Pacific sleeper shark | |
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Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Chondrichthyes |
Subclass: | Elasmobranchii |
Order: | Squaliformes |
Family: | Somniosidae |
Genus: | Somniosus |
Species: | S. pacificus |
Binomial name | |
Somniosus pacificus Bigelow & Schroeder, 1944 |
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Range of the Pacific sleeper shark |
The Pacific sleeper shark (Somniosus pacificus) is a sleeper shark of the family Somniosidae, found in the North Pacific on continental shelves and slopes in Arctic and temperate waters between latitudes 70°N and 22°N, from the surface to 2,000 metres (6,600 ft) deep. Records from southern oceans are likely misidentifications of relatives. Its length is up to 4.4 m (14 ft), although it could possibly reach lengths in excess of 7 m (23 ft).
Pacific sleeper sharks, which are thought to be both predators and scavengers, can glide through the water with little body movement and little hydrodynamic noise, making them successful predators. They feed by suction and cutting of their prey. They have large mouths that can inhale prey and their teeth cut up any pieces that are too large to swallow. They show a characteristic rolling motion of the head when feeding. Only in Alaska has the shark's diet been studied - most sharks' stomachs contain remains of giant Pacific octopus. They are also known to feed on bottom-dwelling teleost fishes, as well as soles, flounders, Alaska pollock, rockfishes, shrimps, hermit crabs, and even marine snails. Larger Pacific sleeper sharks are also found to feed on fast-swimming prey such as squids, Pacific salmon, and harbor porpoises. The diet of the Pacific sleeper shark seems to broaden as they increase in size. For example, a 3.7-m female shark found off Trinidad, California was found to have fed mostly on giant squid. Sleeper sharks found in Alaskan waters from 2 to 3 m (6.6 to 9.8 ft) seem to feed mostly on flounder, pollock, and cephalopods, while sleeper sharks 3.3 to 4.25 m (10.8 to 13.9 ft) long seem to consume teleosts and cephalopods, as well as marine mammals. A recent study in the Gulf of Alaska suggests that sleeper sharks may prey on juvenile Steller sea lions.