Camouflage is an animal's ability to hide itself from predators and prey. Animals use camouflage to hide from predators that want to eat them or to hide from prey they want to eat. Most animals camouflage themselves through colorization—the color of their skin, fur, feathers, or scales matches their environment, mimics a leaf, stick, or some other thing common in their surroundings, or their color pattern allows them to blend in with other animals in their species to make it difficult for predators to tell them apart.

There are many different types of camouflage, but the main type is called crypsis. It is when an animal's coloring allows it to blend in without being seen. Other types of camouflage include patterns that make an animal's movement difficult to detect or the ability of an animal to mask its smell.

Some animals, like the toad below, try to match their background to avoid being seen. Some animals, like the ptarmigan, even change color entirely with the seasons to blend in to the changes in their environment.

The ghost mantis has a body that looks like a brown leaf. It is an example of an animal that mimics, or copies, something from its environment to avoid being seen.

Want to see how camouflage works? Try this experiment. Here's what you'll need:

3. Mix the the paper squares together and spread them out over the mat of paper.

4. Find a friend and ask him or her to pick up as many pieces of paper as they can in 10 seconds. The only rule is that he or she must only pick up one piece of paper at a time.

5. Once they've finished, count the number of brightly colored squares and the number of printed squares.

If your friend is like most people, he or she will have many more colored squares of paper. Why? Because they are easier to see. This is how camouflage works, too. If an animal blends into its background, it is less likely to be attacked by a predator.

The grass wasn't really (literally) a magic carpet; it wasn't a colorful woven piece of cloth you'd put on your floor. The asparagus wasn't really (literally) an entire forest of trees painted silver. The author, E.B. White, wasn't being literal when he wrote these lines, he was being figurative. He meant that the ice covering the grass made it sparkle and look fancy, like a carpet covering the ground. He meant that the ice covering the asparagus made it shimmer in the light so that it looked silvery and with all the stalks standing up out of the ground, it resembled a tiny forest .

Both of these examples are similes, but there are lots of other types of figurative language.

Idioms are any type of figurative language that is used so often, it becomes commonplace. An example you've probably used yourself is, "killing time." You didn't mean that you grabbed time around the throat and choked it to death, you meant that you did something unimportant while you were waiting. "We killed time until the movie started."

Idioms are often unique to a region or culture. In México, they don't use the phrase "killing time," they instead say, "está picándose los ojos" which means he's "poking his eyes." They don't literally mean he's poking his eyes, of course, just like in the U.S. we don't literally mean we're killing time. It is an idiom that means they are wasting time while waiting for something.

sold them to clothing makers in Europe. The pelts were often used to make the collars of jackets. At the beginning of the 1600s, however, beaver hats became very popular. Hats were big business in those days. Although it seems strange today, for centuries almost all men and women in Europe wore hats, so when beaver hats became popular, millions were sold. Beaver hats kept fashionable ladies and gentlemen dry and warm in the rainy weather of London, Paris and other European cities.

Most beaver pelts for these trendy hats came from Russia, but by the late 1600s, beavers were almost extinct in Russia and Europe due to over-trapping to supply enough beaver pelts for all those hats. No other fur looked as good or withstood the weather as well as beaver, so the abundance of beavers in North America became a valuable resource. That's why by 1670 the French, Dutch and English had each established companies in far-off North America to take advantage of the furs available there. In fact, much of the development of the United States and Canada is thanks to the beaver hat fashion trend. Beaver pelts became big business.

When fur trappers began, many furs were of value, but once the beaver hat craze took hold, beaver pelts became the main trade item. Beaver fur is particularly well suited for making hats and depending on the size and quality of the pelts (and the size and quality of the hat) it would take between one and five pelts to make a hat. Though no data exists that tells us exactly how many beaver hats were made, we do know that 500,000 hats were exported from England to Europe in 1760 and that doesn't take into account how many beaver hats stayed in England (Net, 2009). Since the popularity of beaver hats lasted for more than 100 years, it's safe to assume tens of  millions of beavers were killed.

all, in the use of silk in the manufacture of hats, which has in a great measure superceded [sic] that of beaver. The curse of the trapper is leveled against all the new-fashioned materials of Paris hats" (Ruxton, 1924, p.146).

The demand for furs meant an invasion of people—people to trap the animals and skin them, people to trade those furs with, people to supply the things trappers and traders needed like clothing, traps and food. To supply this, forts were established along the major North American rivers which meant Europeans began living there permanently. With the establishment of  Jamestown in 1607, Québec in Canada in 1608 and Plymouth in 1620 and forts popping up in the interior of the country to supply the trappers and traders, more and more people were coming to North America to stay. This meant the Native People's way of life was forced to change.

The decline in beaver hat popularity didn't mean Europeans would leave North America or that things would go back to "normal" for the Native Americans. Their way of life and the environment they lived in had been permanently changed. Though they thrived for thousands of years in North America, for several generations Native People had given up hunting for their own food and clothing in order to trap beavers. They therefore depended on the forts and trading posts for much of their food and clothing just as the Europeans did. Old ways of living that had been handed down for centuries frequently became lost and often didn't matter anyway since their land was now occupied by settlers and often times the animals they relied upon were driven away or over-hunted.

 continued to trade themselves. They would sometimes fight with other Native American groups for access to beaver-rich areas and some gave up their traditional ways of living and spent their time hunting beaver instead.

Louis and Clark explored the Northwest Territory in 1805-1806 and this opened up the western part of the continent to even more trapping and expansion. "Mountain men" such as Jim Bridger, Kit Carson, and Jedidiah Smith traveled throughout the west and trapped in the Rocky Mountains in the early part of the 1800s.

Early explorers thought they would find gold and silver on the eastern coast of what is now the United States, much like the conquistadors had in Mexico and South America. Instead, the treasure they found was a furry rodent that led to the establishment of forts and the creation of very successful companies that drove the economy and contributed to the expansion of settlements farther into the North American continent. Native people were often killed, especially if they tried to fight for their lands. As much as 90% of the Native American population was killed by disease or war. The structure and lifestyle of the Native People who had lived in North America for thousands of years would never be the same.

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