Scientists now know what it’s like to see through the eyes of a shark.
In the past five years or so, research has shown that many different types of fish, rays and sharks can fluoresce, producing brightly colored light when illuminated by even dim sunlight. It isn’t yet clear, however, whether they can actually see this fishy glow or what purpose this trait serves.
To find out, John Sparks, a curator of ichthyology at the American Museum of Natural History, his colleague David Gruber and others examined the eyes of two different kinds of sharks that live at depths of around 100 to 150 feet, and whose skin produces a bright-green glow. In the laboratory, they took shark eyes, shined light on them and then measured the wavelengths of light absorbed. They found that these two species—the swell shark (Cephaloscyllium ventriosum) and the chain catshark (Scyliorhinus retifer)—can see bright green, the color of fluorescent light their skin produces.
“This is the first paper to show that a fish eye is capable of absorbing” this biofluorescence, says Sparks, the senior author of the study, published April 25 in the journal Scientific Reports.