Sudan Vision Daily
Fearsome-looking creatures that live in the near-dark to pitch-black waters of the deep sea, dragon fish wouldn’t seem to have much need for eyes, let alone the ability to see color. However, some dragon fish have rapidly evolved from blue-light sensitivity to red-light sensitivity, and then back to blue again.
The deep sea is not the sort of environment that would appear to encourage rapid evolution. “It doesn’t change. It is always dark,” said study researcher Christopher Kenaley, a comparative biologist at Harvard University. “There is something else down there that is driving the evolution of the visual system.”
The force driving these changes is likely the bioluminescenceproduced by the dragon fish themselves as well as by other deep-sea creatures, he said.
Dragon fish, which have outsized jaws and teeth that belie their small size, live between about 650 to 6,600 feet (200 to 2,000 meters) beneath the ocean’s surface. About 95 percent of animals in that region can see blue light, which the creatures also produce through bioluminescence. Deep-sea animals, including dragon fish, glow in order to lure prey, communicate with one another or camouflage themselves against the dim light from the surface. Some dragon fish sport lures known as barbels with glowing fibers that resemble blue fiber-optic lights.