Northern Prairie Wildlife Research Center
| These Chorus Frogs, like other members of the genus Pseudacris, are small frogs with a loud voice. Their call is easily mistaken for that of a larger frog. Their maximum snout-vent length is about 1.5 inches long. Previously, these three species were regarded as one divided into four subspecies. Two of these four races, the Upland Chorus Frog and the New Jersey Chorus Frog, are still considered subspecies of each other and are now placed under the species name Pseudacris feriarum, the Southeastern Chorus Frog. These species are very similar in appearance and can be hard to distinguish from one another in areas where their range overlaps. Even their calls are quite similar. | |||||||||||||||
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| The Boreal Chorus Frog is characterized by very short legs, with the tibia (leg segment below the knee) being shorter than that of the Western Chorus Frog, which it resembles closely. Both are characterized by usually having 3 dark bands on its dorsal surface. In the Boreal Chorus Frog the cenral band may or may not be broken, while in the Western Chorus frog it is more likely to be solid. There are two more lateral stripes that pass from the snout through the eyem and terminate somewhere along the side of the frog. | |||||||||||||||
 
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| However, the color and pattern of the Boreal Chorus Frog is highly variable. They generally have a pale gray to brown background color, but some specimens may be red or a bright green as can be seen in the 6 photos above. Also, the three stripes are present to varying degrees and can be nearly absent. All of the specimens in the photos above come from the same area in North Dakota showing the high degree of variability within a population. | |||||||||||||||
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| The Boreal Chorus Frog is one of the earliest amphibians to emerge. They are usually out before the snow and ice has completely melted. The picture to the right was taken of one that had been found on a snow drift. You can just see the outline of melted snow around his body indicating that he had been there for awhile. |
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| These are photos of the Western Chorus Frog, Pseudacris triseriata. As you can see, they are not so different from the Boreal Chorus Frogs. You can usually determine which species you have by checking the range map below, but in regions where they overlap it may be difficult. The legs of the Western Chorus Frog are longer and the lower leg segment (below the knee) is longer in relation to the rest of the leg than in the Boreal Chorus Frog. The Western Chorus Frog is also much more likely to have a solid stripe down the middle of its back, but the stripes may not be visible as in the photo to the upper right. | |
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This is an example of an Upland Chorus Frog, Pseudacris feriarum feriarum. These frogs are highly variable and may or may not have three stripes on their dorsal surface. These stripes, however, are most often broken up into spots. There are also usually two lateral stripes that pass from the snout through the eye and into the groin. (In the Western Chorus frog it usually terminates before the groin.) This particular specimen is completely unspotted. However, it still retains the stripe through the eye. The New Jersey Chorus Frog, Pseudacris feriarum kalmi (not shown) usually has three broad, well defined dorsal bands. These two frogs are collectively called the Southeastern Chorus Frog, Pseudacris feriarum. |
U.S. Department of the Interior |
U.S. Geological Survey
URL: http://www.npwrc.usgs.gov/resource/herps/amphibid/species/chorus.htm
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Page Last Modified: Saturday, 02-Feb-2013 05:02:01 EST
Sioux Falls, SD [sdww55]
