Greenland Shark (Somniosus microcephalus) Copyright Richard Ellis 1997 Somniosus microcephalus -- known as the the sleeper shark, Greenland shark, or gurry shark -- lives in polar waters all year round. It is a large shark: lengths of 8 to 14 feet are not unusual, and the largest measured specimen was 21 feet long. (Only the whale shark, basking shark, and great white shark are known to reach ...