Although Greenland sharks are not typically aggressive, they are most definitely some of the largest sharks on the planet. While quite a bit of mystery remains regarding this enormous and elusive fish, we have still been able to learn some interesting facts.
To give you an idea of just how large they are, Greenland sharks usually grow up to 21 feet (6.5 meters), and they weigh approximately 2,000 lbs (900 kilos)! These usually sluggish sharks have very unique physical characteristics including their varying coloration, interesting fins, and dissimilar teeth.
An adult can be one or more of a few different colors. These sharks can be slate gray, purplish gray, violet, brown, or black. In addition, the sides of Greenland sharks usually have a purple tint, white spots, or dark bands. In other words these sharks can be great inspiration for designers and artists!
Despite the massive sizes of these sharks, they ironically have small fins. Their little dorsal fins are equal in size, situated in the middle of the shark’s trunk, and are completely spineless. The Greenland shark’s caudal fin is asymmetrical, and although they do not own anal fins, their short, wide tails aid in short acceleration bursts.
Another exceedingly interesting physical attribute unique to these sharks is their eyes. The eyes are very small, and they contain Spiracles behind and above them. Unexpectedly, the majority of these sharks are blind due to the fact that they have parasites hanging from their eyes. These pinkish-white parasites are called copepods, and they attach themselves to the Greenland sharks’ cornea.
Earlier I said their teeth are dissimilar; this is because their top teeth are completely different than their bottom teeth. The teeth on the top jaw are slender, pointy, and not very large. On the contrary, the bottom row of teeth are substantially larger, broader, and smoother than those on the top row.
Diet and Hunting Behavior
Since they hunt underneath the ice in freezing cold waters, their food searches are conducted in almost complete darkness. Due to their lack of sight caused by copepod parasites, this darkness factor doesn’t make much of a difference for these sharks.
Sense of Smell
Greenland sharks have an impeccable sense of smell. Therefore, they typically have no problems finding food. They slowly wander the cold ocean looking for any scent of a dead animal or carcass.
Preferred Food Source
These sharks particularly prefer the tastes of Narwhal and Beluga whale carcasses, and they sometimes participate in cannibalism. Furthermore, these sharks also enjoy seals, cetaceans, sea lions, salmon, lumpfish, halibut, char, capelin, herring, and other fish.
Although they feed on an extensive amount of various animals, their skin is poisonous to most other animals. For example, Inuit hunters feed on these whales, however they do not feed raw shark meat to their dogs because it causes them to behave drunkenly.
Copepod Parasites as a Hunting Aid
Many have an interesting and plausible theory concerning the connection between Greenland sharks and copepods. It is believed that these parasites somehow lure food to the sharks; once the prey is within 3 feet (1 meter) away, the shark is then able to suck the food into its mouth by inhaling. If this is indeed true, it would make perfect sense as to why the copepods are tolerated, considering that they cause blindness to the sharks. So while it’s believed these sharks mostly eat carcasses of animals who have already died, this could possibly be a way to obtain a food source when living creatures are the only treats around.
Greenland sharks inhabit freezing waters with temperatures between -2 and 7 degrees Celsius. Interestingly enough, Greenland sharks are the only species that consistently live in these arctic and sub-arctic temperature waters. During the summer months, Greenland sharks spend the majority of their time in extremely deep waters of the ocean; they can be found anywhere from 600 to 2,400 feet (180 to 730 meters) in the depths of the ocean. Contrarily, during the winter months, these sharks enjoy swimming near the water’s surface, and can often be found near the edge of ice flows.
If you would like to see one of these enormous animals for yourself, they can be found in the North Atlantic Ocean from Baffin Island, to the Gulf of St. Lawrence; they can also be found as far south as the Gulf of Maine, and sometimes even in the Gulf of Mexico. Greenland sharks have also been spotted near the mouths of rivers, such as the Saguenay River in Quebec.
Reproduction and Offspring
There isn’t a lot of known information regarding the reproduction process of these sharks, however, we do know that they are Viviparous. At the appropriate time, the mother gives birth to her pups. Greenland sharks can have up to 10 pups in a litter.
Fortunately, this particular species of sharks are no longer commercially harvested. In the past, these sharks were commonly hunted for their livers in Greenland, Norway, and Iceland, however this is not nearly as customary today. Inuit hunters do eat these sharks, but their meat is not a widespread delicacy for a few reasons: they are almost always in freezing waters, and their meat has to be prepared a certain way due to the fact that it is poisonous when fresh. When the sharks travel to rivers such as those in Canada, Canadian fishermen who are harvesting halibut, or other types of fish sometimes catch them. However, we can be grateful for the fact that humans have not caused the population of Greenland sharks to almost completely deplete, which is the case for so many other shark species.