rounded snouts. The upper jaw consists of sharp, spear-like teeth, while the lower teeth have higher roots and cusps that are bent low.

The shark has a heavily set, cylindrical body with highly rough skin. Their dermal denticles (teeth-like strong coverings on shark’s bodies) have erect cusps, which are strong and look like hooks.

The precaudal fin is small, while the first and second dorsal fins are of a similar size, devoid of spines though. Their first dorsal fins lie close to the pelvic fin and are far from the pectoral fin.

Where do they live

Endemic to Australia and New Zealand, these sharks have a wide distribution occupying the southwest Indian Ocean and southeast and the southwest Pacific Ocean. They can also be found in the Antarctic Ocean.

They inhabit continental and insular shelves in depths of 1312-3608 feet. They prefer living in water temperatures of 33.08-53.6 °F.



They mainly prey on cephalopods (giant and colossal squids) and fish. Their stomach contents may even contain remains of birds and marine mammals, which is less common.
In a rare incident, a female shark measuring 12 feet, caught along the Chilean coast, had ingested an entire southern right whale dolphin.


The reproduction mode in the southern sleeper shark is ovoviviparous. The eggs hatch inside the parent’s body and are sustained by the egg yolk remains.  The females give birth to a litter containing around ten pups, each measuring around 1.3 feet.


The small-sized fins of these sharks make them sluggish. However, the prey they catch is big. Hence, they are considered ambush predators who capture their foes from a hidden location. Their color helps them camouflage with their surroundings and quickly get after their prey.

Interactions with humans

The Department of Conservation in New Zealand has listed the southern sleeper shark as ‘Not Threatened’ with additional parameters such as ‘Data poor’ and ‘Uncertain whether Secure Overseas’ under the New Zealand Threat Classification System.

Their widespread population and lack of valid threats to their numbers have led to the IUCN classifying these sharks as a ‘Least Concern’ species.

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