Blind, slow and 500 years old – or are they? How scientists are unravelling the secrets of Greenland sharks

Described by one researcher as looking already dead', the enigmatic creatures are one of the least understood species on the planet

It looks more like a worn sock than a fearsome predator. It moves slower than an escalator. By most accounts, it is a clumsy and near-sightless relic drifting in the twilight waters of the Arctic, lazily searching for food scraps.

The Greenland shark, an animal one researcher (lovingly) said, looks like it's already dead", is also one of the least understood, biologically enigmatic species on the planet.