Kidspace: The animal masters of disguise
Without using mirrors or makeup, they blend in, mimic, and confuse predators or prey.
As Marion Larson walked down the dirt road, she saw little balls of brown- and black-speckled fluff moving around. "They were baby ruffed grouse!" she exclaims. As she got closer, mother grouse started clucking and pretending her wing was broken, to lure Larson away from the chicks. "I moved toward her," Larson says, "but then I started back to the little ones." Mother grouse changed her tactics. She made a different cluck: Instantly, the young ones stood still.
"It was as though they'd disappeared," says Larson, Outreach Coordinator for the Massachusetts Division of Fisheries and Wildlife. "They were there in front of me one second. Then they were gone. They didn't run away; they just froze. All I could think of was, 'Wow, camouflage really works!' "
If you are a predator in the wild, such as an Arctic fox, camouflage helps you sneak up on prey. If you are a snowshoe hare, something a fox likes to eat, camouflage helps you avoid notice.
Here are some of the ways predators and prey disguise themselves:
Mother grouse thought Larson was a predator. When she couldn't distract her, she protected her chicks by telling them to freeze so they would blend into the environment.
They blended in because their coloration matched the colors of their surroundings - dirt, white birch logs, dead leaves, twigs, and weeds - so well. The many colors in their feathers help break up their body shape, Larson says. It's hard to see where the landscape ends and the bird starts.
Sandpipers are well-camouflaged all year long, even though they migrate from Arctic Alaska and Canada to the southernmost tip of South America. When they arrive in the Arctic in the spring, their feathers are speckled with white, brown, and black. That way, they can build their nests in the lichens and other plants of the tundra floor without being seen.
"They are amazing interior decorators," says Heather Johnson, a specialist at the United States Fish and Wildlife Service's National Conservation Training Center in Shepherdstown, W.Va. "They have no mirror to tell them what they look like," she says, "yet they instinctively nest and live in areas that match their feathers and coloring."
Their eggs, flecked with black and brown, also match their surroundings. "This is important," Ms. Johnson says, "because they don't build an actual nest. Instead, they make a little scrape in the tundra and lay their eggs on the ground." The chicks, born fully feathered, also blend in. "You can be standing right on top of them and you won't see them until they move," she says.
You probably already know about how chameleons change color depending on their surroundings. Snowshoe hares and Arctic foxes change from brown in summer to white in winter, to blend with the snow.
But birds change colors, too. The willow ptarmigan, an Arctic bird, lives all its life on the tundra in Canada and Alaska. "In the winter, they are as white as the snow and ice around them," Johnson says. But as the snow melts, they molt. Their white feathers slowly fall out and tan ones grow in, allowing them to feed and nest unseen among the bushes. As winter approaches, white feathers replace the tan ones.
When fish change color to match their background it's called "cryptic coloration." The flounder is king of this process. It changes color to match the bottom, where it rests.
Many fish and marine mammals (porpoises, for instance) are two-toned. This is a form of camouflage called "counter shading."
"If you see a flat fish, like a halibut, they are white on the underside and dark on top," Johnson says. That way, if you're an underwater predator looking up toward the surface, the fish's belly blends in with the light streaming down from above. If you are a predator looking down on the halibut, the fish disappears into the bottom of the ocean.
Some sea birds have a similar coloring. The thick-billed murre has black feathers on its back and a white front. "They look like a little penguin," Johnson says. Like penguins, they are wonderful swimmers. Murres live 99 percent of their lives on the water. They aren't very graceful on land. Their legs are so far back on their bodies that they can't walk. They come to shore only to nest and breed.
Because they spend so much time in the water, with their white bellies submerged and their black backs exposed, this counter-shading keeps them from being seen.
Their coloring also helps them warm up and cool off, as needed. Black adsorbs heat, and white reflects it. So the birds use their coloring as a way to regulate the temperature of their eggs during incubation. On cool days, the bird turns its back to the sun, to absorb heat to warm the eggs. When the temperature is warm, the bird turns its white chest toward the sun to reflect the heat.
Zebras may not seem very camouflaged, with their black and white stripes against the brown savannah grasslands of Africa. That's because they rely on illusion for their defense.
