Camouflaging Squid Caught on Cam in Japan, First Time to be Observed in Lab

While squids are known to change color underwater, it was a first to actually observe this behavior in a lab setting in Japan by a team of scientists from the Okinawa Institute of Science and Technology Graduate University.

Thousands of color-changing cells called chromatophores, found in a wide range of animals including amphibians, fish, reptiles, crustaceans, are also present in cephalopods such as squids. The same cells allow animals to communicate with each other and blend in the wild.

The species of oval squid namely the Sepioteuthis lessoniana had never been observed doing this type of environmental camouflage, until the team captured a video of them changing color to hide in plain sight, Gizmodo reported.

The details of the study was published last week in Scientific Reports.

It's a Match!

In a matter of seconds, Coleoid cephalopods camouflage to match their visual surroundings, although this behavior is more commonly observed in benthic cuttlefish and octopus.

"Squid usually hover in the open ocean but we wanted to find out what happens when they move a bit closer to a coral reef or if they're chased by a predator to the ocean floor," said Ryuta Nakajima, a biologist at University of Minnesota Duluth and the lead author of the paper, in an Okinawa Institute release. "If substrate is important for squid to avoid predation, then that indicates that increases or decreases in squid populations are even more tied to the health of coral reef than we thought."

In the new study, findings show that squid can and will camouflage by matching the color of a substrate to avoid predators.

In a laboratory-based experiment, the scientists were able to record the squid's camouflaging abilities, from light to darker color. This squid, locally known as Shiro-ika, is one of three oval squids found in Okinawa. Since they are notoriously hard to keep in captivity, it is perhaps safe to say that this kind of research is rare and a first. However, researchers suspect that when it would be a different story entirely in their natural habitat or in the ocean floor.

Camouflaging Abilities Never Seen Before

The oval squid at the OIST's Marine Science Station was "almost accidentally" observed camouflaging to the substrate for the first time while researchers were cleaning their tank to remove the algal growth. A subsequent observation shows that the squid in the clean side of the tank appears to be lighter in color, but when they were above the algae, they immediately turned darker.

This controlled experiment uncovers ability that had never previously been reported in squid, "opening up exciting avenues for exploring the visual capabilities of the animal," the study suggests.

"This effect really is striking. I am still surprised that nobody has noticed this ability before us," said another first author, Dr. Zdenek Lajbner. "It shows just how little we know about these wonderful animals." This particular squid originally discovered by local fishermen long before the scientists, shows importance for Okinawa "for economic and cultural reasons."

According to senior author Prof. Jonathan Miller, Principal Investigator of OIST's Physics and Biology Unit, they look forward to exploring the squid's camouflage abilities and cephalopods in general.