The boreal chorus frog, formerly called the western chorus frog in our state, is a small frog that may be gray or tan; it has 3 wide, dark stripes or a series of spots down the back, and a wide, dark stripe passing through the eyes and extending along the sides. There is usually a dark marking on the head between the eyes, and the upper lip is white. The belly is white, sometimes with a few gray spots on the throat and chest. Breeding males have dark throats. The call is a rasping, vibrating prrreeep that sounds similar to running a fingernail over the teeth of a pocket comb.
Hylidae (treefrogs and allies) in the order Anura
Common Name Synonyms
Western Chorus Frog
Length: ¾ to 1½ inches.
Where To Find
Statewide, except in southeastern Missouri, where it hybridizes with and also is replaced by the upland chorus frog.
This frog is most abundant in prairies but also occurs on agricultural lands, in large river floodplains, and on the grassy edges of marshes. After breeding season, they take shelter in animals burrows; under boards, logs, or rocks; in clumps of grass; or in loose soil. Breeding sites are usually in flooded fields, ditches, woodland ponds, marshes, and river sloughs as well as farm ponds. This is often the first frog to become active in the spring.
Boreal chorus frogs eat a variety of small insects and spiders.
Common. Our species was long considered the “western chorus frog,” Pseudacris triseriata, but scientists now recognize it as a separate species, the boreal chorus frog. Our frogs haven’t changed — only their name and species designation. Also, western chorus frogs still exist as a species — but not in Missouri. As ornithologists do with bird names, herpetologists assign official common names to reptile and amphibian species to correspond exactly with the scientific names.
Breeding begins in late February or early March and peaks in April. Males chorus in temporary bodies of water and in fishless farm ponds. The male fertilizes the eggs as the female lays and attaches them to submerged grasses just below the surface, in clusters of 5–300. These hatch within a week, depending on water temperature. Metamorphosis occurs in 6–8 weeks. This species overwinters in the ground and does not burrow very deep. A natural antifreeze in their blood keeps them from freezing.
These frogs help control populations of sometimes-troublesome insects. Also, because they are sensitive to pollutants, they are an indicator species, whose presence and population numbers help us gauge the health of their ecosystem.
These small frogs prey on numerous insects and spiders, helping to control their populations, but they also fall prey to many larger predators at each stage of their life cycle.
About Reptiles and Amphibians in Missouri
Missouri’s herptiles comprise 43 amphibians and 75 reptiles. Amphibians, including salamanders, toads, and frogs, are vertebrate animals that spend at least part of their life cycle in water. They usually have moist skin, lack scales or claws, and are ectothermal (cold-blooded), so they do not produce their own body heat the way birds and mammals do. Reptiles, including turtles, lizards, and snakes, are also vertebrates, and most are ectothermal, but unlike amphibians, reptiles have dry skin with scales, the ones with legs have claws, and they do not have to live part of their lives in water.