The 100-Mile Circle

Tucson and its surrounding environs have long been a Mecca of sorts for herpetologists. The reason for this is the density and diversity of the amphibian and reptile populations found here. The Sonoran Desert Region provides an array of habitat niches, and reptiles and amphibians have evolved and adapted to fill them. The mountain ranges, which are forested islands in that desert, have allowed still other forms to evolve in isolation from each other. This page is an illustrated checklist of the species of reptiles and amphibians found within “the 100-Mile Circle” – an arbitrarily chosen area radiating 100 miles in all directions from the center of Tucson.

The 100-Mile Circle consists of three sections. The first is a brief overview of the location and physical attributes of the Circle. The second is an exploration and detailed description of each biotic community in the Circle. The third section lists, describes, and illustrates the reptiles and amphibians that live there.

Note: All images in the 100-Mile Circle and elsewhere on this website are copyrighted.  Any copying, use, or reproduction of these images without the expressed permission of the photographer is a violation of copyright law.


The Location

View the map that outlines the area within the 100-Mile Circle. Habitats produced by the topographical mixture in this area are highly variable and are affected by diverse conditions of elevation, topography, geology, climate and more.

See the Location


Biotic Communities

The 100-Mile Circle is remarkably diverse in terms of habitats and vegetation. This section lists and describes the biotic communities within the Circle.

Learn More


The Inhabitants

This section is a portal to an illustrated checklist and species accounts of the 108 reptile and 26 amphibian species that occur within the 100-Mile Circle.  The scientific and common named used herein generally follow Crother (editor, 2012), Society for the Study of Amphibians and Reptiles, Herpetological Circular 39 (for species that occur in the US) and Liner and Casas-Andreu (2008), SSAR Herpetological Circular 38 (for species that occur exclusively south of the border), unless recent publications indicate another name is more appropriate. Higher taxonomy follows the and Amphibiaweb.

The 100-Mile Circle is a work in progress and will not be completed without help from volunteers.  About a fifth of the 134 species in the Circle lack species accounts, and we are in need of images portraying some pattern variants, as well as various behaviors.  We invite you to help us fill in the gaps.  In particular we are looking for volunteers to help us complete species accounts, which currently take two forms. The first is a detailed and thorough treatment, which ultimately we would like to have for all species. These are published in the Sonoran Herpetologist and then posted here. Dr. Robert Bezy has set the standard for these, such as his treatments of the Western Banded Gecko, the Elegant Earless Lizard, and the Zebra-tailed Lizard, although other authors have also produced excellent, detailed accounts. The second type of account is a placeholder treatment that briefly describes a species and its natural history. These will remain in place until more detailed accounts can be prepared.  We encourage you to contribute either type of account, as well as photographs that help illustrate the herpetofauna of the Circle. Contact Jim Rorabaugh ( regarding photos and account format and minimum content.

See the Inhabitants


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