The California slender salamander (Batrachoseps attenuatus) is a lungless salamander that is found primarily in coastal mountain areas of Northern California, United States as well as in a limited part of the western foothills of the Sierra Nevada, California, in patches of the northern Central Valley of California, and in extreme southwestern Oregon. What makes this amphibian notable is that this species resides primarily in a limited range within California as one of a handful quasi-endemic amphibians in the state. In 2001, it was reported that, on behalf of the National Park Service, Professor David Wake and his graduate students found that the California slender salamander, the most common salamander in California, was in fact twenty separate species spread out along the coast from Oregon to Mexico. Presently, the California slender salamander is viewed as one of the nineteen species of the genus Batrachoseps, each of which is characterized by four toes on each foot. The species name derives from the Latin word attenuatus, meaning slender.