A Guide to the Amphibians
and Reptiles of California

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Identifying Red-legged and Yellow-legged Frogs in California

California Frogs and Toads:

After you have determined that the frog you want to identify is a Red- or Yellow-legged Frog the following information can help you determine which kind it is. (Go to the Frog Identification Key if you haven't yet figured out if it is a Red- or Yellow-legged Frog. Be aware that juvenile American Bullfrogs can look similar to red or yellow-legged frogs. American Bullfrog is shown at the bottom for comparison.)
Red-legged Frogs are found primarily along the coast, and are more common north of the San Francisco Bay due to more destruction of their former habitat south of there. The Foothill Yellow-legged frog occurs with Red-legged Frogs along the north coast, and the central coast. Red-legged frogs have disappeared from the Sierra Nevada foothills and most of Southern California, while the Yellow-legged Frog still occurs in some streams in the Sierra Nevada foothills, especially in the north. The Foothill Yellow-legged Frog is no longer found in Southern California, but the Mountain Yellow-legged Frog can still be found in a few small locations in the mountains. Efforts have been made to stock locations with tadpoles to support populations of frogs.
Visible Differences
Red-legged frogs Red coloring on the undersides of the legs Prominent dorsolateral folds (folds along the side of the body) A dark mask through the eyes Larger - growing up to 5 inches in length (snout to vent)
Yellow-legged frogs Indistinct dorsolateral folds along the sides of the body No dark mask through the eyes. Smaller - growing up to 3.5 inches in length (snout to vent)
As an defensive escape tactic Foothill Yellow-legged Frogs often jump in water and sit on the bottom, relying on their cryptic pattern to hide them in the clear shallow water of a stream, while Other species tend to either hop away quickly, or dive into deep water to hide or swim away quickly.
*Comparison of Rana boylii* - Foothill Yellow-legged Frog with Rana aurora - Northern Red-legged Frog**

Adult Rana aurora - Northern Red-legged Frog - on the left of each picture. Adult Rana boylii - Foothill Yellow-legged Frog - on the right of each picture. Both frogs were found near each other in the same river in Linn County, Oregon.

Red-legged Frogs - 2 Species
There are two very similar species of Red-legged Frogs found in California that meet north of Pt. Arena in Mencocino County. The Northern Red-legged Frog is north of there and the California Red-legged Frog is found to the south. You can identify the species by looking at the range map.
Northern Red-legged Frog - Rana aurora




	Underside of legs is reddish	Range: Red and Purple

California Red-legged Frog - Rana draytonii



The back is sometimes reddish	Underside of legs is reddish	Historic Range: Orange and Purple

Yellow-legged Frogs - 3 Species
If you think the frog you are trying to identify iis a Yellow-legged frog, then look at the range maps of the three species below. The geographic location will help you identify which species of Yellow-legged frog you saw. The Sierra Nevada Yellow-legged frog occurs only in the Sierra Nevada Mountains. The Southern Mountain Yellow-legged Frog occurs at high elevations in the southern Sierra Nevada and in a few isolated streams in the San Gabriel, San Bernardino, and San Jacinto Mountains in southern California. In the Sierra Nevada Mountains, the Foothill Yellow-legged Frog is found at lower elevations than the Mountain Yellow-legged frog. It has declined in the Sierra Nevada foothills and is no longer found in Southern California.
Foothill Yellow-legged Frog - Rana boylii



	Underside of legs is yellow	Historic Range: Red

Some Rana boylii have red coloring on their back as can be seen on this juvenile.	Some juveniles have not yet developed the yellow coloring on the underside

Sierra Nevada Yellow-legged Frog - Rana sierrae



	Underside of legs is yellow	Historic Range: Red

Southern Mountain Yellow-legged Frog - Rana muscosa



	The underside of the legs of this species is also yellow but I have no photos. (See Rana sierrae above for example.)	Historic Range: Orange

American Bullfrog - *Lithobates catesbeianus*




	The underside is light in color with mottling. Some adults have yellow coloring underneath and calling males show a bright yellow throat sack.	Range of Introduction: Red

Juvenile © Jeff Ahrens

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