The Sonoran Desert



The Sonoran Desert in the United States of America reaches from extreme southeastern California across the western two-thirds of southern Arizona. In Mexico, the desert stretches south to encompass much of the state of Sonora, as well as the eastern shore of Baja California to the town of Loreto. Most of the ecosystem is very arid (dry), with an average rainfall of just 3.5 inches.  Temperatures range from over 140F in the summer to nearly freezing during the winter nights. 


Vegetation in the desert ranges from small shrubs like creosote and white bursage, and grasses, as well as taller trees with small leaves to minimize water loss, such as the palo verde, mesquite, and ironwood.  The desert is also home to a huge variety of cacti, such different species of the saguaro (endemic to this desert), prickly pear, barrel, organ pipe, and others.  The vegetation in the desert is extremely well adapted to surviving in a land of very hot sun and little water.  For example, saguaros (pronounced suh-whah-roes) can live for up to 200 years and mature saguaro can be 50 feet tall, sport as many as 40 arms, and weigh as much as seven tons when full of water. With roots that stretch out for up to 50 feet around, saguaros are very efficient at absorbing water and can survive for two years on the water from one good rainstorm.  Over all, there are more than 560 different plant species, which makes the Sonoran desert the most diverse in the world in terms of vegetative growth.


Wildlife species in the desert include Sonoran pronghorn antelopes, desert bighorn sheep, and Bailey's pocket mouse, all of whom use ironwood, cacti species and other vegetation as both shelters from the harsh climate and a water source.  Other mammals include predators like mountain lions and coyotes, as well as their prey: black-tailed jackrabbits and round-tailed ground squirrels. 


Among the bird species found in the Sonoran desert are the sanguaro-inhabiting cactus wren, black-tailed gnatcatcher, phainopepla, Gila woodpecker, and Costa's hummingbird. Perhaps the most well-known Sonoran bird is the roadrunner, who prefers running over flying as it hunts scorpions, tarantulas, rattlesnakes, lizards, and other small animals.


Of course, no desert is complete without its reptiles.  Fifty-eight species of reptiles, including six species of rattlesnake, are found in the U.S. portion of this rich desert.  Notable lizards include the giant Gila monster and the tiger salamander, which is able to survive in the Sonoran by burrowing underground during the dry season and emerging during wet times.


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Tiger salamander, saguaro cactus, roadrunner, mountain lion,