Amphibians - Yosemite National Park (U.S. National Park Service) Pacific Tree Frog. Sierra newt can be seen most often between November and May when migrating to breeding sites. Ben Lehman. Eleven native and one-non-native amphibian species can be found in Yosemite. Three of these species—the Sierra Nevada yellow-legged frog, the Yosemite toad, and the Mount Lyell Salamander—are only found in the Sierra Nevada of California. One species, the foothill yellow-legged frog, has not been documented in the park in many years. This species, however, was recently documented just outside the park in the Tuolumne River. Park scientists are surveying the river inside the park in the hopes of locating some individuals. The Sierra newt spends most of the year on land. It retreats to moist natural and human-made refuges, such as rodent burrows, seepages, rock fissures, mine shafts, and rotten logs during the dry season. Moisture that comes with the first falls rains brings this species out to breed. Newts are most visible between November and May when they are migrating to and from their breeding sites in nearby ponds, streams, and rivers. During this time, park visitors may see the newts crossing roads or trails. While at their breeding sites, adult males develop a smooth skin and a flattened tail. This allows them to thrive in the aquatic environment. The rest of the year, their skin is thick, rough, and relatively unvascularized to reduce the amount of water lost to evaporation while living on land.
Pacific Tree Frog. Sierra newt|Sierra Nevada yellow-legged frog,|Yosemite toad,|Mount Lyell Salamander—are
Pacific Tree Frog. Sierra newt|Sierra Nevada yellow-legged frog,|Yosemite toad,|Mount Lyell Salamander—are