Sea cucumbers are animals that live on seabeds and coral reefs. The texture of their body can be lumpy, bumpy, or even spiky. They are amazingly flexible, becoming as pliable as wax or as stiff as a board within minutes or even seconds. Such flexibility allows sea cucumbers to wriggle their way into tiny crevices and then stiffen so that predators cannot pull them out. The secret of the sea cucumber lies in its remarkable skin.

 Consider: The sea cucumber’s skin has three states—stiff, medium, and soft. To change between states, sea cucumbers link or unlink fibers in their skin. They do so by activating different stiffening or softening proteins.

 Stiffening proteins form tiny bridges, or chains, between fibers in the connective tissue, making the skin more rigid. Softening proteins unchain the fibers, making the skin softer. Sea-cucumber skin can become so soft that it seems to melt.

 Scientists are developing materials that mimic the adaptability of sea-cucumber skin. One of their aims is to create electrodes for brain surgery that are stiff enough to be placed in precisely the right spot but that will also then soften. Such adaptability in electrodes would reduce the likelihood that the body would reject them.

 What do you think? Did the smart skin of the sea cucumber evolve? Or was it designed?