The tendons behind the suckers have also transformed into mirrors to reflect the light outward. About half of the suckers glow continuously while the other half switch on and off. It's almost hypnotic. Without sucking suckers, Johnsen speculates that the octopus may ensnare its food in a net of mucus as some other sea creatures are known to do. An Evolutionary Tale As for why the suckers turned into light bulbs, the move to the deep ocean probably spurred the change.
Most octopuses live in shallow waters, where grabbing prey and holding on to the bottom is useful.
The blue-green glow is precisely the color that travels farthest through water. Because there's no fossil record of bioluminescence, it gives us a rare glimpse into the evolutionary history of light production. The glowing suckers of a deep-sea octopus offer a glimpse of evolution in progress. ABC News Internet Ventures. All rights reserved.