The green frog (Rana clamitans), is a common anuran of the eastern United States. They, along with the bullfrog (Rana catesbeiana) are one of two aquatic frogs in Rhode Island because they are never far from the water, except during hibernation. In fact, they spend the majority of their time on the shores of lakes and ponds and the banks of rivers waiting for prey to cross their path. When approached, green frogs will typically leap into the safety of the water while letting out a loud cry. Hence, the old nickname ‘the screaming frog’.

Green frogs are commonly confused with bullfrogs during all stages of their life. As small tadpoles, the two species are difficult to impossible to separate but older tadpoles can be distinguished on close inspection. As adults, green frogs can be readily indentified from bullfrogs by the dorsal-lateral ridge whereas bullfrogs lack this ridge.

In Rhode Island, green frogs are widespread and common. They occupy a wide variety of habitats and appear to be less affected by development and degraded habitat than other amphibian species. In fact, some studies suggest that green frog populations have actually increased over the years and thus may benefit from manmade habitat alterations.

Identification

  • A large aquatic frog commonly confused with the bullfrog (Rana catesbeiana).
  • Dorsal-lateral folds are prominent, extending the length of the body. Bullfrogs do not have these folds.
  • The dorsum of the green frog is generally greenish-brown with darker spots or mottling.
  • The venter is creamy white- sometimes with dark spots and mottling, especially under the legs.
  • The legs have striped bars.
  • Mature males have yellow throats.
  • On the male, the tympanum (eardrum) is larger than the eye.
  • Some adult females are only slightly larger than the males (see SIZE below).
  • In larger tadpoles, the mottled tail with diffuse black spots and whitish vent distinguishes green frog from the similar bullfrog, which has distinct, small black spots on the tail and a yellowish vent.
  • Voice: The call is explosive, prolonged, and low-pitched (Dickerson 1906); producing a twang similar to the sound of plucking the bass string of a banjo, usually given as a single note, but sometimes repeated several times. Green frogs rarely engage in a chorus (Green and Pauley 1987).

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