Scientists found that Greenland sharks keep working retinas for more than a century, hinting at a built-in repair system that protects vision in the deep dark ocean.
Story Snapshot
- Peer-reviewed study shows intact, light-sensitive retinas in very old Greenland sharks
- Retinas appear tuned to blue light, matching deep, low-light waters
- DNA repair genes ercc1 and ercc4 are retained or elevated, pointing to protection of retinal cells
- Sampled sharks were 100–134 years old; results support preserved vision into extreme age
What the new research actually found
Nature Communications published a study reporting healthy retinal structure and function in adult Greenland sharks. The team used genomic, transcriptomic, and tissue analysis of shark eyes. They found rod cells that respond to dim light and rhodopsin tuned for blue wavelengths common in deep water. The authors concluded the visual system remains functional and adapted to low light in very old animals, which are famous for extreme lifespans that can near four centuries.
Coverage of the work adds that the retina is sensitive around 458 nanometers, which is in the blue range. That tuning fits the sharks’ cold, deep habitats, where blue light travels farthest. Rod-only retinas trade color vision for better light capture. This setup helps a slow-moving predator detect contrast and motion in near darkness. Reporters noted that the team studied eyes from deceased sharks and still found signs of working visual pathways.
How the sharks may protect their eyesight
The study links preserved retinas to strong DNA repair. The authors report that sharks with long lifespans keep the ercc1 gene, and the Greenland shark shows higher expression of ercc4, also called xpf. These genes work together in a repair complex that fixes DNA damage. The paper suggests this activity helps maintain retinal integrity for unusually long periods, even though it stops short of proving direct cause in living sharks across centuries.
Researchers did not report obvious retinal decay in the very old individuals they examined. That matches the gene findings and supports a picture of long-term eye health. An industry outlet summarized the sample as 10 deceased sharks, aged 100 to 134 years. That places the evidence in truly old animals, even if not the very oldest found in the wild. The authors focus on what they measured: structure, gene activity, and light-response features in the eye.
Why this matters beyond marine biology
This result pushes back on a popular myth that Greenland sharks are blind due to cloudy corneas. Parasites can harm the cornea, but the retina deeper inside can still work. That matters for how we think about aging. If repair pathways protect the shark retina, researchers may learn new ways to slow eye aging in people. The study shows a careful, testable route for follow-up work on genes that keep sensitive neurons alive.
Readers should separate the firm findings from the headlines. The paper shows preserved retinal function in very old sharks and a likely role for DNA repair. It does not claim a proven causal chain over 300 or 400 years, and it did not test behavior across a single shark’s full life. Still, the data give a rare look inside an animal that ages slowly and keeps its vision system ready for the deep’s thin light.
How to read the headlines with care
Science news can inflate early findings, especially with rare species that are hard to sample. Here, the core evidence is strong on the retina and on gene pathways. The bigger leap, “centuries of vision,” rests on the species’ known longevity and on results from sharks over a century old, not four. That does not weaken the main point. It simply marks where the data end and where cautious inference begins, which is standard good practice.
For people tired of hype, this is a case where the lab work carries the story. The team published in a respected journal, used multiple methods, and tied gene activity to tissue health. That is how progress should look. It also shows how nature solves problems our systems often fail to fix. In a time when many doubt big institutions, a careful, open study like this earns trust the old way: by showing the work and letting the facts speak.
Sources:
sciencedaily.com, nature.com, phys.org, pmc.ncbi.nlm.nih.gov
