How to Identify a Greenland Shark

The Greenland Shark is a sluggish and mysterious deep-sea fish. It only lives in the Arctic seas, and unlike many sharks, it can swim at depths of over 6,000 feet. Surprisingly, for an animal living in such extreme conditions, the Greenland Shark has a long history of contact with humans. The Inuits tell legends of the shark's birth from a woman's old washcloth and Icelanders eat its rotted flesh as a traditional delicacy.

Difficulty: Moderate

Instructions

1. Look at the color of the shark's body. Although color varies from fish to fish, Greenland Sharks are usually a dark shade of greyish brown. They may also have white splotches scattered around their bodies.

2. Observe the size of the shark's head. The Greenland Shark's scientific name is somniosus microcephalus, indicating its sleepy behavior (somniosus) and remarkably small head (microcephalus).

3. Count the number of the shark's dorsal fins. Like the Great White and mako sharks, the Greenland Shark has two dorsal fins: a main fin and a keel fin. The second fin typically stabilizes fast-moving sharks, so it's a strange feature for a fish as sluggish as the Greenland Shark.

4. Approximate the shark's size. Greenland Sharks are among the largest in the world, occasionally reaching sizes of over 20 feet. Only the Basking, Great White and Whale Sharks are larger.

5. See if the shark has a small creature attached to its eye. Greenland Sharks are unique for the bioluminescent parasites, called copepods, that live on their eyes.