Two deep-ocean species of cephalopod, an octopus and a squid, can go from transparent to opaque in the blink of an eye, a new study finds.
This impressive camouflage swap is an adaptation that likely keeps the cephalopods safe from two different types of predators. The first are deep-sea creatures that hunt by looking upward for prey silhouetted against the light filtering down through thousands of feet of water. The second are fish that spotlight prey in “biological” headlights. These fish use bioluminescence, their own body-driven light source, to hunt for food.
To avoid being seen as a dark silhouette, it pays to be transparent, said study researcher Sarah Zylinski, a postdoctoral scientist at Duke University in North Carolina. But when a bioluminescent light hits a transparent surface, the effect would be like a flashlight shining on a windowpane at night, Zylinski said: very reflective, and extremely obvious.