Sierra Nevada Yellow-Legged Frog

Rana sierrae

Picture of Sierra Nevada Yellow-Legged Frog
Photo Credit: Rick Kuyper/USFWS

Sierra Nevada Yellow-legged Frog

Basic Species Information

STATUS

Endangered. This species is in danger of extinction throughout all or a significant portion of its range.

DESCRIPTION

The Sierra Nevada yellow-legged frog is medium size, measuring about 3 to 8 cm (about 1.5 to 3.25 inches) on average. Females tend to be slightly larger than males.

Adult frogs have a mix of brown and yellow coloring on their upper body, but can also be grey, red, or greenish-brown, usually with dark spots or splotches. These spots can look like lichen or moss, to give the frog a camouflaged look. The belly and underside of the back legs, and sometimes all the way up to the front legs, are yellow or light-orange. This gives the frog its name of "yellow-legged."

If disturbed or threatened, these frogs produce a distinctive mink-or garlic-like odor to ward off predators and other animals.

Although these frogs do not have vocal sacks, they can vocalize in or out of water, making what has been described as a flat "clicking" sound.

The Sierra Nevada yellow-legged frog is very similar to the mountain yellow-legged frog. Although they look alike and are found in very similar habitats, they are a genetically different species. The physical difference is that the Sierra Nevada yellow-legged frog has shorter legs, on average.

FOOD SOURCES

This species eats a variety of terrestrial and aquatic invertebrates and tadpoles. It may also consume dead frogs and its own eggs.

Frogs tend to sit and wait until they see prey come within range, then they strike, or creep up a little then strike, using their large sticky tongue to catch the prey and bring it into the mouth.

HABITAT

Typical habitat would include lakes, ponds, marshes, meadows and streams, at high elevations. Sierra Nevada yellow-legged frogs are highly aquatic and adults can be found sitting on rocks along the shoreline, where there was little or no vegetation. They are and rarely found more than a meter (3.3 feet) from water.

This species historically inhabited lakes, ponds, marshes, meadows, and streams at elevations typically ranging from about 1,371 to 36,957 m (about 4,500 to 12,000 feet), but can occur as low as 1,067 m (about 3,500 feet) in the northern portions of their range.

HIBERNATION

This species tends to spend the winter at the bottom of frozen lakes, emerging shortly after snow melts. In years of heavy snow, the frog may only be active for about 3 months.

MATING

Reproduction is aquatic. Mature adults come into breeding condition and the males call to advertise their fitness to competing males and to females. Fertilization is external, with the male grasping the back of the female and releasing sperm as the female lays her eggs.

A cluster of 100 to 350 eggs is laid in shallow water and is left unattached in still waters, but may be attached to vegetation in flowing water. Egg-laying sites must be connected to permanent lakes or ponds that do not freeze to the bottom in winter, because the tadpoles must live in the water over winter.

If a body of water used for breeding dries up for just one season, 3 to 4 generations of tadpoles will be destroyed.

The eggs hatch into tadpoles, which feed in the water and eventually grow four legs, lose their tails and emerge onto land where they disperse into the surrounding territory.

RANGE

These frogs occupy the western Sierra Nevada north of the Monarch Divide (in Fresno County) and the eastern slope of the Sierra Nevada (east of the crest) from Inyo County, through Mono County (including the Glass Mountains), to areas north of Lake Tahoe.

Although the area where the frog is found is close to what it had been historically, there are far fewer frogs found within this area now.

Most of these frogs are now found on National Forest and National Park lands.

PREDATORS

THREATS

Studies show that populations of Sierra Nevada yellow-legged frog have declined by almost 70 percent.

There has been a range-wide reduction in abundance and geographic extent of surviving populations of frogs following decades of fish stocking, habitat fragmentation, and most recently a disease epidemic. Surviving populations are smaller and more isolated, and breeding in disease-infested populations is highly reduced from historic norms.

WHAT YOU CAN DO

Wherever you live in California, there are zoos and nature centers where you can see and learn about frogs.

Need more specifics? Download the Sierra Nevada Yellow-legged Frog scientific species account.