Biology and Conservation of North American Tortoises

Preface

WHy a Book aBout toRtoisEs? Tortoises hold a special place in the minds of most persons. They are symbols of many things, including longevity—much to their detriment, sometimes—wisdom, and cunning. We have been fascinated by their slow, plodding ability to outwit mammals with hyperactivity disorders for centuries. Unfortunately , tortoises also represent a free lunch, or a roadside souvenir, or an annoying impediment to development for some persons. For these reasons and others, tortoises, which have proliferated over the past 50 million years or so, are now under serious threat of extinction. Although saving tortoises, other turtles, or any group of organisms ultimately will require the social will to do so, scientists are the persons who can provide the means. It is important, therefore, for scientists to take stock from time to time of what is known and what is not known about a group of organisms; and that is what this book does for the North American tortoises. We have brought together a distinguished group of tortoise researchers to take stock, and these researchers have responded impressively to the call. The book was originally envisioned as a compendium and comparison of knowledge about two particular species of North American tortoise, Gopherus (Xerobates) agassizii (desert tortoise) and G. polyphemus (gopher tortoise), for which a wealth of information is available. Readers will no doubt see the difference between what we know about these two species of North American tortoises and the other species. Nevertheless , readers will find plenty of information, analysis, and interpretation concerning all of the species within the 18 chapters . The book provides one of the largest literature databases on North American tortoises currently available. We think that the book will serve well as a textbook; a field manual; a source of information for government agencies, nonprofits, and other organizations working with North American tortoises ; a valuable resource for turtle biologists and hobbyists; and a good read for anyone interested in studies of the natural world. Clearly, authors were selected based upon experience and reputation in studying North American tortoises. Where feasible, authors who have studied different species were paired to address common topics. Among the authors is an outstanding group of young researchers, on which the future of North American tortoise research and management will depend. We hope the book will inspire other young scientists to study this fascinating group of organisms. What’s in a name? We would have preferred to use common names throughout, for the sake of clarity for those readers not used to dealing with binomial nomenclature. Although a recognized species has only one Latin binomial at any particular time—even Latin binomials may change (chapter 1)—not so for comPREFACE x preface mon names. To introduce an element of consistency to the common names of amphibians and reptiles, several organizations , such as the Center for North American Herpetology and the major herpetological societies (American Society of Ichthyology and Herpetology, Herpetologists’ League, Society for the Study of Amphibians and Reptiles) have created lists of “official” names. When the North American tortoises included four recognized species, little controversy existed concerning the “official” names. These names were Desert Tortoise (for Gopherus agassizii), Texas Tortoise (for G. ber­ landieri), Bolsón Tortoise (for G. flavomarginatus), and Gopher Tortoise (for G. polyphemus). Perhaps the largest dissention was from those individuals who maintained a preference for Berlandier’s Tortoise, rather than Texas Tortoise. According to some herpetologists, the North American tortoises now include five recognized species, although not all herpetologists agree. The splitting of the former “Desert Tortoise” into two species (chapter 3) has emphasized the problem with multiple common names. According to the joint committee of the ASIH/HL/SSAR, the two new species should have the common names Mohave Desert Tortoise (for G. agassizii) and Sonoran Desert Tortoise (for G. morafkai). Several herpetologists have objected to the use of these names. One position among these objectors is a preference for the use of Agassizi’s Desert Tortoise and Morafka’s Desert Tortoise, respectively. A second position is a spelling preference for “Mojave,” as apposed to “Mohave.” Although common names for several other species use “Mohave” (e.g., Mohave Rattlesnake, Mohave Ground Squirrel), the major objection is that this name is not linked to major geographical entities as they are currently recognized. The use of “Mohave” apparently is intended to recognize the Native Americans who inhabited the area, but the name seems to have little historical validity (e.g., Sherer 1967). The authors of the various chapters...