Happy Holidays! Meet the deep-sea shark who can survive in the frigid waters of the Arctic Ocean.
Key Features & Appearance
As one of the largest cartilaginous fish, Greenland sharks have disproportionately tiny snouts and fins. In fact, they can reach up to 23 feet in length and 1.5 tons in weight. One of their most distinctive features are their teeth, with their top teeth being pointed and narrow, while their lower are broad and flat. With different types of teeth at their disposal, these sharks can use their top teeth to grip their prey, while their bottom cuts into the flesh.
Compared to other shark species, Greenland sharks have relatively poor vision. Crustacean parasites, known as Ommatokoita elongata, are known to attach to one of the shark’s eyes and damage the cornea. Luckily, Greenland sharks can utilize their other senses to survive in the deep waters of the Arctic.
Habitat & Distribution
Though their name suggests otherwise, Greenland sharks are found far beyond Greenland, living throughout the Arctic and North Atlantic Oceans. They are not commonly observed at the surface, but have been recorded at depths of up to 7,200 feet.
Greenland sharks are experts at surviving in exceptionally cold temperatures. Average temperatures can range from 28.4 to 44.6 degrees Fahrenheit, making Greenland sharks the only shark species to survive consistently in such extreme temperatures. The key to their success lies in their body tissues, which contain high levels of chemical compounds that help to prevent ice from forming internally.
Diet
Unlike many other species of sharks, Greenland sharks rely on scavenging. Their favorite foods include carrion, fish, crustaceans, and squid. Along with scavenging, they opportunistically hunt seals and are known to be extremely stealthy predators.
However, these sharks have been discovered with land animals in their stomachs, such as seabirds, reindeer, horses, moose, and even polar bears! In the presence of a Greenland shark, it’s likely best not to stray too close to the ocean’s edge.
Reproduction
Surprisingly, Greenland sharks don’t reach reproductive age until 150 years old! With lifespans of at least 272 years, these sharks mature relatively late and have a low reproductive rate—making it essential that Greenland sharks can reach reproductive age.
These oviparous sharks produce roughly 10 offspring at once; little else is known about their reproductive behaviors. However, many scientists believe that these sharks are independent from the moment they are born (like many other shark species).
Threats
Though humans rarely directly encounter Greenland sharks, they pose a threat to the species nonetheless. Like numerous other shark species, Greenland sharks are threatened by overfishing, pollution, and melting Arctic ice. Additionally, these sharks were hunted for centuries, primarily for their liver oil.
Status
According to the International Union for Conservation of Nature (IUCN), Greenland sharks are listed as “Vulnerable.” Their populations are steadily decreasing, particularly because of their slow-growth and late reproduction age.
Fun Fact
Did you know that Greenland sharks are one of the slowest-swimming shark species? Their scientific name Somniosus microcephalus even translates to “sleepy small-head.” On average, they swim less than roughly 1.9 miles per hour. Their slow pace makes their hunting abilities even more impressive!
Works Cited
“Greenland Shark, Facts and Photos.” Animals, www.nationalgeographic.com/animals/fish/facts/greenland-shark.
“Greenland Shark.” Encyclopædia Britannica, Encyclopædia Britannica, inc., www.britannica.com/animal/Greenland-shark. Accessed 17 Dec. 2023.
“Greenland Shark.” Save Our Seas Foundation, saveourseas.com/worldofsharks/species/greenland-shark.
Nicholas Dulvy (Simon Fraser University, Canada / IUCN SSC Shark Specialist Group), et al. “The IUCN Red List of Threatened Species.” IUCN Red List of Threatened Species, 20 June 2019, www.iucnredlist.org/species/60213/124452872.
“Somniosus Microcephalus.” Discover Fishes, www.floridamuseum.ufl.edu/discover-fish/species-profiles/somniosus-microcephalus/.
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