U.S. marine scientists say squid are masters of disguise, using their pigmented skin cells to camouflage themselves nearly instantaneously from predators.
Researchers at the Marine Biological Laboratory say squid can also produce polarized skin patterns by regulating the iridescence of their skin, possibly creating a "hidden communication channel" visible only to animals that are sensitive to polarized light.
Researchers Lydia Mathger and Roger Hanlon say they found the polarized aspect of the skin of the longfin inshore squid, Loligo pealeii, is maintained after passing through the pigment cells responsible for camouflage.
While the notion that a few animals produce polarized signals and use them in communication is not new, Mathger and Hanlon's findings present the first anatomical evidence for a "hidden communication channel" that can remain masked by typical camouflage patterns.
The say their findings suggest it might be possible for squid to send concealed polarized signals to one other while remaining camouflaged to fish or mammalian predators, most of which do not have the ability to recognize polarized light.
The research appears in the journal Biology Letters.