Claire Corlett

Fish Food, Fish Tanks, and More
Animated Shark Facts – Sleeper Sharks

Animated Shark Facts – Sleeper Sharks


Sharks. They are one of the most mysterious kinds of animals. Hardly any other creatures in our oceans are as fascinating to us as as they are. However, despite sharks being one of the most diverse animals on the planet, with more than 400 different species, only a handful of them seem to be appreciated, or even noticed by the broader public. So, today, I want to talk about one of the lesser known groups of sharks. Sleeper sharks. More specifically, about the Greenland Shark, found in the North Atlantic and Arctic ocean, and the Pacific Sleeper Shark, found in the North Pacific. These two species are morphologically so similar that some scientists still take into consideration the possibility that they are all the same species. The only major difference between the two is their distinctive ranges. So what makes these sharks so special? First of all, they are one of the largest living species of sharks, with an average size of just under 4 meters, or 30 feet, and a speculated maximum size of 6-7 meters, or 23 feet, based on video evidence, they are comparable to the Great White Shark in size. That not many people have heard of them, despite their huge size, is mainly due to the fact that very little is known about them, and they are very rarely observed, which in turn is due to their unique lifestyle While most sharks live somewhat close to the surface, Sleeper sharks instead spend most of their lives in the deep cold waters, near continental shelves and slopes. They are in fact one of the deepest diving fish. Rare sightings by cameras of underwater robots or oil rigs document this astonishing ability. Greenland Sharks have been found at depths of up to 2600 meters, or 8500 feet. Only the Portuguese Dogfish, a different species of Sleeper Shark, and the deepest living shark known, has been found deeper than that, at a depth of 3600 meters, or 12000 feet. Adapted to living in frigid waters between minus 2 to 10 degrees celsius, you can only find them close to the surface in places where shallow water is cold enough for them, primarily, in the Arctic. This makes them not only the biggest fish you can find there, but also the only shark that can tolerate Arctic temperatures year round. As a result, they were long thought of as purely polar animals, but the continuous sightings of individuals in further south regions suggests that they are a lot more common than previously thought. To find out more about these understudied animals, researches examine the contents of the stomachs of sharks accidentally caught by commercial fishermen. Originally, it was suspected that these sharks were scavengers that feed primarily off carrion. But these new studies confirm their much broader food spectrum. It seems Sleeper Sharks are opportunistic apex predators that will eat just about anything that comes across their path. Nearly every animal that shares a habitat with these sharks could be found in their stomachs. Most of it is fairly unspectacular, like a variety of small and medium sized fish crustaceans, octopuses, jellyfish, and gastropods. However, other findings baffle the researchers. Many Greenland Sharks have been found with seemingly fresh meat of seals inside their stomachs, suggesting that they’re actively hunting. Other notable finds include the remains of small whales, other sharks, dogs, horses, reindeer, and moose A similar study done for pacific sleeper sharks revealed countless squid beaks of colossal and giant squids in their stomachs which suggests that they must be a big part of their regular diet. This makes sleeper sharks only the second animal known to science that hunts these squids for food besides the sperm whale. Some researchers also suspect that greenland sharks are responsible for a series of yearly seal killings of the coast of Nova scotia. This strange phenomenon became commonplace in recent years. as every year, hundreds of mutilated seals are washed up on the shore of Sable Island. The wounds these bodies bear are extremely unusual. Most of them are long, clean edge corkscrew-like wounds that appear to have been made with a sharp instrument. But whether or not the Greenland shark is actually the corkscrew killer of Sable Island is still, to this day, not solved. Other potential suspects are killer whales, and boat propellers. How sleeper sharks could ever catch living prey, is also still a mystery. For one thing, they are absurdly slow – as the name might suggest. A satellite tagging study found that Greenland sharks are only cruising at a mere 1.1 kilometres per hour through the ocean – roughly at the speed of a crawling baby. This makes them slower than any other shark. Pacific sleeper sharks aren’t much faster either. And although both species are capable of quick bursts of speed in order to hunt even then, they are far to slow to catch a swimming seal or many of the other things they might want to eat. This lead scientists to believe that these sharks are primarily ambush predators. that use the darkness of the deep sea and the ability to glide silently through the ocean to sneak up on their prey It is also suspected that they hunt seals while they’re sleeping, or carelessly poking their heads through ice holes to breathe. Still with Still, with nobody directly observing them actively catching prey The question, how they hunt, remains mostly unresolved Also, because many sleeper sharks appear to be almost blind. The huge majority both pacific sleeper sharks and Greenland Sharks are colonized by a parasitic copepod that attached itself to the front of the shark’s eyes and eats its cornea tissue. It was hypothesised that the parasite might be bioluminescent, attracting prey for the shark and making it a mutualism rather than parasitism. However, there was never any scientific evidence for this theory and it has been debunked multiple times by now. Overall, this parasites don’t appear to affect this sharks too severely. Adapted to life in the deep sea, ice site isn’t mandatory for their survival. instead, they lackly rely on their other senses particularly on their sense of smell which is highly developed. Another topic we know very little about is their reproduction. As neither mating, no birth has been ever observed so far. However, we do know that Greenland Sharks are ovoviviparous. Like the Great White and many other sharks. This means, that they don’t lay eggs but instead give births to life young after the eggs have hatched inside the universe. Additionally, new research from the University of Copenhagen revealed that they only reach sexual maturity at about age of 150. This has likely to do with their very slow metabolism. And the cold waters that they inhabit. Which results in this sharks having a very slow growth rate of only between 0.5 to 1 cm per year. This was calculated through radiocarbon dating of certain metabolicly inert proteins from the shark’s eye lenses. These proteins are not renewed after being synthesised in the body when the shark was apart. Which allowed the researchers to estimate when the 28 individual examine were born. Using this technique, they established that the largest shark, a 5 meter long female was between 270 and 512 years old. Where the actual value most likely being somewhere in the middle. This means that the Greenland Shark has the longest known lifespan of all vertebrate species. Unfortunately, the long enter wall between birth and sexual maturity might make them vulnerable to over fishing and environmental change. To what extend they endangered and how the warming of the ocean is impacting these sharks is however not known As no accurate global population numbers are available. Luckily, today there isn’t any large-scaled commercial fishery for them anymore. However, in the first half of the twentieth century, Greenland shark was commercially fished for its liver. This were used for lamp and machine oil and because of it, the sharks were killed in great numbers before

