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Canadian Herpetological Society





Société d'herpétologie du Canada



Lithobates clamitans melanota,

formerly Rana clamitans melanota

Northern Green Frog / Grenouille verte du Nord


Northern Green Frog

Description
The Northern Green Frog is a large, true frog with large, distinct tympanum and prominent dorsolateral ridges. It may be green, bronze or brown, or a combination but is typically green on the upper lip. The belly is white with darker lines or spots. There may be some irregular spotting on the back. It is distinguished from other frogs in that the dorsolateral ridges run only partway down the back and do not reach the groin. The hind legs have dark bars. Males have a bright yellow throat. Maximum adult size is 10 cm.

Call
The call of the Northern Green Frog is a deep twangy "gung" like a loose banjo string. It is similar to that of the Mink Frog, but more twangy and not repeated in rapid groups.

Confusing Species
Bullfrogs are superficially similar although they lack dorsolateral ridges and are much larger as adults. Mink Frogs may also be confused with Northern Green Frogs although the former has a yellowish belly, a musky odour and eyes slightly upturned. Mink Frogs also do not have bars on the hind legs.

Distribution
The Northern Green Frog is native to Manitoba, Ontario, Qué‚bec, New Brunswick, Nova Scotia and Prince Edward Island. It has been introduced to Newfoundland and British Columbia. It is widely distributed in the eastern half of the United States.

Habitat
Northern Green Frogs are most commonly found in or near shallow, permanent water such as springs, swamps, brooks and pond and lake edges.

Reproduction
Northern Green Frogs begin calling in late spring to mid-summer and may breed as late as August. Three or four small clutches of eggs are draped over submerged vegetation in permanent water. Tadpoles overwinter in water before transforming the following summer. Because of the extended breeding season and long larval period, tadpoles of various sizes and newly transformed frogs can be found during most of the spring and summer.

Natural History
Northern Green Frogs are quite aquatic although they may be seen basking on the shores of ponds, lakes and creeks. They eat a wide variety of insects and other invertebrates. Northern Green Frogs hibernate under water.

Conservation Concerns
This species is widespread and apparently stable although it is rare in Manitoba. Northern Green Frogs are introduced to British Columbia and Newfoundland.