History of Deserts
A desert is an area of land with little precipitation and wildlife (due to hostile conditions). While normally, people assume all deserts are hot, there are cold deserts also (Note that the definition doesn't include temperature). Deserts are created when there is little vegetation, and the soil is exposed to the elements, making it infertile, which is why not much wildlife can be sustained. Deserts cover about 1/3 of the world's land, including the west coast deserts of the U.S., the cold deserts of Antarctica and the Arctic regions, the mid-African deserts, and the Asian deserts, including the Gobi and Taklamakan deserts in China.
Wildlife living in the deserts have to adapt differently than the wildlife in other biomes. The flora has to have water-resistant cuticles and physical features to deter herbivorous fauna. The fauna have to keep warm/cold in cold/hot deserts respectively, they have to be able to find food and water, and they have to avoid prey. In hot deserts, many animals are nocturnal, sleeping during the hot day and waking up at night in the cool shade to nourish themselves. In the cold deserts, many animals, such as bears, go into a state of dormancy (hibernation) in the cold seasons to conserve energy, nourishing themselves so that they can stay alive during the long winter.
Although it seems that the desert is always an inhabitable place to live and sustain, there are some places in the deserts that are suitable for human needs. Sometimes, in hot deserts, when all of the sand is blown away, bedrock is exposed, making what is called a desert pavement, where little erosion takes place. Also, temporary lakes may form from the little precipitation that these deserts get. When these evaporate or soak into the earth, salt is left over, an important staple. When water is collected underground, oases may occur. An oasis is a body of water in a desert that sustains plant and animal life. Human settlements develop around these oases.
People have had a hard time living in deserts since the start of settlement. The harsh conditions make it hard to grow crops and raise livestock. For this reason, almost all of the desert settlers are nomads. Nomads travel around with their livestock, mainly camels, which have thick eyelids to keep out the sun and sand, hooves to keep from sinking into the sand, and the ability to stay hydrated for very long periods of time, and trading goods, to travel to different oases where they can trade their goods and rest for a long journey ahead.
Deserts in North America/Geography
Deserts in North America are primarily found in the western and southern parts of the continent. Examples include the Chihuahuan Desert in Texas and Mexico and the Mojave Desert in southern California and Nevada. The largest desert in North America, the Great Basin Desert, is located in northern Nevada and Utah, while the Sonoran desert is located in Mexico and Arizona. While some ecologists claim that the Okanagan region around Osoyoos Lake in western Canada is a desert, most agree that it is actually a semi-arid steppe.
Climate of Deserts
Deserts are generally classified as areas that receive less than 10 inches (~25 cm) of rain every year, though some ecologists prefer to use the aridity index in classification. Most deserts in North America have very hot climates, although deserts in other areas, such as Antarctica and Mongolia, can be very cold. In fact, the hottest recorded temperature in the world (54 degrees Celsius) comes from Death Valley, California (tied with Mitribah, Kuwait), part of the Mojave Desert.
Because of the extreme temperatures and low precipitation of deserts, vegetation is often very sparse. The plants that do exist often have adaptations that help them conserve water, such as waxy coatings that minimize transpiration. Animal life is also limited, but some reptiles, mammals, and arthropods manage to survive.