( Image credit: Doug Perrine/Alamy Stock Photo)
Greenland sharks ( Somniosus microcephalus) come from a household of sharks called sleeper sharks, which move gradually and stealthily through the water. They are the longest-living vertebrates, or animals with foundations, enduring for approximately centuries in the deep, cold waters of the Arctic and North Atlantic oceans.
These sharks slip up on live victim and scavenge dead animals, consisting of other sharks, seals, drowned horses and polar bears. Researchers are finding out more and more about these strange sharks that hardly ever experience human beings, however there are still numerous unknowns surrounding their way of lives.
How huge are Greenland sharks?
Greenland sharks are amongst the most significant sharks on the planet; they mature to 24 feet (7.3 meters) long and weigh approximately 2,645 pounds (1,200 kgs), according to the St. Lawrence Shark Observatory (ORS). That’s longer than terrific white sharks ( Carcharodon carcharias), which are approximated to mature to 20 feet (6 m) long, with unofficial reports recommending they can reach 23 feet (7 m) in length, according to the Florida Museum of Natural History.
Size: Up to 24 feet (7.3 m)
Life period: 272 years (price quote)
Conservation status: Vulnerable
Greenland sharks have round bodies that can be black, brown, gray or a mix of all 3 colors, and they might have areas. These sharks likewise have teeth-like scales, called dermal denticles, covering the surface areas of their bodies. The scales minimize drag and assist the sharks move more calmly through the water, according to the ORS. A Greenland shark’s mouth includes 48 to 52 teeth in its upper jaw and 50 to 52 teeth in its lower jaw. The upper teeth are pointed, to assist the sharks hang on to bigger food, while the lower teeth are large and curved sideways so the sharks can take round pieces of flesh from victim by moving their head in a circular movement, according to the ORS.
Ocean parasites called Ommatokoita elongata are frequently connected to the eyes of Greenland sharks. The parasite tends to reside in simply among the shark’s eyes, however this can still render the shark partly blind. Due to the fact that the sharks rely more on their other senses to capture victim in the dark ocean waters, the parasites do not appear to impact the sharks much, according to the Florida Museum of Natural History.
Related: Ancient Greenland shark exposes its age in spooky undersea video
How long do Greenland sharks live?
Greenland sharks’ precise life expectancy is unidentified, however they are thought about the longest-living sharks, and the longest-living vertebrates, on the planet. A 2016 research study of the sharks’ eye tissue released in the journal Science approximated that Greenland sharks have an optimal life expectancy of a minimum of 272 years. Scientist approximated that the earliest Greenland shark because research study had to do with 392 years of ages, however the price quote had a big margin of mistake of 120 years, which caused speculation that Greenland sharks might live to 512 years of ages. The approximated variety hasn’t been validated.
” It’s crucial to remember there’s some unpredictability with this quote,” Julius Nielsen, co-author of the 2016 paper, formerly informed Live Science. “But even the most affordable part of the age variety– a minimum of 272 years– still makes Greenland sharks the longest-living vertebrate understood to science.”
Greenland sharks reside in the sluggish lane, with a leading swimming speed of less than 1.8 miles per hour (2.9 km/h). They likewise grow gradually at less than 0.4 inch (1 centimeter) each year and have sluggish metabolic process, according to the National Oceanic and Atmospheric Administration (NOAA). Researchers do not yet understand how Greenland sharks live so long however it might be connected to their sluggish way of living.
Related: No, researchers have not discovered a 512- year-old Greenland shark
Where do Greenland sharks live?
Greenland sharks reside in the Arctic and North Atlantic oceans from North America to Greenland and from Portugal to the East Siberian Sea, according to the International Union for Conservation of Nature (IUCN). The sharks have a big variety and can be discovered swimming from the surface area to depths of 8,684 feet (2,647 m), the IUCN states.
Scientists still have much to discover how Greenland sharks live and recreate. Female Greenland sharks bring to life live young, called puppies, that hatch from soft eggs that the women bring inside their bodies. In a 2020 research study released in the journal PLOS One, scientists approximated that Greenland sharks bring to life in between 200 and 324 puppies per pregnancy, depending upon the size of the shark. Greenland shark puppies are simply 14 to 18 inches (35 to 45 centimeters) long when they’re born.
What do Greenland sharks consume?
Greenland sharks have a diverse diet plan that consists of fish, other sharks, eels and marine mammals, such as seals. They have actually likewise been discovered with drowned land animals, consisting of horses and reindeer, in their stomachs, and have actually been seen in great deals at the sea surface area, feeding together on the remains of whales and fish eliminated throughout industrial whaling and fishing, according to the University of Michigan’s Animal Diversity Web (ADW).