100 comments on “Animated Shark Facts – Sleeper Sharks

  1. Sorry for not uploading last week, but I decided to skip that week to be able to make this video twice as long. I really couldn't fit the topic in a 4-5 min video, at least not the way I wanted it to do.
    For those of you who don't know, this is actually a reworked video – I covered Sleeper Sharks in an early video but deleted it maybe a month ago with the intention to rework it.
    But because the original was one of my first successful videos and a lot of people(that are now my subs) liked it, I felt I really had to deliver. Hope I did ; )

    With the rework now finally out of the way the next videos will be normal-length videos again – so expect a new one during the next week. After all the plan was to upload more and not less …

  2. Sleeper shark: I'm with kayla and she's is an amazing shark

    Sharks bro: wait you know she's only 145 years old right

  3. When I read "sleeper sharks" I imagined fish that weren't sharks and then you say a code word and it triggers their brains into becoming a shark.

  4. Could you imagine living over 300 years just to die getting tangled in a net? That's almost insulting

  5. Can you imagine, living peacefully for over 300 years, just to have a cunt pick them up and kill them for nothing?

  6. I didn't know Greenland Sharks could live in freshwater, even briefly, I learned something new today lol

  7. I like hearing information from people with your accent. It's like a buff guy, but one sitting in a blanket sipping on hot chocolate in Winter.

  8. Some traditions should die, like eating rotting poisonous sharks that need at least 150 to reproduce and plenty more.

  9. Could be the case that sleeper sharks feed mainly on carrion which has been preserved by the icy waters of their habitats. Who knows, maybe some of the bodies from the Titanic Disaster may have been sleeper food.

  10. While they may not seem as exciting or intimidating as the more well known sharks, I've always been incredibly fascinated by sleeper sharks

  11. Forst of all there was a plasiosaur at the end and second of all these videos of marine animals are very interesting and almost relaxing plus how you where talking about the parasite on the eye of the sleeper shark a had a few manly tears coming

  12. Didn’t know Greenland sharks can be found off the coast of Florida and that Pacific one can be found in California that’s nuts

  13. it has been confirmed that greenland sharks are the ones behind the corkscrew wounds at sable island.
    The shark most likely sneaks up to the seal while they are sleeping, pin them down with their upper jaw, and rotate it's body to saw with it's lower jaw. (it's upper jaw has barbs used for pinning, and the lower jaw is like a saw)

  14. You know. Cause breathing is careless. These seals get no break.

    Thanks for the video. It was very informative. I knew about them, but, the contents of their stomach took me by surprise. These are the sloths of the sea. I love it!

  15. Anyone else just get a 20 minute ad? I love this channel and all, but I am not sitting through an ad that's longer than the video itself.

  16. Sleeper sharks would benefit the most from there electro receptors rather than eyesight anyway i'd assume which is perhaps why they are not impeded by the eye parasites? i may be wrong but i think most scientists believe sharks hunt more using them anyway? not that that would help with their lack of speed lol, but i think i've seen a show that has show them are somewhat scavengers?

  17. Wait but of sleeper sharks live in the deep sea you coudnt take it outside of the water because it woud explode from internal pressure

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