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Green Frog (Lithobates clamitans)

The Green Frog is a prominent amphibian native to eastern Canada. During the mating season, these frogs can be found near shallow ponds, lakes, rivers and swamps, where they spend most of their time in the water. While less vocal than their bullfrog cousins, they are a fascinating subject for wildlife enthusiasts.

At a Glance – Green Frog

How can I tell a Green Frog from an American Bullfrog?

The fastest field check is the dorsolateral fold behind the eye.

• Green Frog fold: It continues down the back along the body.
• Bullfrog fold: It curves around the tympanum and stops.
• Visual variation: Green Frogs can vary a lot in colour and pattern, so structure is more reliable than colour alone.

Where do Green Frogs usually live in Québec?

They are mostly found in and around permanent freshwater habitats.

• Core habitats: Ponds, lake margins, marshes, and slow streams.
• Seasonality: Most detectable from late spring through early autumn.
• Water association: Unlike American Toad (Anaxyrus americanus), Green Frog usually stays close to water through most of the active season.

What does a Green Frog call sound like?

In the field, calls can include both isolated "gulp"-like notes and longer response sequences.

• Single-note pattern: A short "gulp"-like call can occur at irregular intervals.
• Sequence pattern: Longer call runs may occur, sometimes in response to nearby Green Frogs.
• Audio example: A local long-sequence recording is available on YouTube.

Identification and Similar Species

Green Frog is identified by its medium body size, green to brown colour tones, and especially by the dorsolateral fold that runs from behind the eye down along the back.

Visually, individuals can look surprisingly different from one another in colour tone, contrast, and spotting, which can make photo-based identification feel inconsistent.

It is most often confused with American Bullfrog (Lithobates catesbeianus), but the fold is the quickest field check: in Green Frog it continues down the body, while in bullfrog it curves around the tympanum and stops.

During breeding season, males often show a yellowish throat and can produce at least two call patterns in the field: a single "gulp"-like call at irregular intervals (sometimes minutes apart), and longer call sequences that may answer nearby Green Frogs.

For a local example of the long-sequence call pattern, see: YouTube recording.

Observed Behaviour - Québec (Field Recordings)

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  A close-up field recording of a Green Frog producing a long advertisement call sequence from the water's edge.

Best Locations and Seasons for Sightings

In southern Québec, Green Frogs are easiest to detect from late spring through early autumn, especially in warm periods when males call near the water edge.

Look along permanent ponds, lake margins, marshes, and slow streams, where they often stay partly submerged near shoreline vegetation.

Unlike American Toad (Anaxyrus americanus), Green Frog is strongly tied to water through most of the active season, even outside peak breeding.

My best local site for this species is Jardin Botanique de Montréal, and my first observation was in Boisé Des Douze, St. Hyacinthe.

"x" indicates the species was observed, while "-" indicates no observation. Lack of observation doesn't necessarily imply that the species is absent. Data is derived from my park visit journals.

Ecology and Behaviour

Distribution

Green Frog is native to eastern North America, including southeastern Canada and much of the eastern United States.

In Québec, it is a common amphibian in permanent freshwater habitats and adjacent wet shoreline zones (Wikipedia; AmphibiaWeb).

Introduced populations are reported in parts of western North America, where local ecological effects can occur through competition with native amphibians (Wikipedia; IUCN).

Diet

Green Frog is an opportunistic carnivorous predator.

• Primary prey: Insects, spiders, and other abundant invertebrates near water (AmphibiaWeb).
• Secondary prey: Small fish, tadpoles, and other small vertebrates when available (Wikipedia; AmphibiaWeb).
• Foraging pattern: Uses a sit-and-wait strategy from shoreline cover or shallow water (AmphibiaWeb).

References – Green Frog

Most content on this page is based on my direct field observations. General species background (taxonomy, range, and broader ecology) is informed by the sources listed below.

• EOL - Taxonomy and species profile
• Wikipedia - Broad species overview and background
• AmphibiaWeb - Biology, range, and ecology summary
• IUCN Red List - Global conservation status assessment

All content on this page — including photos, videos, and field audio recordings — was created by Karl-Heinz Müller, a Montréal-based wildlife filmmaker, sound recordist, and photographer. Founder of MUUUH and Québec Sauvage, he has spent over a decade documenting Canada’s natural habitats through immersive soundscapes and wildlife films. Learn more about Karl-Heinz

Last updated: 2026-05-28