Greenland shark taxonomy
Genus and types: Somniosus microcephalus
Scientists discovered a Greenland shark with the jaw of a young polar bear ( Ursus maritimus) in its stomach, Reuters reported in2008 The scientists were uncertain how it arrived; however most shark specialists thought that the polar bear was most likely currently dead when the shark consumed it, as live polar bears are too unsafe for the sharks to handle. Scientists likewise discovered some polar bear muscle tissue and skin in the stomach of another Greenland shark throughout a 2014 research study released in the journal Polar Biology, and they concluded that the bear was most likely scavenged instead of hunted.
Greenland sharks are near the top of the food cycle, however sperm whales ( Physeter macrocephalus) might hunt them. Chris Harvey-Clark, co-founder of the Greenland Shark and Elasmobranch Education and Research Group (GEERG, now the ORS), composed in Capeia, an online science interaction publication, about tape-recording a Greenland shark apparently running away from the echolocation clicks of a foraging sperm whale. Upon its death, that sperm whale was discovered with its teeth used down to stumps, comparable to those of whale ( Orcinus whale) that eat Pacific sleeper sharks ( Somniosus pacificus), which are carefully associated to Greenland sharks and have likewise hard skin. Harvey-Clark thought that the sperm whale hunted Greenland sharks. Researchers are yet to observe sperm whales searching these sharks in other places.
Related: Sperm whales outsmarted 19 th-century whalers by sharing incredibly elusive strategies
Are Greenland sharks harmful?
There are no validated reports of a Greenland shark assaulting a human. Some anecdotal proof recommends that such attacks might take place. GEERG scuba divers observed a Greenland shark “stalk” a group of scuba divers. They have actually likewise seen Greenland sharks examine scuba diver activities as if they were searching seal victim, according to the ORS. A Greenland shark was supposedly discovered with a human leg in its stomach off Canada’s Baffin Island around 1859, however this report was not confirmed.
Untreated Greenland shark meat is poisonous to human beings, as it consists of high levels of trimethylamine oxide (TMAO), which breaks down into the harmful trimethylamine (TMA) substance throughout food digestion, according to a 1991 research study released in the journal Toxicon. TMA can trigger extreme intestinal tract issues and produces comparable results to extreme alcohol intake. Greenland shark meat is edible just when dried. The dried meat is fed to sled canines in northern areas such as Greenland, according to the Florida Museum of Natural History. The shark is likewise fermented and taken in as a special in Iceland.
Are Greenland sharks threatened?
The IUCN thinks about Greenland sharks to be susceptible to termination. Human beings eliminated Greenland sharks for their liver oil to utilize in lights and other items in between the 13 th and 20 th centuries. The industrial fishing of Greenland sharks for their oil ended by the 1960 s, which assisted their population. Greenland sharks continue to be captured and eliminated as bycatch, or animals that get pulled up by fishers together with their desired catch, for example, in big internet dragged along the bottom of the ocean planned to capture a big number of fish. The majority of the Greenland sharks consumed by people and fed to canines originated from bycatch, although some sharks are targetted on a little scale.
The Northwest Atlantic Fisheries Organization (NAFO), an intergovernmental fishing science and management body, restricts the direct fishing of Greenland sharks and looks for to lower bycatch. The NAFO uses to a lot of fisheries in the Northwest Atlantic ocean and consists of nations such as the U.S. and Canada. The IUCN advises even more defenses, such as bycatch policy, be established for Greenland sharks and imposed.
The IUCN approximates that the Greenland shark population has actually decreased by 30%to 49%over the past 450 years, or 3 shark generations. This decrease was approximated based on a conservative Greenland shark life period of 150 years; the decrease might be much greater if the sharks have longer life periods, as it would take them longer to reach reproductive age and produce more sharks. The international Greenland shark population size is unidentified. Environment modification is likewise injuring the types– for instance, by decreasing Arctic sea ice, which offers fishing fleets simpler access to Greenland shark environment.
- See pictures and videos of a Greenland shark and other deep sea animals come across throughout the NOAA Northeast U.S. Canyons Expedition in 2013.
- Watch this brief video on YouTube about how Greenland shark meat is ready and consumed in Iceland, from Food Insider.
- Learn more about where Greenland sharks cope with an interactive map, from the Encyclopedia of Life.
Patrick is a personnel author for Live Science. His background remains in wildlife preservation and he has actually dealt with threatened types all over the world. Patrick holds a master’s degree in global journalism from Cardiff University in the U.K. and is presently ending up a 2nd master’s degree in biodiversity, advancement and preservation in action at Middlesex University London.