10 Facts About Greenland Sharks

Scymnus glacialis, Squalus borealis or simply just Greenland shark – this iconic species is known by different names and is an elusive creature of the deep ocean. Greenland sharks are masters of longevity, with a life expectancy of nearly half a century! Don’t be misled by its name, this shark does not only live around Greenland. It’s even been spotted even in Caribbean waters. Read on and go on a deep dive into the Greenland shark’s habitat, behavior and lifestyle. But be prepared to take it slow – they are sluggish creatures and even the scientific name of the Greenland shark Somniosus microcephalus roughly translates to sleepy small-head.

1. Greenland Sharks are Big Fellows

The Greenland shark (Somniosus microcephalus) can reach up to 7m (923ft) in length. It can weigh up to 1.2 tons. They are often compared to great white sharks because of their size. Greenland sharks live in the cold water of the North Atlantic, but have been seen in other parts of the world. Females tend to be larger than males. While their sheer size may make for terrifying encounters with humans, this shark is not known to attack people.

2. Greenland Shark Meat is Poisonous

Even if you are a seafood connoisseur, we do recommend caution with Greenland sharks. The toxins (trimethylamine oxide) in the flesh can knock out humans and sled dogs. After accidental consumption, you may feel nausea, dizziness and experience diarrhea and vomiting. And there is even a special term for such a condition: being shark drunk. In the past, natives who ate Greenland shark meat that was not properly treated would experience intoxication similar to heavy drug use.

If you want to taste this toxic delicacy, it has to be prepared correctly. When properly fermented for up to five months (which reduces the toxins), you can enjoy it under the name hakarl (very popular in Iceland).

3. Not a Danger to Humans, but Endangered by Humans

There isn’t any recorded attack of a Greenland shark on a person. While they could certainly harm or even kill humans if threatened, they are not known to be confrontational. However, eating them may harm you. Greenland shark flesh is poisonous and needs to be cooked or fermented (like the Icelandic fermented snack known as hakarl).

Humans, however, are a greater danger to Greenland sharks. Up until the 1960s, fisheries targeted these sharks for their liver oil. Though commercial fishing has stopped, Greenland sharks are occasionally caught accidentally while being entangled in fishing gear.

4. Clandestine and Camera-shy

The odds of seeing these sharks on your Greenland cruise are rather low. The first photograph of a shark was only taken in 1995 and the first ever video of Greenland sharks in their natural habitat was recorded 18 years later. For fans of fish biology: The Natural History Museum in London was able to secure a complete shark specimen for their research in 2014.

5. Greenland Sharks Are Master Divers

Don’t be disappointed if you can’t get a picture of the elusive Greenland shark. They usually dwell in depths of up to 2km (1.2 miles) in the ocean, surfacing very rarely. This is also why it’s also difficult for scientists to study this species.

6. Greenland Sharks Aren’t Picky Eaters

Fish, invertebrates, meat of polar bears, carrion, seals and other prey – Greenland sharks are scavenging the cold waters for whatever they can find. Scientists studying their feeding ecology found that Greenland sharks are also capable of seal hunting by peeling their skin off (like you’d peel an orange). This peculiar technique got them the terrifying nickname corkscrew killer.

When feeding on marine mammals the sharks use their upper teeth as an anchor, and lower jaw to cut their prey into pieces. The lower teeth feature smooth cusps that point outward.

7. Greenland Sharks do not Rush

Why be in a hurry when you can take things slowly? Greenland sharks (also called sleeper sharks or gurry sharks) take it easy. Since they aren’t picky eaters, they are able to take their time and only increase their pace if absolutely necessary. The sleeper shark cruises at a top speed of only up to 2.6km/h (1.6mph).

8. Some Like it Cold…

…such as the Greenland shark. The colder the water, the happier the shark! While all shark species are cold-blooded, this shark migrates to very cold waters ranging from 10C to minus 1C (50-30F). It’s the only shark that can tolerate the frigid Greenland waters year-round. They rarely come to the sea surface and prefer to thrive sluggishly in the cold depths of the oceans.

9. Greenland Sharks Live Slow but Long

The Greenland shark is the world’s longest living vertebrate, reaching a life expectancy of up to 400 years and possibly even more. A slow metabolism and slow growth-rate may be the key to its longevity. Greenland sharks mate late. You may consider yourself a late bloomer, but no other species takes its time like the Greenland shark: they reach their sexual maturity at around 150 years of age.

To study their age, scientists look at the shark’s eye lens tissue, which builds up layers throughout its lifetime, similar to the rings of a tree. Analyzing these layers and using carbon dating give scientists a clue about the shark’s age. So far, the oldest caught shark is estimated to have reached 392 years of age.

10. Greenland Sharks are Practically Blind

Greenland sharks are almost blind. Its poor vision is caused by the Ommatokoita elongata parasite, which is a small crustacean that damages the cornea by latching onto the shark’s eyes. This causes small infections, promoting the growth of scar tissue over time and blinding the sharks. But what Greenland sharks lack in vision, they make up for with their incredible sense of smell. In their deep, dark, cold water habitats, they are perfectly adapted to navigate and can even sense movement of other species around them.

FAQs

Why do Greenland sharks live so long?

Scientists attribute their very slow metabolism to their longevity. A slow metabolism helps Greenland sharks with adapting to the cold, deep waters they inhabit in the ocean.

Are Greenland sharks aggressive?

Though predatory and large, this shark species is not particularly aggressive and usually moves slowly in the cold waters of the North Atlantic Ocean.

Why are Greenland sharks rare?

Greenland sharks are rarely spotted, as they usually spend their time at extreme depths of 2km (1.2 miles).

Is a Greenland shark bigger than a great white?

Greenland sharks (belonging to the dogfish sharks), at up to 7m (23ft) in length, are the largest sharks, featuring a rounded snout, small gill openings and very small dorsal and pectoral fins. Great whites (which are up to 6m/20ft long) are shorter, but heavier. They can weigh up to 2.5 tons, while Greenland sharks only weigh up to 1.5 tons.

Why are Greenland sharks called pee sharks?

Some refer to them as pee sharks as they have high concentrations of urea in their bodies. Urea is just a by-product of the urine filtering process and not actual urine. All ocean sharks retain urea in their bodies, so their salt concentrations equal the ones of the saltwater around them. This helps to maintain the osmotic balance and prevents dehydration.