The Greenland shark, a creature of immense longevity, has captivated the public's imagination for decades. With an estimated lifespan of over 400 years, some of these sharks were alive during the time of Isaac Newton, and they spend much of their lives with parasites attached to their eyes, leading to the belief that they are functionally blind. However, a recent study challenges this notion, revealing a more nuanced understanding of these fascinating creatures.
The initial belief that Greenland sharks are blind stems from a 1998 paper by Borucinska and colleagues, which suggested that a copepod parasite could lead to severe vision impairment. This idea gradually became a popular narrative, with the sharks being portrayed as tragic figures, drifting through the Arctic darkness, blind and ancient. However, a 2026 study by Lily Fogg and colleagues at the University of Basel and UC Irvine provides a different perspective.
The research, published in Nature Communications, presents comprehensive evidence that the Greenland shark retains an intact visual system well-adapted to dim conditions. The study examined the retinal tissue of the sharks and found no signs of degeneration, indicating that the molecular machinery for processing low light is present and active. The authors also identified DNA repair pathways in the retina that help preserve photoreceptor function across centuries.
This finding challenges the previous belief that the sharks are blind, suggesting that they can see through or around the parasites, which do cause some local damage to the cornea. The study highlights the importance of critical evaluation of scientific narratives and the potential for misinformation to spread, especially when dealing with creatures that live much longer than humans.
The author, the Space Daily Editorial Team, emphasizes the need for a more nuanced understanding of scientific discoveries and the potential impact of popular science writing on public perception. They argue that the story of the Greenland shark is a reminder of the importance of critical thinking and the potential for misinformation to shape our understanding of the world.
