Southwestern Center for Herpetological Research - Conservation - Preservation - Education - Public Information - Research - Field Studies - Captive Propagation - Advancing knowledge and understanding of the herpetofauna of the American Southwest


As most of the material contained in this web site deals with the various species of reptiles, turtles, crocodilians, and amphibians native to the Southwestern United States or as it is frequently called the American Southwest, we should define what constitutes the American Southwest.

Definations of this region of the United States vary greatly from source to source depending on whom you are talking to. About the only thing that that you can expect to get an unanimous agreement on is that the states of Arizona and New Mexico make up at least part of this region. Beyond those two states, the boundaries of the American Southwest become somewhat hazy. Most people from the Eastern United States consider Texas and Oklahoma to be a part of the American Southwest, while many of those living in California and Arizona consider Texas to be part of the Deep South. Some scholars consider California, Nevada, Utah, Arizona, New Mexico, Colorado, Texas and Oklahoma to all be Southwestern states.

For our purposes here at the Southwestern Center for Herpetological Research (SWCHR), we define the American Southwest as being only the states of Arizona, California, New Mexico, Nevada, Texas and Utah. While we do recognize that certain parts of California, Nevada, Texas, and Utah do not contain the geologic and other natural features that are generally associated with the American Southwest, we have opted to include those states in their entirety for the sake of having a more easily defined border for the region.

Map of the American Southwest

The Earth is divided into physiographic provinces or regions which are broad-scale subdivisions based on terrain texture, rock type, and geologic structure and history. Ten different major physiographic provinces exist within the six states that we have designated as being part of the American Southwest. Those ten major physiographic provinces are the Great Plains, Coastal Plain, Central Lowland, Southern Rocky Mountains, Middle Rocky Mountains, Colorado Plateaus, Basin and Range, Cascade-Sierra Mountains, Pacific Border, and Lower California. (U. S Dept. of the Interior, U.S. Geological Survey). It is also worth noting that four deserts (Mohave, Sonoran, Great Basin, and Chihuahuan) are found within the boundaries of these six states and that four of the states border Mexico to the south.

| Home | The American Southwest Defined | Snakes of the American Southwest | Lizards of the American Southwest |
| Turtles of the American Southwest | Crocodilians of the American Southwest | Amphibians of the American Southwest |
| Discussion Forums | Join SWCHR Today | Photo of the Month Archives (2007-2015) | Awards for Photographic Excellence |
| Herpetological Papers & Articles | Protected Species | Herpetological Dictionary | Southwestern Weather |
| SWCHR Bulletin Back Issues | SWCHR Position Papers | SWCHR Herper Surveys | Recommended Herpetological Links |
| Webmasters - Link to SWCHR | SWCHR Corporate Sponsorship | Contact Us |

Advancing knowledge and understanding of the herpetofauna of the American Southwest

© 2007 - 2016 Southwestern Center for Herpetological Research

Powered by
All photographic images and articles used on this site are used with permission of the respective photographer or author and are protected by copyright. Unauthorized use is prohibited without written consent of the individual photographer or author.