Ancient greenland sharks keep sharp vision for centuries, defying scientific assumptions

Scientists have discovered that Greenland sharks—Earth’s longest-living vertebrates that can survive over 400 years—maintain functional vision throughout their extraordinary lifespans, overturning long-held beliefs about these ancient ocean dwellers.

For decades, researchers assumed these massive Arctic sharks were nearly blind. Living in the frigid depths of the North Atlantic and Arctic Ocean’s twilight zone, 200 to 1,000 meters below the surface, Greenland sharks inhabit a world of perpetual dimness. Many also carry eye parasites, further reinforcing the theory that they relied primarily on other senses to navigate their dark underwater realm.

However, groundbreaking research led by fish vision expert Lily Fogg at the University of Basel has revealed a different story. When shark biologist John Fleng Steffensen—who originally discovered the species’ incredible longevity—offered preserved shark specimens for study, Fogg’s team made a remarkable discovery. By analyzing the sharks’ genetic material, they found that genes responsible for vision remained intact and fully functional, even in century-old specimens.

Perhaps even more surprising, detailed examination of the sharks’ eye tissue showed pristine structural integrity. “We found that it’s actually beautifully intact,” Fogg explained. This discovery suggests that these remarkable creatures not only live for centuries but maintain their ability to see clearly throughout their extended lives, challenging our understanding of aging in one of nature’s most enduring species and highlighting how much we still have to learn about life in the deep ocean.