Like all coleoid cephalopods, Humboldt squid (also known as jumbo squid) can change the color of their skin. Scientists have known the "how" of it—they employ organs called chromatophores—but little about why. Recent Stanford research offers new clues.
By outfitting squid with National Geographic's Crittercams, which are capable of recording audio, environmental and video data in low light, scientists at Stanford's Gilly Lab in Pacific Grove, Calif., captured footage of free-swimming squid changing color from red to white up to several times per second, in a behavior that researchers call flashing. New analysis of the footage published in the Journal of Experimental Biology suggests that the flashing is a way of communicating with other squid. "We only saw them doing it when other squid were around," says doctoral student Hannah Rosen, the lead author of the paper. "These are social animals. They swim in schools, and there's even evidence that they hunt cooperatively, so we think they're using color to communicate."
Photo: Courtesy National Geographic RemoteAnother color-changing behavior, called flickering, appears to camouflage the squid in the middle depths of the ocean, where there are no rocks or other objects to blend in with. "The patterns they form on their skin look like the patterns the light makes on the bottom of a swimming pool," says Rosen.
The research team hopes to deploy camera-wearing squid off Baja California this summer to learn more about how sophisticated their colorful communication might be. Notes Rosen, "Cephalopods have the largest brain-to-body ratio of all invertebrates. We can't even imagine all the things they can do."
