Japanese Scientists Discover Cuttlefish Can Change Color Instantly to Blend into Their Surroundings, Evading Predators.
Previously, only two groups of cephalopods, octopuses and nautiluses, were known for their ability to camouflage into their environments by changing their body colors. However, a new study published in the journal Scientific Reports last week has added cuttlefish to this list.
The discovery was made in a laboratory by biologists from the Okinawa Institute of Science and Technology (OIST) in Japan. It opens up a new avenue of research into how cuttlefish see and perceive their surroundings, which could contribute to conservation efforts.
Experiment testing the color-changing ability of the Shiro-ika cuttlefish. (Video: OIST)
Cuttlefish in the wild prefer to inhabit the vast open ocean, where their bright skin blends perfectly with the clear water and the dappled sunlight above. As a result, very few people have the opportunity to observe the behavior of cuttlefish on the ocean floor. Their elusive nature also makes laboratory research challenging. This is why scientists were unaware of their color-changing ability until now.
The OIST discovery came about accidentally while researchers were cleaning algae from the bottom of an aquarium in the lab, where they were raising a local species of cuttlefish known as Shiro-ika. This species is one of only three oval-shaped cuttlefish (leaf cuttlefish) found in the waters off Okinawa.
This cuttlefish displays varying shades of color in areas of the tank with different algae densities.
Upon closer observation of the cuttlefish at the bottom of the tank, they noticed that the animals exhibited different shades of color in areas with varying algae densities. Intrigued by this, the research team conducted a controlled experiment to better understand what was happening. They cleaned half of the tank and left the other half covered in algae, then set up a camera to observe the subsequent developments. As expected, the Shiro-ika cuttlefish rapidly changed its body color from light to dark when swimming from the clean section to the algae-covered section, and vice versa.
“This effect is truly impressive. I am amazed that no one had recognized it before,” said Dr. Zdenek Lajbner from OIST, the first author of the study. “It shows how little we know about marine animals like cuttlefish.”
This new finding is significant not only for cuttlefish but also for the ecosystems they inhabit. Lajbner believes that if the surrounding environment is crucial for the camouflage of cuttlefish, fluctuations in the population of this cephalopod group could be related to the health of coral reefs.
