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During World War I, military experts discovered that by using certain colors and patterns on ships, tanks, equipment, and clothing, they could make the objects blend into their backgrounds and seem to disappear. To describe this new technique, they borrowed from the French word camoufler (which means “to disguise”) and created the word camouflage.
Although the word was new, the principles involved were not. They have been used in the animal kingdom since the beginning of time by both the hunting and the hunted species. Even primitive man learned to camouflage himself in the skins of animals so he could get close enough to kill his quarry without giving alarm.
Natural coloration is probably the simplest and most effective type of camouflage
found in the animal kingdom. You will find that most creatures match or blend
with the colors of their surroundings and are most difficult to see as long
as they remain still. However, if they are moved from their natural habitats,
their protective coloration no longer camouflages or hides them.
For example, the white coat of the polar bear blends with the ice and snow of this animal’s natural habitat making the bear almost invisible. If the bear were moved to a woodland area, its white coat would be quite obvious against the woodland browns and greens. Likewise, if a woodland bear with its dark coloration were taken to the white habitat of the polar bear, it would not blend into its new surroundings.
Some animals such as the snowshoe hare actually change colors to match the seasonal color changes. The hare’s late spring and summer fur is made up of shades of brown, which blend into its woodland and prairie background. As its summer coat wears out, the brown fur is replaced with new white fur. Since this part-white—part-brown period occurs during autumn when early snow flurries often leave patches of white on the landscape, the hare continues to blend with its surroundings. By the time the snows of winter arrive and the ground turns white, the hare’s brown coat has been completely replaced with white fur, and only its dark eyes show up against the snowy background. As the white winter coat is shed, it is replaced with brown fur, and the hare is again ready for the browns of summer.
Rapid color changes can be accomplished by some animals when their background colors suddenly change. The anole lizard, which is mistakenly called a chameleon, is one of these quick-change artists. Its body coloration can range from pale green to dark brown. If a green anole lizard is placed on a dark tree trunk, within two or three minutes the creature can change its body color to match the color of the tree bark. Color changes also occur in response to temperature and light changes.
Another quick changer is the flounder. This fish is able to match not only the color of its background, but also the textured look of mud, sand, or gravel as well. To test the flounder’s changing ability, scientists have placed the fish in an aquarium with a glass bottom and then inserted various patterns beneath the glass. Whether the pattern contained stripes, polka dots, or even a checkerboard, the flounder changed its coloration to resemble as closely as possible these unusual backgrounds.
Some members of the animal kingdom are camouflaged not only by their color, but by their shapes as well. They may look like dead leaves, twigs, vines, seaweed, or other types of vegetation. One insect, the walking stick, so closely resembles a twig that it is possible for you to look directly at a motionless one and not be able to see that it is not a twig. The insect’s long slender body actually has spines and knobs that look like the buds and bumps on a small twig.
The brown caterpillar stage of many kinds of moths feed at night and rely on their color and shape to camouflage them from enemies during the day. All day long they stand rigid on a limb looking like small twigs. Irregular bumps along the body and a bud-shaped head complete the disguise. To rest while in this awkward position, the caterpillar sometimes spins an almost invisible thread around the twig to support its body at the correct angle.
Also camouflaged by color and shape is the sargassum fish. Spines and leaflike growths cover its body, and as it crawls through the Sargassum seaweed with its fins, only its blue eyes can be distinguished from the seaweed itself.
Animals also have defensive camouflage which serves to deceive, distract, or startle their enemies. The deceptive camouflage may take the form of vicious-looking head spines (which are really quite harmless) like the ones on the hickory horn devil caterpillar. To complete the deception, this caterpillar even makes menacing backward jabs with the useless spines to fool its enemies.
Large, startling eyelike spots appear on the thorax region of the swallowtail butterfly caterpillar to make the creature look like a small dragon. These fake eyes lead enemies to believe the caterpillar is larger and stronger than it really is and cause them to leave the defenseless caterpillar alone.
Another type of deceptive camouflage is mimicry, in which a harmless animal looks like a not-so-harmless or bad-tasting species. Birds quickly learn that monarch butterflies have an unpleasant taste and do not eat them. So, the viceroy butterfly, which is marked almost exactly like the monarch, benefits from its “copycat” coloring and is avoided by birds even though it has no bad taste and would make a nice meal for them.
Mimicry appears in the reptile world, too, and some of the best-known examples are the imitators of the poisonous coral snake. These imitators have the red, yellow, and black markings, but the color bands do not appear in the same order as those of the coral snake. As a result, to identify the coral snake, the rhyme “red and yellow, kills a fellow” is repeated to remind the observer that if the red and yellow bands of color touch each other, the reptile is indeed a poisonous coral snake. The other rhyme, “red and black, venom lack,” points out that the imitating snakes such as the Mexican, Louisiana, and western milk snakes, which have their red and black bands of color touching, are not poisonous.
Distracting camouflage can be quite varied. For instance, the large eyespots
on the lower wings of moths and butterflies serve to draw their enemies’ attention
to these areas and away from the soft body parts. A bird’s beak jabbed
into the wing’s eyespot damages the wing, but the moth or butterfly still
may be able to escape with only a tattered wing for the experience.
Certain types of lizards have colorful tail segments to catch the eyes of their enemies. As the predator strikes at the colored tail, the tail breaks off and the lizard is able to escape. With time the lizard will grow a replacement tail. Distracting camouflage also is used by the hunter. Some species of young copperhead snakes have a bright yellow tail segment that they twitch and wriggle to resemble a worm. When an unwary frog or lizard slips up to catch the yellow worm, the frog or lizard ends up being caught itself.
These are but a few examples of how camouflage is used by the hunted and hunter species to hide, frighten, or deceive each other as they attempt to survive from one day to another in nature’s eat-or-be-eaten world. For additional reading you might be interested in Animal Camouflage by Adolf Portmann (University of Michigan Press, Ann Arbor, Mich.) or Animal Camouflage by Dorothy Shuttlesworth (Doubleday and Company, Garden City, N.Y.).
1983 Camouflage. Young Naturalist. The Louise Lindsey Merrick Texas Environment Series, No. 6, pp. 24-27. Texas A&M University Press, College Station.