Greenland sharks defy aging with 400-year-old supercharged vision in Arctic darkness

The Greenland shark, a remarkable creature with exceptional vision, is the world's longest-living vertebrate, surviving over 400 years in the Arctic's icy depths. A study published in Nature Communications reveals that these ancient creatures possess remarkable vision, despite living in near-total darkness and hosting parasites on their eyes.

Greenland sharks inhabit the freezing, pitch-black waters of the Arctic and North Atlantic. Yet, their eyes remain functional, defying expectations about aging and cellular decay. Their retinas contain 41% DHA, a molecular antifreeze that keeps membranes fluid in sub-zero temperatures, ensuring their vision stays sharp even after centuries.

Their eyes are packed with elongated rods, designed to capture the faintest traces of blue light—the only wavelength that reaches the deep ocean. The visual pigment in these rods is finely tuned to this specific light, allowing the sharks to detect movement in the gloom. Even more surprising, a parasite called Ommatokoita elongata, often found dangling from their corneas, does not seem to impair their sight.

Researchers also discovered a DNA repair mechanism that preserves the sharks' vision over their extraordinarily long lives. This finding challenges the assumption that cellular decay is inevitable with age. However, as of February 2026, the 2016 revelation about their visual abilities has not directly influenced studies on other long-lived marine species, such as whale sharks or manta rays. Current research on those animals continues to focus on genetics, ecology, and aging rather than vision.

The Greenland shark's ability to see in extreme conditions offers new insights into biological aging and deep-sea survival. While the discovery has not yet shaped broader marine research, it highlights how little is still known about the adaptations of Earth's oldest animals. The study remains a key reference for understanding longevity in the natural world.