Greenland sharks are spilling new secrets about antiaging.

In the deep, dark waters of the Arctic and North Atlantic, these ghostly giants — which can live for centuries — have hit upon a few tricks for surviving long-term. Some of their organs may be resistant to the ravages of age, while others seem resilient to tissue damage that accrues over time, recent studies suggest.

The findings offer some glimmers into how these sharks manage to live longer than all other vertebrates on the planet. It’s work that could one day lead to therapies for treating aging organs in people, says Lily Fogg, a biologist at the University of Basel in Switzerland. That’s the “ultimate dream goal,” she says.

Scientists estimate that Greenland sharks (Somniosus microcephalus) may survive for upward of four hundred years. “They’re these huge, ancient grandpa sharks,” Fogg says. But it’s unclear how exactly their bodies keep on cruising decade after decade. Fogg’s team studied the animals’ eyeballs. No one knew if the sharks had much vision, let alone if that vision degraded over time. The common thinking was that the sharks were either severely visually impaired or completely blind, Fogg says. She and her colleagues examined eye tissue from 10 Greenland sharks, some up to about 150 years old. The animals had all the cellular and molecular tools in place for seeing in the deep sea’s dim light, the team reported in Nature Communications.

The tissue also looked like it had avoided the typical wear and tear of aging. That may be due to dialed-up activity of DNA repair machinery in the eyes, Fogg says. This machinery fixes damage that can lead to cell death and tissue degeneration. An earlier investigation of the Greenland shark’s genome also pointed to enhanced DNA repair function, reported physiologist Alessandro Cellerino and his colleagues.

The antiaging strategy at work in the eyeballs may not occur in all the Greenland shark’s organs, however. Researchers studying the animal’s heart found that it appears to collect the typical scars and stresses that time tattoos on our tissues, scientists reported December 23 on bioRxiv.org. “We were expecting the opposite,” says Cellerino, of the Scuola Normale Superiore in Pisa, Italy.