Cuttlefish Change Color, Shape-Shift to Elude Predators

Dave Hansford in Wellington, New Zealand
for National Geographic News
August 06, 2008

Cuttlefish have been captured on film exhibiting sophisticated camouflage strategies at night, according to scientists who are using new high-resolution cameras to bring these dramatic changes into focus.

They are also using underwater spectrometers to measure color wavelength to determine how other marine creatures perceive these shifts.

The findings are helping to crack the code of cephalopods, including cuttlefish, which also employ shape-shifting strategies to conceal themselves as coral or algae.

Each summer, giant cuttlefish—molluscan relatives of octopuses and squid—gather along spawning grounds off the south Australian coast.

For the last nine breeding seasons, Roger Hanlon, senior scientist at the Marine Biological Laboratory at Woods Hole, Massachusetts, and a National Geographic Society grantee, has closely studied their camouflage strategies. (National Geographic News is owned by the National Geographic Society.)

His work takes place at a cuttlefish spawning site—a five-mile (eight-kilometer) stretch of shallow, flat reef—in Spencer Gulf, Australia.

This summer Hanlon went back to Australia with collaborators from the University of Sydney and the University of Queensland and used an autonomous underwater vehicle, or AUV, with a pair of high-resolution cameras and a powerful strobe to take detailed pictures of the concealed cuttlefish at night.

The cameras were synchronized and aimed at the same spot so they captured three-dimensional images.

Researchers want to know if the cuttlefish have taken their extraordinary talent for camouflage to the next step by employing color wavelengths invisible to their predators.

One of Hanlon's co-researchers, Professor Justin Marshall of the University of Queensland, used a sophisticated underwater spectrometer. "It tells you every [color] wavelength present, and how much there is of it," Hanlon said.

He hopes the device will help reveal just how closely the cuttlefish's camouflage coloration matches their surroundings.

Then, the pair will take that data this fall and superimpose them over what they know of fish color vision. This will allow them to determine how well the color of the cuttlefish matches the color vision spectrum of their predators, Hanlon explained.

Continued on Next Page >>


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