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

The scientific community has two long held key beliefs about Greenland sharks – they are the oldest living vertebrates and they are functionally blind. Photograph: Eric Ste Marie

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.