Study Indicates Some Sharks Are Color Blind

A recent study by a group of Australian scientists has suggested that wobbegong sharks are color blind! Past studies that have tested color-sensing abilities in elasmobranchs (rays, skates, and sharks) have shown that some rays have color-vision, but it was believed that sharks were probably colorblind. This has now been proved in two species of wobbegong sharks and indicates the possibility of colorblindness in all sharks. But more species will have to be tested before conclusions can be drawn for more sharks.

The study looked at light-sensitive proteins in the light-sensing cells in the retina of wobbegong shark eyes. Different types of these light-sensing proteins, opsins, are used to detect various types of light and convert them into photoelectric signals. Animals usually need two types of opsins in order to have any color-vision. It was found that the two species of wobbegongs studied had only one cone opsin, concluding that their vision is colorblind. Many fish and other marine animals have color vision but this trait seems to be lost for certain types of whales, seals and dolphins, and it is unknown why large marine predators lost multiple opsins in their retina, and thus color vision. This new knowledge about wobbegong color sensitivity could have broader indications that many sharks are colorblind. This has important implications for the scuba, surfing and fishing industries, which can use this research to make their products less visible to sharks to promote diver, swimmer and surfer safety and make fishing lures that are more difficult for sharks to see in order to reduce shark by-catch!