Striped Chorus Frogs are characterized by a white or cream colored stripe along the upper lip, bordered by a dark brown stripe running through the eye from the nostril to the groin. There are usually 3 dark stripes running down the back, although these may be broken into rows of spots in some. Background color ranges from brown to gray or olive. The underside is white or cream colored, possibly with dark spots on the chin and throat. Their coloration makes them difficult to see in their usual habitat. Males have a yellow colored vocal sac that appears as a dark, loose flap of skin when not calling. The skin of Striped Chorus Frogs is typically moist and bumpy, and the toes end in slightly expanded toepads. Adult length is usually 1.9 to 3.9 cm, with males usually smaller than females. Striped Chorus Frog tadpoles have gray or brown bodies that are round in shape. Their tail fins are clear, often with dark flecks. Their intestinal coil can be seen through the bronze belly skin.
Striped Chorus Frogs are found from midwestern through eastern North America, from southern Quebec, in Canada, west to South Dakota and as far south as Kansas and Oklahoma.
Striped Chorus Frogs can be found in a variety of habitats, including marshes, meadows, swales, and other open areas. Less frequently they can be found in fallowed agricultural fields, damp woods, and wooded swamps. They use areas without permanent water, instead breeding in small ponds that often dry up in summer. This reduces predation on their eggs by fish or turtles, which will not be found in these kinds of ponds. However, in dry years Striped Chorus Frogs risk the ponds drying too quickly, resulting in total failure of all of their eggs for that year.
The rate of development of the eggs and larvae is dependent on water temperature, with specimens in colder water requiring more time for development. Maximum length before metamorphosis is about 3cm.
In Michigan, the breeding season of Striped Chorus Frogs begins in mid-March and runs through late May, although most activity occurs in April. These periods can vary, with breeding taking place earlier in the southern end of the range and later in the north. Breeding sites include the edges of shallow ponds, flooded swales, ditches, wooded swamps, and flooded fields. Breeding choruses early in the season can be heard on clear, sunny days, but shift to evenings or cloudy, rainy days as the season progresses.
Females lay lay 500-1500 eggs in several loose, gelatinous clusters attached to submerged grasses or sticks. Each cluster will typically have 20 to 300 eggs. Hatching generally occurs in 3 to 14 days and tadpoles transform into tiny froglets 40 to 90 days after that. Striped Chorus Frogs can mature and breed in less than one year.
After laying their eggs in clusters on vegetation there is no further parental care in Striped Chorus Frogs.
Most Striped Chorus Frogs will probably die as tadpoles or froglets. Once they reach adulthood, Striped Chorus Frogs may live for about 5 years.
Striped Chorus Frogs tend to remain close to their breeding grounds throughout the year. They often hide from predators beneath logs, rocks, leaf litter, and in loose soil or animal burrows. They will typically hibernate in these places as well. Striped Chorus Frogs are most active at night or in moist weather. They are mainly solitary, except when they form large breeding aggregations in the spring.
Picking the small end of a high quality fine tooth comb with a fingernail can reproduce the call of the western chorus frog. The call sounds like "Cree-ee-ee-ee-eek", rising in speed and pitch as it progresses. Striped Chorus Frog males use these calls to attract females to breeding sites during the breeding season. Striped Chorus Frogs also use their keen vision to capture prey.
Striped chorus frogs eat a variety of small invertebrates, including ants, flies, beetles, moths, caterpillars, leafhoppers, and spiders. Newly formed froglets feed on smaller prey, including mites, midges, and springtails. Tadpoles are herbivorous, foraging mostly on algae in the water.
Striped Chorus Frogs help to control insect populations where they live, they also act as an important food source for their predators.
Striped Chorus Frogs (and most other frogs) act as critical indicator species of habitat quality. Because the larval and adult forms of this species occupy different levels of the food chain, deformities that occur can be the result of contamination of either their aquatic or terrestrial habitats. This makes this species valuable in determining the overall health of both ecosystems. The permeable skin of Striped Chorus frogs makes them particularly vulnerable to contaminants.
Striped Chorus Frogs can be common to locally abundant, although some areas have shown a decline in their numbers. One subspecies is listed as special concern in the state of Michigan. This species appears to be quite tolerant of human activities, considering its presence in agricultural and suburban areas. Caution must be exercised during agricultural practices, as runoff containing pesticides, herbicides, and fertilizers often fills breeding ponds, exposing eggs and larvae to contamination.
Kevin Gardiner (author), Michigan State University, James Harding (editor), Michigan State University.
Conant, R., J. Collins. 1991. Peterson Field Guides: Reptiles and Amphibians of Eastern and Central North America. New York: Houghton Mifflin Company.
Harding, J. 1997. Amphibians and Reptiles of the Great Lakes Region. Ann Arbor, MI: The University of Michigan Press.