Giant Cookiecutter Shark is an unknown fish of Arctic waters off Alaska. Takes large circular bites out of whales and dolphins.
While working in Alaska, a colleague of Eugenie Clark reported that a dead Narwhal (Monodon monoceros) was pulled up alongside their research boat for examination one night. In the morning, as the scientists began to examine it, they found round bites on the animal that strongly resembled those left by the Cookiecutter sharks (Isistiusspp.). However, they were much bigger than bites made by known cookiecutters.
- The Cookiecutter shark (Isistius brasiliensis) and the Largetooth cookiecutter shark (I. plutodus) are both subtropical species. Neither grows much longer than 18–20 inches. The cookiecutter clamps onto the flesh of its much larger prey with its jaws and bites down with the sharp teeth on its lower jaw to extract circular chunks of flesh. Tunas, elephant seals,dolphins,whales,swordfish, and other large marine animals have been found with large gouges that were probably inflicted by this shark. A giant species of cookiecutter would theoretically take much larger bites.
- The Pacific sleeper shark (Somniosus pacificus) frequently scavenges whale carcasses.
- The Greenland shark (Somniosus microcephalus) also leaves razor-edged, circular bites on narwhals and seals.