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The octopus has a unique ability to change the color and texture of his skin. A recently presented technology can now replicate this skill.
Last year, a paper published in Nature magazine showed that, because of their unusual amount of protein-coding genes and the ability of their tissues to modify proteins to change their function, octopuses were probably the closest thing to an alien form of life on Earth. Other distinguishing traits such as their great intelligence—they possess nine independent brains, one per tentacle—and their uncanny ability to learn and remember, place them in a whole different category compared to other invertebrates.
Recently, a group of scientists discovered what looked like an actual octopus city, which was named “Octlantis”, where a group of fifteen octopuses had built their own homes aided by sand and seashells. Another fascinating quality is the way they can transform their color and texture in tenths of a second. For instance, they can mimic a crab displaying his courtship repertoire to attract unfortunate crustaceans. Inspired by this advanced form of mimicry, a group of scientists and engineers from the Cornel University (US), together with Roger Hanlon, an octopus scholar, have developed a new technology. Back in 2014 they had already described the camouflage techniques employed by these cephalopods in the Journal of Morphology. Now, however, they are aiming to replicate them.
The new system, which was announced in Science magazine, involves a thin silicon membrane that can adopt complex 3D shapes. The pneumatically-activated material simulates the papillae of an octopus, which resemble “balloons” and are composed of muscular tissue without an underlying bone structure, in a similar fashion to the human tongue. For example, the papillae of squids can take half a dozen shapes, from conical to trilobular, and be retracted in a fifth of a second so the animal can swim freely. “We were drawn by how successful cephalopods are at changing their skin texture, so we studied and drew inspiration from the muscles that allow cephalopods to control their texture, and implemented these ideas into a method for controlling the shape of soft, stretchable materials", says lead author James Pikul, an assistant professor in the Department of Mechanical Engineering and Applied Mechanics at the University of Pennsylvania.
The membrane developed by Pikul and his team can be programmed to replicate different shapes, like those of stones or plants. A robot covered with this membrane could thus mimic its environment. Camouflage, however, isn’t the only feature of this membrane, as these changes in texture could allow it to absorb an increased amount of light and, therefore, warm up the structure.
Although this membrane is one of the most sophisticated cephalopod-inspired camouflage technologies developed so far, it is by no means the only one. In 2014 a team from the University of Illinois led by Prof. John Rogers presented their own optoelectronic camouflage prototype. The system could detect light and alter its own colors according to the environment. Unfortunately, in its first iteration it could only detect grayscales and its practical applications were much more limited than the technology proposed by Pikul and his team.