The octopuses are seen with leather

The Journal of Experimental Biology has published two studies, the authors of which found the open -legged mollusks of the opsine photosensitive pigments, which is usually contained in the retina. This means that cephalopods are able to see (at least react to light) with skin. Thomas W. Cronin from the University of Maryland and his colleagues studied Kalmar species ( Doryteuthis Pealeii ) and Caracatic ( Sepia Officinalis and Sepia Latimanus ). Desmond Ramirez and Todd Okley from the University of California at Santa Barbar worked with Octopus Bimaculoides .

For a long time, scientists have noted that chromatophores - pigment cells in the skin of cephalopods - are able to expand in response to lighting. Moreover, this happens when the light falls only on the skin, without falling into the eyes of the animal. Each chromatopher contains an elastic container with the granules of the pigment, surrounded by a ring muscle capable of contracting or relaxing, changing the volume of chromatophore. Back in the 1960s, a hypothesis arose that such a behavior of chromatophores is possible both at the command of the brain and autonomously. Ramirez and octries in detail studied this phenomenon on the samples of the skin of the octopus, fixed in Petri's cups under light -emitting diodes with different wavelengths. Scientists found that chromatophores quickly expanded and remained enlarged, rhythmically pulsating, when exposed to continuous bright white light. On the contrary, the red light caused slow, rhythmic muscle contractions, but not the expansion of chromatophores.

The most sensitive chromatophores were 480 nanometers long, which corresponds to the blue light. Some of the photosensitive pigments of opsins in cones - the mesh cells react to the same waves. Therefore, Ramirez and Okli suggested that these opsins are present in the skin of the octopus. They confirmed this fact using antibodies in which the fluorescent protein gene is built. These antibodies recognize opsins and contact them. In the study of Kronin, using a polymerase -concept reaction, activity was discovered in the skin of cephalopods encoding the photosensitive protein of rhodopsin, as well as another protein - retinochrome, usually working in the retina.

In the eyes, photosensitive proteins are located in an organized manner inside photoreceptors, so they create an exact image of what they saw. In skin chromatophores, they are located freely, and therefore photosensitive skin can detect changes in the brightness of light, but not to distinguish a detailed image.

Previously, scientists found similar skin properties in multi -shaped seaworms from the Nereida family. These creatures were able to hide from light into the shadow, even being beheaded.