North American Green Frog

IUCN Red List

LC - Least Concern

NatureServe

N5 - Secure
S5 - Secure

Minnesota

not listed

North American Green Frog is a mid-sized, 2¼″ to 3½″ long, true frog. It is the second largest frog in Minnesota after only the American bullfrog. While officially listed as “North American Green Frog” by the SSAR to distinguish it from international species, it is commonly referred to as simply the “Green Frog” in local and regional contexts.

The back (dorsal surface) is smooth to moderately rough and green or brownish-green. It usually has small, irregular, dark spots and is usually brighter colored toward the front. Prominent folds on each side of the back (dorsolateral folds) extend from just behind the disk-shaped membrane covering the ear opening (tympanum) to just over halfway down the back. Another ridge begins just behind the eye and curves downward behind the tympanum.

The side of the face is green. The tympanum on males is larger than the eye. On females it is about the same size as the eye.

The belly is white and often has dark mottling on the throat, jaw, and under the hind legs. Males have a single inflatable vocal sac. It is internal, not visible. The throat on mature males is yellow.

The hind legs have dark horizontal bands. The webbing on the hind feet extends to the tips of the first through third toes, to the second joint on the fourth toe, and not quite to the tip on the fifth toe.

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The description above refers to the northern subspecies, Green Frog (Lithobates clamitans melanota).

Size

Total length: 2¼″ to 3½″

Voice

Amphibian Research and Monitoring Initiative (ARMI), Midwest Region

Frog and Toad Calls

Similar Species

North American American Bullfrog (Lithobates catesbeianus) is larger. It lacks a dorsolateral ridge.

Semi-permanent or permanent wetlands: large marshes, streams, deep ponds, larger lakes, and roadside ditches.

Behavior

North American Green Frogs are often seen on a shore within one quick leap to a body of water. They hunt by sitting still and waiting for prey to cross their path.

Lifespan

5 to 10 years

Life Cycle

Adults emerge from hibernation from April to June. Males call from May to July. Mating takes place in late spring or early summer. After mating, the female lays a single floating mass of 1,000 to 5,000 eggs in water. The mass is flat and about 12″ in diameter. The eggs hatch in 3 to 7 days, depending on temperature. Most tadpoles overwinter and metamorphose into adults the following spring. Males become sexually active one year after metamorphosis, females 2 or 3 years. Adults hibernate in the mud under debris, under stones, or under water that does not completely freeze.

Tadpole Food

Organic debris, algae, plant tissue, and minute organisms in the water.

Adult Food

Insects, crayfish, fish, snails, small snakes, other frogs—any animal that will fit in its mouth.