Tuesday, December 22, 2015

Green Treefrogs: Bright and Beautiful Denizens of North America

Green Treefrog
Green Treefrog
Courtesy of Clinton & Charles Robertson
There are currently more than one hundred species of frogs and toads in North America, among them is the very pretty Green Treefrog. These frogs are also known as cowbell frogs or rain frogs. The reason for the former is that their calls often sound like bells. The reason for the latter is that they have a habit of becoming noisy after it rains (during the active season).

Green Treefrogs are light green in color and the surface of their skin is very smooth. They may have white stripes with black borders running down their sides and the sides of their snouts. These frogs may also have yellow spots with black borders on their backs. They can grow to be between 1-1/4 and 2-1/2 inches in length as adults. Green Treefrogs are found mainly along the southeastern and Gulf coasts of the U.S. Their range goes north as far as Illinois.

Like many other frog species, Green Treefrogs are most noticeable when they are mating. The males of the species will congregate in specific breeding sites and start emitting an ‘advertising’ call in an attempt to attract mates. They are not very territorial. However, if another calling male gets too close to them at this time, they will emit a ‘warning’ call. Once a female chooses a male to mate with, she will often nudge him to get his attention. At this point, the male will clasp the female in what is called axillary amplexus. In other words, he will mount her and grip her from behind her forelimbs. He then fertilizes her eggs. If an unwitting male should attempt to mount another male or an unwilling female, the offended Green Treefrog will emit a ‘release’ call.

These frogs most often lay their eggs in lakes, ponds, swamps or standing water after a heavy rain. After the Green Treefrogs eggs hatch, it will take the tiny tadpoles a couple of weeks to a month to become frogs. During the tadpole stage, it will live off of aquatic plant life. Once the Green Treefrog reaches adulthood, it will live off of insects.

Green Treefrogs, and most other frogs, are more active at night than they are during the hotter daytime hours. They typically spend their days in burrows or hiding places that contain moisture. This is so that the frog’s skin will not dry out in the heat. However, they will also become inactive in cold weather, because they are cold-blooded. So, the best time to find a Green Treefrog is during mating season, which is usually from around March to around August. All you need to do is follow the sound of their mating calls.


Elliot, Lang, Gerhardt, Carl & Davidson, Carlos, The Frogs and Toads of North America, p. 44-47

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