Greenland sharks live centuries with functional eyes, debunking blind myth

New research shows that Greenland sharks retain a working visual system even after living for up to four centuries, overturning the long-standing belief that they are blind.

Scientists have now proven that Greenland sharks, which can live for nearly four centuries, maintain a functional visual system throughout their lives. The conclusion comes from a 2026 Nature paper that combined genomic, transcriptomic and histological techniques, showing healthy rod cells, active phototransduction genes and no signs of retinal degeneration in sharks older than a hundred years. Earlier research in 2016 established the species as the longest-lived vertebrate, while a 1998 study on the copepod Ommatokoita elongata suggested possible visual impairment, a claim that gradually morphed into the belief that the sharks are blind.

Direct testing of corneas from parasitized sharks demonstrated that light still penetrates to the retina. Researchers propose that elevated expression of DNA-repair genes in the eye may preserve vision over such extreme lifespans, a mechanism also seen in bowhead whales. The discovery overturns the myth of a blind, ancient drifter and opens new questions about why the sharks retain sight. It highlights how assumptions about obscure deep-sea species can persist without direct testing.