Greenland Sharks Keep Perfect Vision for 400 Years

Imagine keeping perfect vision for 400 years. Greenland sharks, the longest-living vertebrates on Earth, have cracked the code to centuries of clear sight in complete darkness.

Scientists long assumed these Arctic dwellers were nearly blind. They live 10,000 feet below the ocean's surface where sunlight never reaches, and many carry eye parasites that latch onto their corneas. It seemed impossible they could see much at all.

A team of researchers recently examined eyeballs from ten Greenland sharks caught off western Greenland between 2020 and 2024. The sharks ranged from 100 to 134 years old. What they found stunned them.

"I opened the package, and there was a giant, 200-year-old eyeball sitting on dry ice just staring back at me," recalls study co-author Emily Tom from the University of California, Irvine. The ancient eyes showed zero signs of degeneration.

The research team discovered Greenland sharks see exclusively in black and white through rod cells that work perfectly in dim light. While they can't see colors or fine details, their vision remains functional throughout their entire lifespan, which can stretch to 400 years.

The real breakthrough came from studying the sharks' DNA. Two genes, ERCC1 and ERCC4, code for proteins that continuously repair damaged DNA in their eyes. Only the longest-lived shark species carry the ERCC1 gene, and Greenland sharks produce unusually high amounts of ERCC4 proteins.

These slow-growing creatures add less than half an inch per year but eventually reach over 20 feet long. Their metabolism runs at a glacial pace, perfectly adapted to the freezing Arctic waters they call home.

Why This Inspires

This discovery opens doors scientists barely knew existed. Understanding how Greenland sharks maintain healthy vision for centuries could revolutionize treatment for age-related eye diseases in humans.

"We can learn so much about vision and longevity from long-lived species like the Greenland shark," Tom explains. The research team believes their findings could lead to new therapies for macular degeneration and glaucoma, conditions that rob millions of people of their sight as they age.

Evolutionary biologist Lily Fogg from the University of Basel notes the study happened almost by accident when a colleague offered leftover specimens from another project. Sometimes the most important scientific breakthroughs come from simply saying yes to unexpected opportunities.

A creature that survives in crushing darkness for four centuries without losing its vision reminds us that nature still holds countless secrets waiting to improve human lives.