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A Guide to the Amphibians
and Reptiles of California





Identifying Red-legged and Yellow-legged Frogs in California

 






California Frogs and Toads:




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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
foothill yellow-legged frog comp foothill yellow-legged frog comp  
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
frog frog range map
Northern Red-legged Frog Northern Red-legged Frog
Northern Red-legged Frog Northern Red-legged Frog
Northern Red-legged Frog Northern Red-legged Frog

Underside of legs is reddish Range: Red and Purple
     
California Red-legged Frog - Rana draytonii
California Red-legged Frog California Red-legged Frog range map
California Red-legged Frog frog
California Red-legged Frog California Red-legged Frog
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
frog frog range map
foothill yellow-legged frog foothill yellow-legged frog
Foothill Yellow-legged Frog foothill yellow-legged frog

Underside of legs is yellow Historic Range: Red
foothill yellow-legged frog foothill yellow-legged frog  
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
Sierra Nevada Yellow-legged Frog frog range map
Sierra Nevada Yellow-legged Frog Sierra Nevada Yellow-legged Frog
Sierra Nevada Yellow-legged Frog Sierra Nevada Yellow-legged Frog
  Underside of legs is yellow Historic Range: Red
     
Southern Mountain Yellow-legged Frog - Rana muscosa
frog frog range map
Southern Mountain Yellow-legged Frog Southern Mountain Yellow-legged Frog
Southern Mountain Yellow-legged Frog Southern Mountain Yellow-legged Frog
  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
American Bullfrog American Bullfrog American Bullfrog California range map
American Bullfrog American Bullfrog
American Bullfrog American Bullfrog
American Bullfrog American Bullfrog
  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
American Bullfrog American Bullfrog  
Juvenile © Jeff Ahrens  
     

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