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The distribution of the Boreal Chorus Frog ranges from central Canada through Minnesota, North Dakota, and Montana, and southwest into Colorado and Utah. It enjoys the status of being the most widely distributed amphibian in Wyoming; its reach extends beyond the prairie and desert, up through the foothills, and into the montane and alpine life zones. It inhabits the temporary waters of snowmelt pools and rain puddles, as well as the more permanent water of marshes, ponds, and lakes. It is an abundant frog but is seldom seen because of its small size and secretive behavior. Even when observed it is often misidentified and thought to be the young of other larger species of frogs found in the state.
These are small frogs with snout-to-vent lengths (SVL) less than 2 inches. Their slender bodies are proportionately long but they have short hind legs and are weak jumpers. They share with the bullfrog an absence of dorsolateral folds that are common to other species of frogs in the state. The skin is grainy or pebbled and the dorsal surface consists of a gray, green, or brown background which is stained with irregularly shaped longitudinal streaks running the length of the body; this pattern extends down along the sides and onto the legs. Usually, one such streak begins at the tip of the snout, passes through the eye, and parallels the side of the body as it makes its way to the groin. Diagnostic of this species are the digits of the feet which are only slightly webbed and tipped with small suction pads.
The Chorus Frog is the first frog to begin calling in early spring, late March and early April at lower elevations and immediately after snowmelt at higher elevations. Males inflate a single vocal sac and emit a loud rasping call sounding like a thumbnail being drawn across the tines of a plastic comb. The chorus of many males can be vigorous and quite loud, but the entire choir is quickly hushed at the slightest hint of danger. Eggs are deposited in clusters of 20-100 and glued to submerged vegetation. Depending on temperature, hatching takes anywhere from a couple of days to over two weeks. Metamorphosis requires another 6-10 weeks, but it is common for a pond to dry up before metamorphosis is complete. Sexual maturity is reached in 1-2 years.