Carrie Lamitie, age 12, of Delmar, N.Y., for her question:
WHY DOES AN OCTOPUS CHANGE COLOR?
We know, more or less, how the remarkable octopus switches his color schemes. But why he does this is somewhat more mysterious. Usually his outfit matches and blends in with his background but not always. Some experts suspect that he may, now and then, wear colors to express his emotions but nobody is sure of this.
The average octopus has a body like a bag of jelly, with a parrot beak and a large pair of stern eagle eyes. Around his mouth are eight supple tentacles, nicely studded with suckers that look like neat rows of round buttons. The arms are joined by triangles of delicate webbing and his arm spread may be ten feet wide.
Sometimes this unusual creature tippy toes along the ocean floor, looking for all the world like a blushing pink parasol. On these occasions he does not match his background, but it is not likely that the blushes are from
He has a built in wardrobe of almost unlimited color schemes and as a rule he wears one that perfectly matches his surroundings though not always.
The sea is a hungry place and the soft bodied octopus relies on disguises, concealment and camouflage. When not foraging for food, he retires to his safe rocky den, called a villa. For sudden emergencies, he carries a built in ink sac complete with syphon. When faced with an unexpected foe, he squirts out a jet of ink and escapes to his villa in a cloudy smoke screen.
His color changes are caused by pigmented and reflecting cells built into his jellified skin. There are two layers of colored bodies called chromatophores above layers that reflect blue, green or white light. In the top layer, the chromataphores vary from black to reddish brown. The second layer varies through red, yellow and pale orange.
The color bodies can swell, shrink and move around. Together they blend with changing reflections from below. With this assortment of artist's colors, he can blend a plain, spotted or blotched outfit to match almost any background in his watery world.
The amazing changes may be triggered by light or by other factors. Nobody is quite sure of these details. But we can be reasonably sure that almost always he changes colors to camouflage himself by blending in with his background.