Adults of this species are large, green to olive-colored frogs with an obvious green face. There may be some darker dorsal mottling, but some individuals have none. In males, the tympanum is much larger than in the females. This frog's underbelly is mostly white with some darker mottling present in most individuals. Banding is usually present on the legs. Dorsolateral folds are present. This species grows to around 3-4in snout-vent length.
Females lay up to 5,000 eggs in a film on top of the water. These eggs become large, olive-brown tadpoles that usually grow to around 4in length. The tailfins of tadpoles are heavily mottled.
The American Bullfrog (Rana catesbeianus) is most likely to be confused with this species. Green Frogs have a dorsolateral fold that American Bullfrogs lack and Green Frogs also have more distinct banding on the hind legs than American Bullfrogs. In general, American Bullfrogs grow much larger than Green Frogs.
Green Frogs have a distinct low-pitched single note call that is often likened to the plucking of a loose banjo string. The call occurs at irregular intervals. Listen to the call courtesy of Indiana DNR.
Ecology and Conservation
This species can be found in virtually any aquatic habitat. They seem to prefer cool, clear, flowing streams and rivers, but they are also found in woodland pools, lakes, or even stagnant muddy marshes. Green Frogs are often turned up under rocks, logs, and leaf litter near the water's edge. They may also be seen sitting around the edge of small pools and ponds. When disturbed, this species will promptly leap into the water, giving off a high pitched yelp, and burying themselves into the leaf litter or mud. Green Frogs may be seen crossing roads or hopping around out in the open near permanent water on rainy nights. Green Frogs are somewhat active year round in the southern part of the state. Here, they often spend time around springs and caves during the winter. They are most active from March to October. Green Frogs feed on a variety of invertebrates. They mainly feed on insects with spiders and mollusks being taken occasionally too. Green Frogs will occasionally prey on small fish and frogs as well.
In Indiana, this frog tends to breed in cool, permanent bodies of water such as woodland ponds and creeks. Amplexus occurs in shallow water and the eggs are fertilized externally by the males. Green Frogs typically start calling sometime during May and will continue breeding sporadically throughout the summer. The frogs rarely continue calling into August. After being deposited, the eggs take a few days to hatch and the tadpoles transform sometime during that fall or the following spring depending on how late in the year the eggs were laid.
Green Frogs are wide spread and adapt well to habitat disturbances. While American Bullfrogs may outcompete this species in some ponds, it not likely a major threat to the stability of Green Frog populations as this species breeds in a broader variety of habitats than does the American Bullfrogs.
The Green Frog is found throughout much of the eastern United States and Canada from Texas and Minnesota to the east coast. The species is common and widespread throughout Indiana.
The northern Green Frog (Rana clamitans melanota) is the only subspecies that occurs in Indiana. Frost et al. (2006) recommended placing these frogs in the genus Lithobates, but other authors argue against this, instead suggesting the recognition of subgenera within the monophyletic Rana (e.g., Pauley et al. 2009; Yuan et al. 2016). Green Frogs belong to the family Ranidae, which is diverse and widespread worldwide and includes eight species of frogs in Indiana.
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