How Do Glowing Sharks See in the Dark? New Surprises Revealed

Deep-sea sharks wield some surprisingly well-adapted eyes that help them see in the dark, according to new research.

Transparent patches of skin above their eyes and a unique arrangement of light-sensitive cells on their retinas, among other things, allow five species of bioluminescent deep-sea shark to collect and focus as much light as possible to hunt prey and find each other in the gloomy depths.

These discoveries are helping to overturn a long-held view that sharks rely heavily on smell to get around.

“Historically, sharks have been considered to have poor eyesight,” said Tom Lisney, a sensory ecologist at Queen’s University in Kingston, Ontario, who wasn’t involved in the research.

Fairly recently, though, studies have shown that that might not be the case.