Scientists at the University of Texas at Austin found a species known as lookdown fish camouflage themselves through a complex manipulation of polarized light striking their skin.
The researchers put some lookdowns, which are known as good camouflagers, in tanks in a lab then simulated the sun passing over the ocean during the course of a day.
"The lookdown altered the properties of the polarized light it was reflecting so that it would be a better blend into its specific background at different times of day," biology Professor Molly Cummings said.
The study, published in the Proceedings of the National Academy of Sciences, was funded by the U.S. Navy, which has an interest both in developing better ocean camouflage technologies and in being able to detect such strategies if developed by others.
"The open ocean represents a challenging environment for camouflage," Cummings said. "There are no objects to hide behind in three-dimensional space, so organisms have to find a way to blend in to the water itself."
"From an evolutionary biologist viewpoint, I am always excited when evolution is one step ahead of humans," Cummings said. "There is this problem out there -- how to blend in to this environment, and though we haven't quite solved it yet, an animal has."