The Greenland shark, scientifically known as Somniosus microcephalus, resides in the frigid depths of the Arctic and North Atlantic oceans. As one of the largest species of shark, reaching lengths over 20 feet, its size rivals that of the great white shark. This animal also holds the record as the longest-living vertebrate on Earth, with lifespans estimated to be several centuries long.
The Reality of Greenland Shark Behavior
The Greenland shark is not considered aggressive toward humans due to its unique physiological adaptation to its extremely cold environment. These sharks inhabit waters that hover near the freezing point, typically between 1 and 12 degrees Celsius. Life in such cold conditions necessitates a slow metabolism to conserve energy, which directly impacts the animal’s behavior.
This slow metabolic rate results in a lethargic and sluggish demeanor, earning them the classification of a “sleeper shark.” While they appear large and formidable, their movements are generally slow and deliberate. Their body chemistry is optimized for a slow life, leading to a temperament that is overwhelmingly passive rather than confrontational.
Slow Speed and Ambush Hunting Strategy
The Greenland shark’s slow movement, with typical cruising speeds measured at less than two miles per hour, raises the question of how it can secure enough food to survive. Instead of relying on bursts of speed, this predator employs a highly effective strategy of stealth, ambush, and opportunism.
The shark’s diet includes a wide variety of fish, such as skates and eels, but it is also known to consume marine mammals like seals. Researchers hypothesize that the shark ambushes seals while they are resting or sleeping in the water, a theory supported by the shark’s inability to outrun a healthy, awake seal. Furthermore, the Greenland shark is a significant scavenger, readily consuming carrion, which can include the remains of terrestrial animals like reindeer or even polar bears that have fallen into the water.
Why Human Encounters Are Extremely Rare
The minimal danger the Greenland shark poses to humans is primarily a result of geographical and spatial separation. This species prefers a deep-water existence, typically dwelling at depths greater than 600 feet. While they occasionally venture to the surface, their primary habitat is far removed from areas of human recreational activity.
The shark’s range is confined to the Arctic and North Atlantic, regions too cold for sustained human swimming or diving without specialized equipment. There are no confirmed records of a predatory attack on a human by a Greenland shark. Historical accounts of human remains found in a shark’s stomach are anecdotal and widely attributed to scavenging, meaning the shark consumed a body that was already deceased. Encounters are almost exclusively limited to accidental captures as bycatch by deep-sea commercial fishing vessels.