My dictionary defines reptiles as a "class of air-breathing, cold-blooded vertebrates, including snakes, crocodiles, lizards, and turtles, having skeletons and usually covered with horny plates are scales." Of course, we don't have any crocodiles (or alligators) on the desert, but we do have the others. There is amphibians include frogs and toads, and we have some of those, chiefly near pools of water. There is also some fish species. All are cold-blooded, relying on their environment (chiefly air temperature and sunlight) to regulate their body temperature. Mammals generate their own body heat through their metabolism.

Several snakes are native to the Mojave Desert. Most are not dangerous to mankind or their pets, unless the pets are runaway mice, lizards, or birds. Most are not poisonous. Several, like the red racer (a protected species), hog-nosed snake, king snake, and gopher snake benefit from being civilization-followers, and even make docile pets. Snakes eat insects, mice, lizards, eggs, fish (if they can capture them), small birds, and even other, smaller snakes.

More dangerous are the rattlesnakes, including the western diamond-back, sidewinder, and our infamous Mojave green. Most snakes are secretive or reclusive and would rather hide from mankind than risk the encounter. Some of the rattlers and the Mojave green are more aggressive. If cornered, they will bite. If you're walking on the desert or adjacent areas, walk noisily and put your feet down with a clump. Any nearby snakes (and most other wildlife) will flee or hide to avoid you. Rattlers sound a warning before striking. Most snakes are born alive, not hatched from eggs. The poisonous ones are dangerous from day one.

It is unlikely you'll ever see a Gila monster in the wild, but they are the only poisonous lizard in the U.S. You probably won't encounter any geckos or chuckwallas, either. Most lizards you might see are "whiptail" lizards, whose tails detach when caught, and re-grow. Horned toads used to be common, but I don't see them anymore. Lizards eat insects and grubs, and lay eggs.

Lastly, is the endangered desert tortoise. Tortoises used to be quite common, but they avoid distrbances and have retreated or been driven to only lonely parts of the desert. They can live a long time, perhaps twenty or thirty years. They get most of their moisture from plants and even store it beneath their shell. If encountered, leave them alone. They belong here and we don't.

Toad and frogs mostly live around ponds, lakes and irrigated areas. Some even hibernate beneath the ground during hot or cold spells and emerge when condtions improve. Like rabbits, they might even take up residence in your garden. They are mostly hamless and eat insects and grubs.

The desert has few fish, for they need open water. The various lakes are stocked and usually open to fishing - chiefly trout, bass and catfish. But, except for a species in Death Valley, none are native to the Mojave Desert.

I hope you've enjoyed our exploration of desert natural history. Suggestions and comments are welcome. I'll be continuing a version of natural history in 2009, including mountains, climate and weather. In January 2009 we'll discuss earthquakes. Enjoy the rest of 2008, the coming holiday season, and Christmas. I'll be back next year.

Watch Richard Doornbos sing a portion of "The 12 Days of Christmas" on