The Greenland shark lives off the coast of Greenland, where it spends most of its life sleeping. Researchers recently discovered that these sharks sleep about 20 hours per day, making them the longest-sleeping fish in the sea. They are able to do this because their body temperature drops during sleep, allowing them to conserve energy while conserving heat. This makes sense since the water around Greenland is constantly cold, even during summer months.
Sleeper Shark Scientific Classification
The International Union for Conservation of Nature (IUCN), an international conservation organization, announced earlier this week it had classified the sleeper shark as critically endangered. This classification makes it illegal to catch the species without a permit.
The IUCN classified the shark under the category of “vulnerable.” The group says there are fewer than 10,000 sleeping sharks left in the world.
This is the third classifications change since the IUCN began tracking the species in 2007. In 2011, the group listed the species as vulnerable, while in 2013, it changed the status to near threatened.
Sleeper Shark Conservation Status
The International Union for Conservation of Nature (IUCN) announced that there are no known threats to the survival of the sleeper shark. This makes it one of the most secure sharks in the world.
This species lives on the ocean floor where it spends most of its life sleeping. They usually sleep during daylight hours, but some individuals do go into hibernation during the winter months.
They feed primarily on fish, squid, crabs, octopuses, sea stars, shrimp, clams, and small invertebrates. During mating season, males will bite off pieces of females’ skin to mark territory. Females use their teeth to scrape away the male’s markings.
The IUCN lists the sleeper shark as being “Least Concern.”
3 Incredible Sleeper Shark Facts!
The sleeper shark is one of the most mysterious creatures in the ocean. While we know a lot about how they live, there are still many things unknown about this elusive fish. Here are three facts you probably didn’t know about the sleeper shark.
1. They Are Cold Blooded
In the summertime, sleeper sharks prefer warmer temperatures, but they can tolerate colder ones during winter. This makes sense because they spend most of their lives in the dark abyssal zone of the ocean, where it gets very cold.
2. They Can Survive In Deep Water
This shark spends most of their time in the deep sea, but some species have been known to make short excursions into shallower waters. When they do come up to the surface, they tend to hang out near the shoreline.
3. They Have An Anti-Freezing Protein
Like humans, sharks produce antifreezes to keep their bodies cool. These proteins allow them to withstand freezing temperatures without becoming sick. Scientists think that the same thing happens in sleeper sharks, too.
Sleeper Shark Classification and Family
The Somniosidae are a group of sharks that includes the great white, tiger, bull, nurse, hammerhead, smoothhound, megamouth, and blacktip reef sharks. They are known as sleeper sharks because they typically spend most of their lives asleep near the ocean floor. Most species feed on fish and invertebrates, although some eat crustaceans and mollusks. Their diet varies depending on location. Some species eat plankton while others prefer larger prey items like squid and octopus.
Sleeper Shark Species
There are around 20 recognized species within the family of sleeper sharks, spread over six different genera. These are the most well known species:
Greenland Shark: Found throughout the North Atlantic and Arctic oceans, the Greenland shark has been recorded living up to 200 years.
Pacific Sleeper Shark: Native only to the North Pacific Ocean, including Japan and California, this is another larger and better-known species.
Based on the rate of growth and size, it’s believed to live between 250 and 500 years old.
Sleeper Shark size and Appearance
The sleeper shark differs greatly depending upon where it lives. In warmer waters, such as off Australia, the Atlantic Ocean, and the Caribbean Sea, the species grows much larger than those found in cooler regions like the Gulf of Mexico, the Mediterranean Sea, and the North Pacific. These warm water populations typically grow to lengths of 10 to 15 feet long, while cold water dwellers can reach lengths of 25 feet.
In terms of appearance, the typical species is characterized by a rounded snout, two small dorsal fins with spines at the base, and a single row of bony teeth along the upper jawline. A dark band runs down the center of the head, and another extends around the eyes. The skin ranges from grayish to brown, although some individuals exhibit variations in coloration.
Distribution, Population, and Habitat
Sleeper sharks are among the most mysterious animals on Earth. They spend much of their lives hidden beneath the ocean floor, emerging only to feed. Their existence has long eluded scientists because of their remote habitats and secretive behavior. But now, researchers have documented the distribution, population size, and habitat preferences of three sleeper shark species—the Atlantic sleeper shark, the Pacific sleeper shark, and the Greenland shark—in the North Atlantic Ocean and the Southern Hemisphere.
The study, published today in PLOS ONE, revealed that the number of sleeping sharks living off the coasts of Greenland, Canada, and New Zealand has declined over the past four decades. In addition, the study showed that the Greenland shark prefers colder waters than the other two species. These findings suggest that the Greenland shark could face further threats due to climate change.
Pacific Sleeper Sharks, Somniosus pacificus
The Pacific sleeper shark, Somniosuspacificus(Bigelow and Schroeders, 1944), is a large deep water shark reaching lengths of up to. This species has been reported from depths of, but most specimens have been caught near the surface.
