Deserts, like seas, forests and grasslands, occur all around the world. There are two kinds of deserts, cold and hot. Both kinds receive very little rainfall and both get very cold at night, but hot deserts bake during the day. The vegetation typically is ground cover, stunted shrubs, or periodical trees and is specially adapted for life in such difficult circumstances. They receive less than 25 cm of rainfall each year and rainfall is very scarce. Some parts of the Sahara Desert can go years without any rain at all.
Deserts experience a wide range of temperature from day to night. There is little to absorb the sun’s radiation, so, it all goes to the soil or sand. Similarly, there is nothing cloud cover, vegetation or water to hold the warmth, so it quickly vanishes away. The sand is very dry and is low in organic nutrients, as few plants live, die and decay there.
Yet … ‘Life’ hasn’t dried out
Desert plants and animals are living in oppressive environments. Although in most ecosystems plants compete for sunlight, here most plants are adapted to minimize the effects of too much solar energy. Deserts wild life revolves around its green habitats mostly. Birds like birds cactus wrens, greater roadrunners, vultures, ostriches and mammals like caracals, black-tailed jackrabbits, fennec foxes, kangaroo rats, meerkats, pronghorns and spotted hyenas are dominating the desert ecosystem. Others like reptiles, arthropods and even highly adapted desert toads also play a major role within the flow of its food web.
Many animals feed on plants, but desert plants give up the fruit of their production very unwillingly. Sharp spines and narrow leaves discourage plant-eaters. The kangaroo rat avoids these obstacles by eating seeds which are safe to eat, but can be hard to find. Many are small and look like grains of sand. With sensitive front paws a kangaroo rat sifts sand to find seeds by touch. Desert animals prevent water leaving their bodies in a number of different ways. Some, like kangaroo rats and lizards, live in burrows which do not get too hot or too cold and have more humid air inside. These animals stay in their burrows during the hot days and emerge at night to feed. Other animals have bodies designed to save water. Scorpions, snakes and spiders have a thick outer covering which reduces moisture loss.
Desert sidewinder ensures that only two points of its body is touching the hot ground at any given time by side-winding, avoiding the serpent movements. The fennec fox has large ears which severe as dual purpose. They are great for listening for insects to eat that may be moving around underground, but they are also loaded with blood vessels, allowing the animals to dissipate excess body heat. Also, the fox’s thick fur coat acts as insulation during cold desert nights. No discussion of desert survival is complete without mentioning the famous camel. Its hump stores fat, which can be used as both a food and water source for the animal when the going gets tough. They also have thick hairs in their ears for keeping out sand, and the same can be said of their eyelashes.
Camels also have closable nostrils, a nictitating eye membrane, and wide feet that act like snowshoes in the sand. Other than that, in their propagation most desert animals and plants are adapted to reproduce quickly during the brief moist period. However, the rise of global temperatures could make deserts an even more uncomfortable place to live than they are now. Precipitation will become even scarcer.
Did you know?
• There are a number of different definitions to describe a desert, but they are typically areas that receive extremely low amounts of rain.
• Deserts generally receive less than 40cm (16in) of rain a year.
• Around one third of the Earth’s surface is covered in deserts.
• The original meaning of the word desert is ‘an abandoned place’.
• Many of the ice free regions of the Arctic and Antarctic are known as polar deserts.
• Only 20 percent of the deserts on the Earth are covered in sand.
• Areas covered in ice or snow can sometimes be called ‘cold deserts’, compared to ‘hot deserts’ in warmer areas.
• The largest cold desert on the Earth is Antarctica.
• The largest hot desert on the Earth is Sahara.
• The Sahara Desert is located in northern Africa, spanning 12 different countries.
• The Arabian Desert in the Middle East is the second largest hot desert on the Earth, but is substantially smaller than Sahara.
• Other large deserts include the Gobi Desert in Asia, the Kalahari Desert in Africa, the Patagonian Desert in South America, the Great Victoria Desert in Australia, the Syrian Desert in the Middle East and the Great Basin Desert in North America.
• The Gobi Desert is located in the north of China and the south of Mongolia. It is growing at a fast rate due to desertification, a process that turns fertile lands into desert areas. It is caused by humans cutting down forests, droughts, climate change and other environmental factors.
• Located in South America, the Atacama Desert is the driest place in the world.
• Hot deserts usually feature high temperatures in the daytime and cold temperatures at night.
• Deserts have very low humidity.