It doesn't matter what color zebras are, because most zebra predators (lions and others) can't see in color. But lions can see shapes. "The zebra's wild pattern protects the animal by breaking up its body shape," Larson says.
Because zebras are herd animals, they don't need to blend in to their surroundings. They only need to blend in with each other. If they stand still in tall grass, their vertical pattern makes it almost impossible for a predator to distinguish individual animals.
If the herd runs, the predator can't tell the difference between a zebra's head, body, or legs, Larson says. "There is safety in numbers." Only when a zebra becomes separated from the herd is it in trouble. (Might spots on cows be similarly designed to confuse predators?)
Spies love disguises. They allow spies to go anywhere without having to hide. Yet no one knows who they really are.
Animals use disguises, too. Smaller, weaker animals use them to look tough. The copycat animals are called mimics.
Take the coral snake and scarlet snake, for example. The poisonous coral snake doesn't have to be camouflaged. Its red, yellow, and black stripes keep it safe. Bright colors in nature often are a signal that says, "Don't eat me, I taste bad," or "I am poisonous." Other animals know to leave it alone. The scarlet kingsnake is actually harmless. But it looks like the coral snake with red, yellow, and black stripes - but in a slightly different pattern.
Not wanting to take a chance, predators leave them alone as well. (You can know the difference by remembering this rhyme that refers to the order of stripes: "Red on yellow, kill a fellow. Red on black, won't hurt Jack.")
Some animals imitate objects in their environment. The giant swallowtail caterpillar looks almost exactly like a bird dropping. It rests motionless during the day and feeds at night.
The leaf insect looks so much like leaves that sometimes it is bitten by leaf-eating animals! Leaf insects mimic the shape, color, and texture of leaves. These 4-inch-long insects have extremely flattened, irregularly shaped bodies, wings, and legs. Their wings even have veins like leaves do. The insects scatter their eggs on the ground. When they hatch in the spring, the young resemble adults, except that they are reddish in color. As soon as they begin feeding, they change to the color of the leaves they eat.
The leafy sea dragon (a fish) resembles a little dragon with leaves growing out of its body. This close relative of the sea horse looks like a plant so it can hide among floating seaweed or kelp beds off the coast of Australia. Leafy sea dragons feed by sucking up plankton, larval fishes, and shrimplike crustaceans called mysids or sea lice in their small mouths. Their camouflage is so unusual, in fact, that they're attracting unwanted attention. People have captured so many of them to put in aquariums that the Australian government has declared the fish an endangered species. Sadly, much of their habitat has also been destroyed by water pollution.
Sometimes, animals depend on camouflage to capture their prey. The polar bear's diet is almost exclusively seals. Polar-bear fur appears white, which helps them hide on the pack ice of the Arctic and sneak up on seals. Their hair is actually transparent with a hollow core. Polar bears look white because the hairs reflects light from the ice. It's the same reason that snow appears white to us even though it is really made up of water ice. "[Polar bears] are well adapted to their environment because they always live on the ice in a place that is never ice-free," Johnson says.
The five-foot-long angel shark lives in the Pacific Ocean. It looks more like a sting ray than a shark, with its large fins resembling wings. Its coloration (gray with olive blotches) and flat shape help it hide on sandy ocean bottoms. The shark preys on other fish by burying itself in the sand and ambushing them as they swim by. It likes to eat small fish and squid. Though it's not very dangerous to humans, it may bite if surprised or harassed.
Soldiers, spies, hunters, and hide-and-seek players have all learned quite a bit from animal camouflage.
Spies wear black to hide in the shadows. Soldiers and hunters wear clothing decorated with patches of muted greens, browns, and tans and paint their faces so they can hide in forests.
So the next time you take a walk in the woods, think about it: You may be surrounded by animals, birds, and insects and never know it!
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If you want to be the last person found when playing hide and seek, follow the example of well-camouflaged animals. Pay attention to your surroundings!
If you play at night, wear dark colors, keep your hands and face covered if you can, and hide in the shadows.
If you play on a summer's day, wear clothes with muted brown and green colors that match your yard. Avoid bright pinks or purples.
You can even play in the snow if you dress warmly - and bring a white sheet.
Most important, BE STILL. It's harder to see someone who doesn't move.