| Species | Rana clamitans Latreille, 1801
= Lithobates clamitans |
| Family | Ranidae (True Frogs) |
| Status | None |
| State Rank | SE |
| Global Rank | G5 |
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This is a large, heavy-bodied frog with a distinct fold of skin (supratympanic fold) that extends from the eye, around the posterior edge of the external ear (tympanum) to the shoulder. Two distinct parallel ridges of skin (dorsolateral folds) are present on the dorsal sides of the body. The tympanum has a light yellow area in the center.
Adults attain sizes up to 100 mm snout-vent length. The dorsal color is tan, brown or olive-brown with little to no black speckling. Dark spots may be present on the dorsal surface. Dark bands are present on the legs. Adults have green pigmentation on the sides of the head. Ventrally the body and legs are white to cream colored. Females may have some dark chest mottling. Juveniles resemble adults. Mature males have a tympanum much larger than the size of the eye, whereas females have a tympanum similar in size to the eye. Mature males also have a bright yellow throat and gray swollen pads (nuptial pads) on the thumbs.
Larvae- The tadpole has an oval body with dorsal eyes. The dorsal fin terminates on the body and the tail tip is pointed. Large tadpoles (greater than 25 mm total length) are olive green dorsally with dark spots over the dorsal surface. The ventral surface is opaque and cream colored with a coppery sheen. The throat area has dark green mottling. Small tadpoles (less than 25 mm total length) are darker. Tadpoles may attain a length of 90 mm total length before metamorphosis.
Eggs – A female lays 1000-5000 eggs in a thin film at the water surface usually attached to vegetation. The eggs typically cover an area less than 30 cm in diameter. Three gelatinous layers (envelope) surround the egg (ovum).
Voice – The Green Frog produces a low-pitched, single-note advertisement call that sounds like a low-note banjo string being plucked “Clung!” This call may be given as a single note or repeated several times in a row. Alarmed Green Frogs, basking on water edges, produce a loud squawk as they dive into the water.
See Photos Page.
Frogs – The American Green Frog has been introduced to Washington in a few places. Documented occurrences are in Whatcom, Stevens and King counties.
No native Washington frog or toad has the supratympanic fold around the outer ear area. The exotic but common American Bullfrog can be easily distinguished from the Green Frog by the lack of dorsolateral folds. This trait is present and distinct in Green Frogs. Also, full-sized Bullfrogs are much larger than the American Green Frog.
Larvae- American Green Frog tadpoles are easy to distinguish from all native Washington tadpoles. Larger tadpoles are olive green with dark spots over the entire dorsal surface. The ventral surface is opaque cream-colored or yellow with coppery pigmentation and dark green mottling on the throat. American Bullfrogs tadpoles are similar but have distinct black flecks (not spots) over the dorsal surface and the belly has no metallic pigmentation. Bullfrogs also lack the dark green pigmentation on the throat.
Eggs – All native Washington frog species have globular egg masses and our toad species produce eggs in strings. The non-native American Bullfrog is the only species one will encounter in Washington with an egg mass similar to the American Green Frog. The American Bullfrog is widespread in the lowlands of Washington. The egg mass differs in being larger than 30 cm in diameter, being more than one egg layer thick, and individual eggs have only one gelatinous layer (envelope) surrounding the egg (ovum).
Both American Bullfrog and American Green Frog males produce vocalizations throughout the summer. This habit can be helpful in determining which species is breeding at a site. The American Bullfrog advertisement call is a loud, deep, bass call that is repeated several times in each series. The call has been described as “jug-o’-rum” and “br-rum.”
See Key Features Page.
No natural history papers have been published for the American Green Frog in Washington and neither of the authors has encountered this species in Washington. Life history traits are probably similar to the American Bullfrog. Calling likely commences in May or June. Egg laying likely takes place June to August. Tadpoles transform their first year or may overwinter and transform their second year.
In Washington, American Green Frogs have been documented in the Puget Trough Ecoregion and Canadian Rocky Mountain Ecoregion. More specifically, populations have been documented at Toad Lake, Whatcom County; Lake Washington, King County; and Lake Gillette, Stevens County. See Distribution Map.
For information on the complete range of this species, see NatureServe Explorer.
In their native range they occupy water bodies including wetlands, ponds, lakes, sloughs, creeks and rivers. Adults are primarily “shore frogs,” spending most of their time on the edges of the water body they occupy. Juveniles will disperse into terrestrial habitats during rainy periods. Breeding habitats include a variety of permanent water bodies. Green Frogs likely overwinter in permanent water bodies near sources of well-oxygenated water.
Males hold territories scattered around the edges of permanent water bodies. Males aggressively defend their territories by wrestling invading males out of the territory or under water. Females approach males at their calling stations, apparently selecting males for mating based on habitat conditions at the calling site. Egg development is rapid taking anywhere from a few days to a week depending on water temperatures. Tadpoles grow quickly and may metamorphose their first year or may over winter and metamorphose their second summer. The tadpoles can grow to large sizes, 90 mm total length or more, before metamorphosis.
The American Green Frog is native to the eastern United States. Populations introduced to Washington were probably for harvest of frog legs but little has been published regarding the species in Washington.
Any information on this species is of interest. Populations are present just north of the Canadian-American border. It is possible the species has expanded its range into northern Whatcom County.
Observations can be submitted to the Washington Department of Fish and Wildife WSDM database by contacting Lori Salzer by E-mail salzeljs@dfw.wa.gov. Natural History and other information can be submitted to Lisa Hallock by E-mail lisa.hallock@dfw.wa.gov.
The authors are unaware of any research on this species in Washington.
American Green Frogs are smaller than American Bullfrogs and therefore may not be as problematic to native amphibians when it comes to predation. Competitive interactions and introduction of disease are potential issues.
Dvornich et al. (1997), Harding and Holman (1992), Hecnar and M’Closkey (1996), Nussbaum et al. (1983), Stebbins (2003).
Hallock, L.A. and McAllister, K.R. 2009. American Green Frog. Washington Herp Atlas. http://www1.dnr.wa.gov/nhp/refdesk/herp/
Last updated: May 2009