Octopus - Skin helps researchers in replicating Camouflage | update & learn

Octopus skin is showing camouflage, they use coloring, texture and markings to blend into their environments. Predators use camouflage to make it hard for their preys to see them sneak up.

In a flash, an octopus can make like ragged-edged seaweed or coral by changing the color and texture of its skin, thus becoming nearly invisible in its environment. And in the future, robots may be able to pull off this seemingly magical camouflage trick as well.

Researchers have created a synthetic form of cephalopod skin that can transform from a flat, 2D surface to a three-dimensional one with bumps and pits. Drawing on this tremendous adaptation for inspiration, researchers recently designed and created a camouflage-like material that can change its appearance when illuminated.

The skin of cephalopods, the class of animals that includes octopus and cuttlefish (and squid and nautiluses), includes three layers: The surface layer contains the pigments that control what the animals looks like; the middle layers contains muscles that can shift around the orientation of these pigment-containing cells and thus change the skin's color; and the bottom layer helps sense the color of its surroundings. The secret to cephalopods’ unrivaled camouflage lies within 3D bumps on the surface of their skin called papillae. In one-fifth of a second, the papillae can rise or retract, swiftly and reversibly morphing the animal’s surface into various textures like those belonging to seaweed or coral. The primary reason why the soft-bodied mollusks evolved this ability is for defense. Their flexible body has no bones so they can escape into small cracks, rocks, crevices, and even into bottles and cans from the seafloor. They can also use jet propulsion to quickly move through the water and escape predators. At the end of the day, however, these animals invested the most resources into camouflage because it pays off better to stay inconspicuous rather than constantly evade predators.

Octopi and cuttlefish are masters of disguise. Within a fraction of a second, they can morph their tissue and seamlessly blend with their surroundings, becoming indistinguishable from a rock or coral, for example. Taking cues from nature, researchers at Cornell University have devised their own ‘camouflage skin’ which stretches and morphs in 3D. The skin can be programmed to take all sorts of shapes.

In designing the new camo-material, researchers drew on this layered set-up. The bottom layer senses background color (for now, just black or white) using electrodes. This information is transferred to the middle layer, consisting of actuators (a type of motor) that can heat up if the background is white or the sheet is illuminated. The top layer consists of black pigments that turn transparent under heat; so if the sheet is illuminated with white light, the actuators will heat up and it will appear white. Otherwise, in the dark, it stays black.

Cephalopods’ exceptional ability to hide into any background has inspired researchers to replicate their fascinating ability to camouflage in the infrared (IR) and visible spectrum. Recent advances offered a number of physical mechanisms to reproduce the cloaking functionalities of cephalopods. However, most of works focused on either camouflaging in the visible or IR camouflage range only: not dual modes in a single device structure that can readily switch between the visible and IR mode according to a suitable situation.