The octopus' clever camouflaging ability has been known for years, but the mechanics of it have been little understood. They can change the pigment in their skin almost instantaneously to reflect the environment around them. Two studies to be published in the Journal of Experimental Biology suggest that there's something truly amazing at play here: the octopus can sense light in its skin.
Cells called opsisn that are typically associated with the eye previously have been found in the skin of cuttlefish, a closely related cephalopod. The opsins are located within pigment cells called chromatophores, which are responsible for the ability to change color. Similar experiments revealed the cell functions in squids, too.
, a team at University of California, Santa Barbara delved into the abilities in octopuses. The octopus keeps its opsins in small fibers in the skin, rather than in chromatophores, they found. So, instead of living in the cells, the opsins act like a sort of small antenna, detecting light and communicating that information to the chromatophores, which then respond accordingly. The most sensitive responses came from blue light, which happens to be the spectrum that scatters the most in water, giving it its blue appearance.
This discovery adds on to the great and wonderful mystery of the octopus, which, despite being more closely related to mollusks like the snail and the clam, displays a remarkable amount of intelligence putting it up there with crows, chimps, dolphins, elephants, and other animals capable of higher-level cognition.
Octopuses ... what can't they do?