Part of the reason this shark is so difficult to study is because of the extreme depths at which it lives. Greenland sharks have been recorded at depths of more than 7000 feet, and usually only come to the surface near ice floes in the winter.
Greenland sharks are thought to be ambush predators, pinning and consuming a large variety of bottom-dwelling fish and crustaceans. They are also known to be scavengers, and like many sharks will eat just about anything, living or not, that they can find. Despite their size, Greenland sharks are notoriously sluggish by nature and are not considered dangerous to humans.
The exact lifespan of the Greenland shark is uncertain. However, scientists have determined that they grow at an extremely slow rate of less than one centimeter per year. If this is the case, fully grown adults specimens may be well over 200 years old, making this shark the longest-lived vertebrate on the planet.