Amphibians

Chorus Frog

Pseudacris · also called chorus frogs, western chorus frog

Least Concern ↓ insectivorecarnivore Rivers & wetlands Temperate grassland Temperate forest

A chorus frog is a small, striped, unshowy frog that announces spring across most of North America. On the first mild night after the thaw, hundreds of males gather in a flooded meadow or a roadside ditch and call together, a rising pulsed trill that sounds exactly like a thumbnail run down the teeth of a stiff comb, multiplied into a wall of sound.

Overview

Chorus frogs are the genus Pseudacris, a dozen or so small species across North America, from the Gulf Coast to the edge of the subarctic and high into the Rockies. They are members of the tree frog family that stay near the ground, living in wet meadows, marshes, ditches, and prairie potholes — more open country than the true tree frogs use. They are insectivores of ants, beetles, flies, and spiders.

First frogs of spring

Chorus frogs breed very early, often with ice still on the pond, calling on the first nights above about 5 °C. The spring peeper is in the same genus, so the peeping and the comb-trilling heard together on an early spring night are two chorus frogs side by side. They survive freezing by flooding their tissues with glucose antifreeze while hibernating on land, then thawing and calling within days of the snow melting.

Racing the puddle

They favour shallow, temporary, fish-free pools that dry by midsummer — a predator-light nursery, at the cost of a race against the drying water. Eggs and tadpoles can finish in six to eight weeks, and a late frost or early drought can erase a whole year’s breeding.

Status

Most species are Least Concern and adapt well to farmland and suburbs, but the trend is decreasing, and the Great Lakes and St Lawrence populations of the western chorus frog are federally listed and declining in Canada as small wetlands are drained for development.

Chorus Frog: common questions

What does a chorus frog sound like?

The classic chorus frog call is a short, rising, pulsing trill, often written as crreek or prreep, that sounds remarkably like dragging a fingernail slowly across the teeth of a stiff comb. Each call lasts about a second and males repeat it every few seconds. Heard alone it is modest, but chorus frogs call in dense aggregations, and a chorus of a few hundred males in a flooded field produces a loud, pulsing wall of sound that carries for hundreds of metres and is one of the defining sounds of early spring across much of North America. The spring peeper, a close relative, adds a separate high, clear, single peep to the same ponds.

Is a chorus frog the same as a spring peeper or a tree frog?

They are all in the tree frog family, Hylidae, and the spring peeper is actually in the same genus as the chorus frogs, Pseudacris. The chorus frogs and the peeper are the small, mostly ground-dwelling members of the family that breed early and live in open, grassy wetlands. The animals usually called tree frogs, such as the grey tree frog and the green tree frog in the genus Hyla, are larger, have bigger adhesive toe pads, genuinely climb trees and shrubs, and breed later in the year. So a chorus frog is a kind of tree frog in the broad family sense, but it behaves nothing like the tree-climbing ones.

How do chorus frogs survive freezing?

Chorus frogs hibernate on land, tucked under logs, bark, and leaf litter rather than at the bottom of a pond, which exposes them to sub-zero temperatures. They survive by being freeze-tolerant. As ice begins to form in their body, their liver floods the blood and tissues with glucose, which acts as an antifreeze inside the cells and controls where ice can form, keeping it in the body cavity and under the skin rather than inside cells where it would be lethal. Breathing and heartbeat stop while the frog is frozen, and resume within hours of thawing. This is why chorus frogs can be calling from a pond within days of the snow melting.

Why do chorus frogs breed in ditches and puddles that dry up?

Because temporary water has one big advantage, which is the absence of fish. Fish are major predators of frog eggs and tadpoles, and any pool that holds water year-round tends to accumulate them. By breeding in shallow, fish-free pools, flooded fields, and roadside ditches that fill with snowmelt and spring rain and dry out by summer, chorus frogs give their offspring a predator-light nursery. The trade-off is a race against the drying pool, so chorus frogs breed as early as possible and their tadpoles develop fast, sometimes completing metamorphosis in six to eight weeks. A late frost or an early drought can wipe out a whole year's breeding.

Sources & further reading

Written by HideShark Editorial Team · reviewed by HideShark Science Desk. Published September 10, 2026. Last updated September 10, 2026.

Quick facts

Scientific name: Pseudacris
Diet: Small invertebrates such as ants, beetles, flies, small spiders, mites, and springtails, gleaned from low vegetation, leaf litter, and the ground near water, with the tadpoles grazing algae and decaying plant matter in the breeding pools
The comb call: A male chorus frog calls with a rising, pulsed crreek that is almost universally compared to running a thumbnail slowly along the teeth of a plastic pocket comb, and a full chorus of dozens or hundreds of males is loud enough to be heard from several hundred metres away
Among the first frogs of spring: Chorus frogs breed very early, often while ice still rims the pond, calling on the first nights above about 5 degrees Celsius in late winter and early spring, and the boreal chorus frog calls further north and at higher elevations than almost any other North American frog
A dozen or so species, hard to tell apart: The genus Pseudacris includes the western, boreal, upland, southern, mountain, and New Jersey chorus frogs and several others, most of them small, brown or grey, and marked with three dark stripes down the back, and they are often identified more reliably by call and location than by appearance
The spring peeper is a chorus frog: The spring peeper, with its single high peep, is placed in the same genus, Pseudacris, so the loud peeping and the comb-like trilling heard together on an early spring night are two members of the chorus frog group calling side by side
They can freeze and thaw: Chorus frogs overwinter on land under logs and leaf litter and tolerate their body fluids partly freezing, flooding their tissues with glucose as a natural antifreeze so that ice forms only in safe spaces outside the cells, which lets them survive hard frosts and emerge to breed as soon as it thaws
Breeding pools are here and gone: Chorus frogs favour shallow, temporary, fish-free pools, flooded fields, and ditches that dry up by midsummer, racing through egg-laying and tadpole development in as little as six to eight weeks before the water disappears
Range: North America, from the Gulf of Mexico north across the United States and through much of Canada to the edge of the boreal forest and the subarctic, and into the Rocky Mountains at high elevation, in wet meadows, marshes, flooded grassland, roadside ditches, prairie potholes, bog edges, and open woodland with temporary pools, generally in more open habitat than the true tree frogs.
Conservation status: Least Concern ↓ ≈ Most chorus frog species are common and assessed as Least Concern, and their willingness to breed in ditches, wet pastures, and stormwater ponds helps them persist in farmed and suburban landscapes, but several populations are in trouble, most notably the Great Lakes and St Lawrence populations of the western chorus frog in Ontario and Quebec, which are federally listed and declining as small wetlands are drained and filled for housing and agriculture, and the mountain chorus frog has contracted in parts of Appalachia in the wild