How well do you know America's deserts?
The United States has four major deserts, each with its own climate and wildlife. Six questions, from easy to hard, with explanations.
Did you know?
- The Great Basin gets its name because its rivers and streams never reach the ocean. Water drains into inland valleys, where it forms lakes such as the Great Salt Lake or simply evaporates.
- A ring of creosote bushes in the Mojave Desert, nicknamed King Clone, is estimated to be about 11,700 years old. The plant grows outward from its center as a clone, with the oldest stems dying off in the middle.
- Kangaroo rats in US deserts can live their whole lives without drinking water. They get the water they need from the seeds they eat and have kidneys that are extremely efficient at conserving water.
Four deserts, four personalities
Deserts cover much of the American Southwest and Great Basin. Scientists usually define a desert as a place that gets less than about 10 inches (25 cm) of precipitation a year, or where more water evaporates than falls. The four major US deserts — Great Basin, Mojave, Sonoran and Chihuahuan — differ greatly in temperature, rainfall and the life they support.
Why deserts form here
Many US deserts lie in rain shadows. As moist Pacific air rises over the Sierra Nevada and Cascade Mountains, it cools and drops rain and snow on the western slopes. By the time the air descends on the other side, it is dry and warm.
Hot and cold deserts
The Mojave, Sonoran and Chihuahuan are hot deserts, while the Great Basin is a cold desert with freezing winters. Even hot deserts can be surprisingly cold at night because dry air and clear skies let heat escape quickly.
The Chihuahuan Desert
The Chihuahuan is the largest desert in North America, though most of it lies in Mexico. In the US it covers parts of Texas and New Mexico, including Big Bend National Park, and it is known for yuccas, agaves and many kinds of cacti.
How plants survive
Desert plants use clever strategies. Cacti store water in thick stems, many shrubs have small leaves to reduce water loss, and some wildflowers stay as seeds for years, sprouting only after heavy rain.
How animals cope
Many desert animals are active at night, when temperatures fall. Some rarely need to drink at all, getting water from their food, and others escape the heat in burrows, where the ground stays cooler and more humid.
Fragile desert soils
Much of the desert floor is covered by a living crust of bacteria, lichens and mosses called biological soil crust. It holds soil in place and adds nutrients, but a single footstep can crush it, and recovery may take decades.