14 DAY TRIAL // Investigators analyzing the eyes of sharks have determined that the organs only contain a single type of cone cell, which means that the marine animals might in fact be color-blind. They are therefore completely incapable of sensing colors.
This is weird, experts say, given that some of the closest genetic relatives to the shark, such as for example rays and chimeras are capable of experiencing some color vision. The new study was conducted by experts at the University of Western Australia (UWA).
UWA researcher Dr. Nathan Scott Hart collaborated closely with colleagues from the University of Queensland in Australia (UQ) for the research, which also reveal that sharks' eyes can function over a wide range of light levels.
Still, the animals only carry a single, long-wavelength-sensitive cone type in their retina, the team reports in a paper published online in Springer's scientific journal The Science of Nature.
“This new research on how sharks see may help to prevent attacks on humans and assist in the development of fishing gear that may reduce shark bycatch in long-line fisheries,” Hart explains.
“Our study shows that contrast against the background, rather than colour per se, may be more important for object detection by sharks,” the expert goes on to say.
“This may help us to design long-line fishing lures that are less attractive to sharks as well as to design swimming attire and surf craft that have a lower visual contrast to sharks and, therefore, are less ‘attractive’ to them,” he adds.
The new study is somewhat surprising in that it kind of takes sharks down from their pedestal as some of the most fit hunters in the world. Until now, experts believed that sharks' amazing evolutionary success was based on their highly-adapted sensory systems, vision included.
But now it would appear that the sharks actually rely on other mechanisms as well, whose actions combine to allow the creatures' effectiveness in hunting, AlphaGalileo reports.
“While cone monochromacy on land is rare, it may be a common strategy in the marine environment,” the authors of the new paper write in the journal entry.
“Many aquatic mammals – whales, dolphins and seals – also possess only a single, green-sensitive cone type,” they add.
“It appears that both sharks and marine mammals may have arrived at the same visual design by convergent evolution, in other words, they acquired the same biological trait in unrelated lineages,” the experts conclude.