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Shapeshifting Cephalopods: Cuttlefish Falls in Line

A Common Cuttlefish (Sepia officinalis) lifts its arms upright (left) and at an angle to match stripes in an aquarium. The use of two-dimensional patterns allowed the researchers to precisely measure how well the arm positions corresponded to the backdrops—and to rule out the possibility that the animals were basing their configurations on touch, according to study co-author and cephalopod researcher Roger Hanlon.

And because the experiments were done in controlled aquariums, the researchers could be sure the cuttlefish weren’t reacting to chemical cues. Reaching about 17 inches (45 centimeters) long, the common cuttlefish changes its color and skin texture to evade predators, including marine mammals, fish, and seabirds.

“They have an enormous variety of predators, some of which have marvelously good visual capabilities,” Hanlon said. “That’s why the [cuttlefish] camouflage has to be so good.” (via: National Geo)

(photo: Justine Allen)

rhamphotheca:

Shapeshifting Cephalopods: No One Here But Us Plants

During recent research into how cuttlefish (and other cephalopods) adopt camouflage positions, a common cuttlefish (left) raises two of its eight arms in apparent mimicry of artificial algae placed in its tank. The animal reacted similarly when shown a photo of green algae, said biologist Roger Hanlon. It’s been known that many cuttlefish—and their squid and octopus cousins—adjust their postures and rapidly change color to resemble nearby objects, a strategy to evade predators.

But the recent lab experiments are the first to confirm that cuttlefish use visual information to determine those gestures, according to Hanlon, of the Marine Biological Laboratory in Woods Hole, Massachusetts.

“Camouflage is one of the least studied subjects in biology. It would be nice if our paper encourages folks to look at this behavior more carefully in other animals,” said Hanlon, whose new study was published May 11 in the journal Proceedings of the Royal Society B: Biological Sciences. (via: National Geo)

(photo: Roger Hanlon)

rhamphotheca:

Shapeshifting Cephalopods: The Squid and the Sea Fan 

Continuously jetting water out its back end to stay afloat, a wild Caribbean Reef Squid (Sepioteuthis sepioidea) appears to be an extension of a sea fan. Up close, the creature catches the eye, but “in the full-frame picture, that animal is very hard to see,” cephalopod researcher Roger Hanlon said. (via: National Geo)

(photo: Roger Hanlon)

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