7 Cool Facts About the Greenland Shark
This week, video popped up of a researcher freaking out after he spotted a rare Greenland shark on footage he had downloaded from a remote camera in the Russian arctic (you can watch the hilarious video above). Here are a few things you might not have known about this elusive deep sea denizen.
1. The first part of its scientific name, Somniosus microcephalus, roughly translates to “sleep,” because of the shark’s slow swimming; the second part of its name means “small head” (pretty self explanatory). In addition to Greenland shark, it’s sometimes called a sleeper shark or a ground shark, and it goes by a number of other names as well: In Greenland, its names include ekaluggsup piara, ekaluksuak, eqalussuak, and eqalusuak; in the Netherlands, South Africa, and Turkey, it’s called hakaring; in Italy, it's called squalo di groenlandia lemargo; and it’s referred to as tiburon boreal in Spain.
2. It’s one of the largest living sharks. At 6.5 feet long, the one seen above was probably very young; on average, they grow to 14 feet, and can get as large as 21 (or maybe 24) feet. But they grow slowly, at an average rate of a quarter-inch a year. The females are bigger than the males.
3. Greenland sharks might live as long as 200 years!
4. Its meat is toxic—at least if you eat it fresh. Its flesh contains high concentrations of trimethylamine oxide (TMAO), which “helps stabilize [the shark’s] enzymes and structural proteins against the debilitating effects of cold and extreme pressure,” according to the ReefQuest Center for Shark Research. In mammals, though, TMAO gets broken down during digestion and causes a number of horrible symptoms, including “stiff movements, hyper-salivation, vomiting, explosive diarrhea, conjunctivitis, muscular twitching, respiratory distress, convulsions, and—in severe cases—death.” It also makes people appear as though they’re drunk, which is why, according to the Florida Museum of Natural History, natives of Greenland say that people who are drunk are “shark-sick.” The Greenland shark’s flesh is so toxic that it earned a spot in Guinness World Records 2013, but it can be consumed if it’s prepared properly: It either needs to be boiled with several changes of water, or buried for as long as 12 weeks so that it freezes and thaws several times, then hung up to dry for a few months. The resulting snack is called hákarl; according to the Wall Street Journal, chef Anthony Bourdain called it "the single worst, most disgusting and terrible tasting thing" he's ever eaten.
5. The Greenland shark will eat pretty much anything, dead or alive. Though it mostly feeds on other fish—including small sharks, eels, lumpfish, and flounder—some specimens have been found with entire reindeer in their stomachs. One was found containing a juvenile polar bear's jaw, and this shark was found choking on a moose hide.
6. In the deep ocean where the Greenland shark typically lives—it’s been spotted as deep as 7220 feet—it doesn’t need great vision. And that’s a good thing, considering that these sharks are hosts for Ommatokoita elongata, a 2-inch-long parasitic copepod that attaches itself to the shark’s eyes, causing lesions that can lead to blindness. According to Daily Parasite,
The adult female copepod attaches herself to the shark's eye with an anchoring structure call the bulba, and grazes on the surface of the cornea. … There are two possible reasons for the copepod's attachment site. Shark skin is covered in microscopic, teeth-like structures call denticles which can make it difficult for parasites to attach themselves to skin (though some species of parasitic copepods manage). Secondly the eye is considered to be a "immunologically benign environment" for parasites, thus such an attachment is less likely to illicit an immune response.
It sounds gruesome, but the sharks don’t seem to mind; some even have copepods in both eyes.
7. It has crazy teeth. On the top jaw, they’re thin and pointed, without serration. The teeth on the lower jaw are broad, square, and interlocking with short, smooth, outward-pointing cusps. The top teeth serve as anchors while the bottom teeth do the cutting.