Introduction

Covering 193,080 kmē, the Sonoran Desert is one of the largest North American deserts, as well as being the hottest. Stretching from South-Western Arizona and South-Eastern California, down through most of Baja California and the West of Sonora in Mexico, there is a noticeable difference in climate through various areas. Subdivisions of the Sonoran are often known by other names, such as the Colorado and Yuma Deserts.

Physical Information

The Sonoran Desert is largely comprised of smooth-floored desert basins, seperated by North-West to South-East running mountain ranges. The North-East Sonoran is low and dry, with elevations as low as 43 m at Yuma, to Mount Graham at 3,267 m. Throughout the rest of the Sonoran elevations vary in the range of 150 to 1,500 m, though some mountains rear their heads above 3,400 m. Generally, the elevations in the East are higher than those in the West.

Animal Life

Although a desert, and having the appearance of inhospitible wasteland in places, the Sonoran is a far cry from being devoid of life. Through the mesquite bushes travels a small herd of peccary, while a mule deer makes a meal of cacti fruit in winter, prefering the higher scrub during the hot summer months. Kangaroo rats build complex networks of tunnels beneath the sand, making sure to avoid any of the poisonous snakes prevalent in dark burrows - one of the 11 rattlesnake species, or even a coral snake. The cotton-tail rabbit is found at all altitudes, and, like all rabbits, procreates like wildfire to replace any that have the misfortune of being the previous meal of a snake, or even a rare Gila monster.

Paw-in-feather with the diversity of land animals is the variety of bird life. Many are year-round residents, though a great many species pass over on their way to or from Central or South America from or to Northern US or Canada. The cactus wren is one of the more common, and is in fact Arizona's state bird. The infamous roadrunner is more often seen to the North-East, but can often be sighted in the Sonoran. The red-tailed and Cooper's hawks join the hunt for Kangaroo rats or cotton-tails, as do Kestrels and Falcons. Black vultures, the clean-up crew of the desert, glide over the desert in the constant search for food fit for a scavenger.

Plant Life

Some parts in California have been irrigated to create fertile agricultural areas, while other areas rely solely on rainfall to produce plant-life. Well-developed Desert Ironwoods, Catclaw, and Saguaro are often found on the well-drained desert ranges, while Arizona Ash and Black Walnut, Fremont Cottonwood and varieties of willow flourish in the alkaline soils of stream-banks. Creosote Bush and bursage communities literally stretch for miles on coarser plains, or dense woodlands of Honey or Velvet Mesquite may be found if the water table is high.

The Western reaches, often known as the Colorado Desert, is subject to severe Pacific storms and is therefore noted for ephemeral flowerings in cases of winter-spring rainfall. However, this area lacks summer-rainfall dependant plants such as the Saguaro.

Saguaro

The Saguaro cactus (Carnegiea gigantea) is the largest cactus in the world, and is native and exclusive to the Sonoran desert, primarily in the Northern Saguaro National Monument. They can grow to a colossal 8 metres, and live as long or longer than 85 years. Veritable forests of Saguaro carpet the greatest moisture yielding patches of desert; as each cacti requires decidedly little water to survive and grow, a great many can easily be sustained over even a small area.

Approximate development of a Saguaro
(varies according to moisture availability)
A venerable Saguaro specimen; most likely in it's 90s
Age Height Development
10 years4 cm 
14 years15 cm 
35-40 years1.8-2.5 mStarts flowering
50 years4 m 
65 years6 mDevelops first arm
85 years +7-8 mMature, branched adult