Blacktail jack rabbit Giant spotted whiptail Curve-billed thrasher Arizona scorpion Roadrunner Coyote

Sonoran area offers two rainy seasons, some 2,000 plants, several climates

Deserts cover about 20 percent of all the land on Earth, and North America has four: Great Basin, Mojave, Chihuahuan and Sonoran.

The Great Basin Desert, which is the farthest north of the four, is the highest in elevation and the coldest. It covers most of Nevada and Utah, and parts of Idaho, Oregon and Arizona.

The Mojave Desert, which is just below the Great Basin Desert, lies mostly in California but stretches into the southern tip of Nevada and a small section of western Arizona near Kingman.

The Chihuahuan Desert stretches north from Mexico into Texas, New Mexico and Arizona.

The Sonoran has more than 2,000 kinds of plants, much more than the other three deserts. Why? There are two main reasons.

First, our desert has two rainy seasons instead of just one. The Great Basin and Mojave deserts get most of their rain in the winter, while the Chihuahuan Desert gets most of its rain in the summer. The Sonoran Desert gets rain in winter and summer, which means more plants can grow.

Second, the winters are a lot milder than in the other deserts, where it snows and gets below freezing more often. Mild winters are easier for plants to survive.

The saguaro, known around the world as a symbol of the American West, shows up in Hollywood movies as if it grew from Montana to Texas. But the truth is, it only grows in Arizona, Sonora and a sliver of California - nowhere else in the world.

Some of the subdivisions of the Sonoran Desert are so green and wet as deserts go that some scientists don't even think they should be considered desert.

These places may be lush and wet by desert standards, but that doesn't mean life is easy for wildlife. Water is scarce, and the hotter it gets, the more water animals need. How do they survive?

The first way animals cope with the hot daytime temperatures is by being nocturnal - active at night - or crepuscular-active at dawn or dusk. Kangaroo rats and ringtails are nocturnal, while bobcats are crepuscular. Javelina do hang out during the day in the winter, but never in the summer.

The second way animals beat the heat is by finding or making their own microclimates, or cooler areas. Animals from cactus wrens to mule deer seek out the shade of a plant or a rocky crevice. Other animals like squirrels dig burrows and come out of them only for an hour or so when they're hunting for food.

Another way for animals to cope with the heat is by changing their wardrobe. Lots of animals like coyotes shed their winter coats in late spring.

Animals also beat the heat by evaporative cooling. Wet your hand and blow on it. Feels cool, right? Animals use the same evaporative process by doing things like panting. An owl flaps the skin under its throat in way that moves air over its mouth, another form of evaporative cooling called gular fluttering.

If you live in an urban part of the Arizona Upland in Tucson and don't see too much wildlife, don't think it's not around. Just ask Barbara Terkanian of the Desert Museum. She'll tell you you're surrounded - by invertebrates, that is. About 95 percent of all the critters in the Sonoran Desert are invertebrates like beetles, flies, ants, spiders and scorpions.

All content copyright 1999, 2000, 2001, 2002 AzStarNet , Arizona Daily Star and its wire services and suppliers and may not be republished without permission. All rights reserved. Any copying, redistribution, or retransmission of any of the contents of this service without the expressed written consent of Arizona Daily Star or AzStarNet is prohibited.