Well-Armed Creature - octopus luminescence - Brief Article

National Wildlife, Oct-Nov, 1999

When is an octopus sucker not really a sucker? When it glows and is not capable of sticking to surfaces. That's one of the recent discoveries by marine biologist Sonke Johnsen and colleagues at Harbor Branch Oceanographic Institution in Florida about the deep-water octopus Stauroteuthis syrtenis. As the creature (below) roams the waters off the U.S. East Coast, it twinkles in the dark depths as if its eight arms were adorned with lines of blue-green Christmas lights.

Luminescence has been found in many marine creatures, but until now the only octopuses known to glow in the dark were females of a few, very different species that lit up around their mouths prior to mating. Why the suckers light up is still anyone's guess. They may help the octopus lure prey: One study subject brought up from the deep had dined most on very small crustaceans rather than fish or other larger meals. Perhaps the blinking lights attract so many little snacks that the effort of catching bigger prey-along with the sucking ability of the suckers-is unnecessary. Johnsen also speculates that the lights may help the octopuses communicate with each other.