What is the climate like in the desert? What kinds of life can you find there? How do they handle the conditions in the desert?
Deserts are characterized by very low rainfall, usually less than 10 inches (25 cm) per year. Because there is very little vegetation or moisture in the air to retain heat, the hot days deserts are best known for are usually followed by very cold nights. Taken together, the extreme temperature fluctuations and lack of water make the desert environment a very harsh one in which to live. The plants and animals you will find there have a wide variety of adaptations that allow them to cope with desert conditions.
Because food and water are relatively scarce, desert animals have evolved habits that require very little energy and waste little water. For example, snakes, scorpions, and lizards that rely on hunting other animals for food are equipped with highly toxic venoms to kill their prey--this saves the hunter energy that would otherwise be needed to chase, catch, and fight its prey to the death.
To help conserve water that could be lost during the hot days, many desert animals are "nocturnal", meaning they are active only at night. These animals sleep during the day in cool underground burrows or in caves and come out at night to find food. Many animals also have protective coverings to keep them from drying out, like the scaly skins of snakes and lizards, and the hard outer coverings of insects.
Plants also need to save valuable water. Plants known as "ephemerals" have very short life cycles. They can sprout from seed, grow, produce flowers, and make seeds for the next generation in only 2-4 weeks! Their rapid growth allows them to take advantage of the desert's short rainy season which may last only a few days to a few weeks. The newly formed seeds have special waterproof coverings that prevent them from drying out. They will simply wait until the next year's rainy season to sprout and start the cycle over again.
Longer-lived plants, like the big saguaro cactus pictured here, store water
inside their stems. Tough outer coverings help prevent evaporation and
protective spines and thorns keep animals from stealing the water
they store inside.
Submitted by David (England)
(February 10, 1998)