Introduction

Amphibians are cold-blooded vertebrates with moist, scaleless skin. These animals either occur in close association with permanent water or are active only during wet times of the year. There are approximately 3,200 species in the world, and amphibians are present on all continents except Antarctica.

Amphibians are divided into three groups: caecilians, salamanders, and frogs and toads. Caecilians are elongate, "wormlike," burrowing or aquatic forms that lack limbs and functional eyes. The approximately 165 species are restricted to the tropical regions of the world; no species occur in the United States. Most caecilians are less than 2 ft (0.6m) long; however, one species in South America reaches a length of 5 ft (1.5m).

Most salamanders have a lizardlike shape with four legs and a tail. They have smooth, moist skin that lacks scales. In the New World there are three areas with high species diversity. One is the mountainous region of southern Mexico and northern Central America, with some 50 species. Another is the Appalachian Mountains of the eastern United States, with about 45 species. The third region comprises the Pacific states of California, Oregon, and Washington, with about 35 species.

The species that are present in California have two very different developmental patterns. Some breed in water, and the adults return to streams and ponds during the rainy season to lay eggs. Gilled larvae develop in the water and later transform into terrestrial adult salamanders. Other salamanders are completely terrestrial. The eggs are laid on land in moist places. The larval stage takes place in the egg, and small, fully transformed salamanders emerge. All western fully terrestrial salamanders lack lungs, and respiration takes place through the skin.

Three species of salamanders are known to occur in the California portion of the White-Inyo mountains region. The only state with no native salamanders is Nevada. There have been several reports of salamanders in Nevada, but none have been confirmed. Although the species accounts included here for salamanders have been brought up to date, they are probably incomplete and may even be lacking a species. We would appreciate receiving any additional information, such as a new distribution or a salamander that does not fit the descriptions.

The frogs and toads are the largest group of amphibians. Approximately 2,600 species of frogs and toads are known, and they occur on every continent except Antarctica. The greatest species diversity is in the tropics, but frogs and toads are

Map 9.1

Map 9.2

well represented in temperate regions. These amphibians occur in a great variety of habitats. Some species occur in arid regions, where they spend most of their lives underground, coming to the surface only during occasional rains. Others are fully aquatic and never leave the water. A few species in tropical regions spend their entire lives in the tree canopy. There are 23 families of frogs and toads worldwide, of which 5 occur in California and Nevada. The families that occur in the area under study are the True Toads (Family Bufonidae), Treefrogs (Hylidae), Spadefoot Toads (Pelobatidae), and True Frogs (Ranidae).