Marine researchers have discovered the Atlantic longarm octopus mimicking not only the color and appearance of the peacock flounder, but also its unique style of swimming in order to convince predators it’s something it’s not.
By comparing film footage and photographs from the five Caribbean locations, the researchers saw that the Atlantic longarm octopus (Macrotritopus defilippi) was deftly mimicking a peacock flounders’ ( Bothus lunatus ) behavior and coloration. Octopus, a member of the cephalopod family, have evolved a unique skin system that can change color at will, however the researchers say the Atlantic longarm octopus is particularly skilled.
 Atlantic longarm octopus in the aquarium; note the long thin arms characteristic of the species. Photo by John Forsythe. |
“We were equally impressed with the remarkable camouflage of this small octopus species even when it was stationary yet entirely exposed on top of the open sand,” lead author Roger Hanlon, Marine Biology Laboratory Senior Scientist, said in a press release. “The apparent match in pattern, color, brightness, and even 3-dimensional skin texture was noteworthy even when compared to other changeable cephalopods. They also demonstrated an unusual form of disruptive camouflage.”
But the octopus changed its behavioral patterns as well as its appearance. Mimicking the peacock flounder’s characteristic swimming style, the octopus hugged its body to the seafloor and let its arms hang loosely behind as though it were the flounder’s tail. The octopus also swam in the odd start-and-stop pattern of a flounder.
 Atlantic longarm octopus swimming forward and mimicking the shape, speed, and behavior of flounder swimming. Photo by R. Hanlon. |
Researchers speculate that the octopus mimics the flounder to protect itself from predation. Potential predators would likely choose a soft octopus to attack over a firm flat flounder; however more research is need to confirm this.
While Hanlon has uncovered similar behavior of flounder-mimicry in two other octopus species in Indonesia, this is the first time the researchers observed the behavior in the Atlantic.
The study was published in the February issue of The Biological Bulletin.
Atlantic longarm octopus, Macrotritopus defilippi imitating a flounder.
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