This shark occurs in coastal waters off Japan, Korea, China, Taiwan, Indonesia, Malaysia, Australia, New Zealand, Chile, Peru, Argentina, Uruguay, Brazil, Colombia, Costa Rica, Panama, Venezuela, Trinidad and Tobago, Nicaragua, Mexico, Cuba, Honduras, El Salvador, Guatemala, Belize, Jamaica, Bahamas, Bermuda, Turks and Caicos Islands, United States, Canada, Greenland, Iceland, Norway, Sweden, Finland, Denmark, Germany, France, Spain, Italy, Portugal, Malta, Greece, Cyprus, Turkey, Israel, Lebanon, Syria, Jordan, Saudi Arabia, Kuwait, Oman, Qatar, Bahrain, UAE, Yemen, Egypt, Sudan, Chad, Niger, Nigeria, Senegal, Ivory Coast, Ghana, Togo, Benin, Cameroon, Central African Republic, Congo, Gabon, Angola, Namibia, Botswana, Zimbabwe, Zambia, Malawi, Mozambique, Swaziland, South Africa, Lesotho, Eswatini, Libya, Tunisia, Algeria, Morocco, Mauritania, Western Sahara, Comoros, Mayotte, Seychelles, Reunion Island, Madagascar, Kenya, Tanzania, Uganda, Rwanda, Burundi, Ethiopia, Djibouti, Eritrea, Somalia, Sudan, Chad, Mali, Guinea, Sierra Leone, Liberia, Ivory Coast, Burkina Faso, Ghana, Benin, Nigeria, Senegal, Gambia, Guinea-Bissau, Cape Verde, São Tomé and Príncipe, Equatorial Guinea, Sao Tome and Principe, Cabinda, Angola, Namibia and South Africa.
Pacific sleeper sharks, Somniasus pacificus, live in coastal waters of Australia and New Zealand. There are three species recognized: S. pacificus, S. australis, and S. maculatus. They grow up to 2m long.
The females lay clusters of 4–20 eggs per clutch. Each cluster contains one male and several females. Females do not guard their nests; males take over guarding duties once the young have hatched.
Females give birth to litters of 5–10 pups every 3–4 months. Pup size varies depending on temperature, food availability, and maternal care.
In cooler water temperatures, newborn pups are smaller than those reared in warmer conditions.
What does a Pacific sleeper shark look like?
Pacific sleeper sharks are one of the least known species of sharks. They’re rarely seen because they spend much of their lives underwater, hiding away in dark places such as caves and undersea ledges. But when they do surface, it’s usually during mating season.
They’re found worldwide in tropical and subtropical waters, including the western Atlantic Ocean, Gulf of Mexico, Caribbean Sea, Indian Ocean, South China Sea, East China Sea, Japan Sea, Yellow Sea, Bismarck Sea, Mozambique Channel, Australia, New Zealand, Hawaii, California, British Columbia, Canada, and Chile.
Where do Pacific sleeper sharks live?
Pacific sleeper sharks live in… you guessed it… the Pacific Ocean! They’re the Pacific equivalent of the legendary Greenland shark that lives in Atlantic waters. And like the Greenland shark, the Pacific sleeper shark lives deep underwater, usually about a mile beneath the ocean surface. But unlike the Greenland shark, which spends most of its life in the open seas, Pacific sleeper sharks prefer to hide out in the depths of oceans.
People used to think that Pacific sleepers lived north of Alaska. But recent studies show they may actually be found anywhere along the western coast of North America, including Hawaii. Some scientists believe they spend most of their time near the bottom of the world’s oceans, preferring to stay there rather than move around. So while they might seem to be just another “deepwater shark,” they’re really one of the deepest dwellers in our planet’s oceans.
Coping with the Deep, Salty Sea
Sharks don’t just live in shallow coastal waters — they’re found all over the world, including in deep ocean trenches. And like most animals, they have adapted to the challenges of living in different environments.
A recent study published in Scientific Reports explains how one species of fish copes with extreme conditions in the open sea. Researchers discovered that the sharks’ kidneys produce extra amounts of urea, which allows them to tolerate high levels of dissolved salts. This discovery could help scientists better understand why humans develop kidney stones and other diseases linked to too much uric acid in our bodies.
The researchers used CT scans to measure the density of the shark’s bones and compared those measurements to the amount of urea present in the shark’s blood plasma. They found that the highest concentrations of urea occurred in the shark’s liver, where it helped stabilize proteins in the shark’s cells.
But there’s a downside: excess urea makes the shark’s proteins unstable. So the sharks produced even more TMAO, which stabilizes proteins and prevents them from breaking down. This process allowed the sharks to adapt to the high levels of dissolved salts in the water around them.
What do Pacific sleeper sharks eat?
The Pacific sleeper shark is one of the most mysterious creatures in the world. This species lives in the cold waters of the Southern Hemisphere, where it spends its days swimming lazily around looking for food. Its diet consists mostly of small fish, squid, octopus and crustaceans. But what exactly is a sleeper shark doing out here in the middle of nowhere? What makes it different from other sharks? And why does it look so strange?
Pacific sleeper sharks are known for being among the largest members of the family Hemiscylliidae, and they grow to lengths of about 7 feet. They live in tropical oceans throughout the southern hemisphere, including Australia and New Zealand. These sharks spend their days slowly cruising around in the water, occasionally gliding along the seafloor. They are ambush hunters; once they spot something tasty, they swim toward it quickly, open their mouths wide, and swallow whatever they find inside. They don’t bite off chunks of flesh—they just open their mouth wide, pull in their target, and close their jaw. Then they continue eating while floating motionless in the water.
What are the threats to Pacific sleeper shark conservation?
Pacific sleeper sharks are one of the most mysterious creatures in the ocean. They’re often found swimming alone in deep waters, making it difficult to study them. However, researchers think that the species could be threatened by commercial fishing gear like longlines and gillnets. These methods catch everything from whales to large schools of tuna, and sometimes accidentally snag sleeping sharks along with their prey.
The largest known specimen weighed nearly 2,500 pounds and measured over 20 feet across. A single sleeper shark could weigh up to 3 tons, making them some of the heaviest fishes in the world. This makes them incredibly important to marine ecosystems, since they play a key role in maintaining food chains.
But what exactly do they look like? What do they eat? Do they sleep? How big are they? Scientists still don’t know much about these fascinating sharks, despite being able to observe them in their natural habitat for thousands of years.