3. Greenland sharks have been observed at depths of up to 7,200 feet.
Found in the sub-Arctic, Greenland sharks can survive the near-freezing temperatures of these waters thanks to a compound called trimethylamine oxide. This compound acts as a natural antifreeze and prevents ice crystals from forming in the sharks’ bloodstream. This compound also makes Greenland shark meat poisonous to humans and other mammals, so this species has no natural predators. Greenland sharks are among the most massive sharks globally and have been known to grow as long as 21 feet long. Greenland sharks are not spotted frequently because of their ability to dive to such extreme depths. Not only can they dive as deep as 7,200 feet, but they also sometimes can be found relaxing on the slopes and shelves far under the ocean’s surface. Although all sharks are cold-blooded, this particular species truly thrives in a frigid environment. They always migrate to the coldest part of the water each season. In fact, Greenland sharks are the only known shark species that can tolerate Arctic conditions all year long.