Geographic Range: Found in the United States and Canada from Maine and the Maritime provinces of Canada through the Great Lakes region and into western Ontario and Oklahoma, south to eastern Texas, east into northern Florida and extending up the entire east coast of the United States.

Habitat: Green frogs are found in a wide variety of habitats that surround most inland waters, such as: swamps, wooded swamps, ponds, lakes, marshes, bogs, banks of slow moving rivers and streams, oxbow lakes, sloughs, and impoundments. Juveniles may disperse into wooded areas or meadows during times of rain. Green frogs will overwinter in the water usually buried in the substrate.

Physical Description: Green, greenish brown, brownish, yellowish green and olive, with some rare individuals being blue. Generally brighter in front with small irregular black spots; legs have dark transverse bands; yellowish or white below; males usually have a bright yellow throat; tympanum (eardrum) is large; in males the tympanum is much larger than the eye and females tend to have a tympanum the same size as the eye; dorso-lateral ridge is well defined and extends from the back of the eye posteriorly down the body; toes are well webbed; first fingers do not extend beyond the second; the tibia and femur are equal to ½ body length; adult length is 3-5 inches.

Diet: Green frogs are primarily carnivores, and eat a wide variety of prey items such as insects (terrestrial and aquatic), and other vertebrates (small snakes and frogs). They have been termed as "sit and wait" predators eating whatever comes within reach. Tadpoles will feed primarily on diatoms, algae, and minute quantities of small animals such as zooplankton.

Reproduction: In green frogs it is the female who chooses her mate. Females will choose a mate based on the desirability of his territory for egg laying. Breeding takes place in late spring; variations in temperature and region can influence actual breeding times. The length of the breeding season is 1-3 months and occurs in a variety of habitats, such as swamps, ponds, marshes, bogs, and slow moving streams. Satellite males may also be present during the breeding period of green frogs. A satellite male is described as a smaller male, unable to acquire and defend territories, and are often found in areas protected by a larger male. The satellite male will wait for the opportunity to mate with a female that is responding to the larger more dominant male frog's vocalizations.

Eggs: Once a female has chosen a male, amplexus will begin. During amplexus, 1000-7000 eggs may be laid. The egg masses float on the water surface or hang from emergent aquatic vegetation. Multiple egg clutches are possible, the second egg clutch is on average smaller, with 1000-1500 eggs. Eggs will hatch in 3-7 days and will complete the tadpole stage of development in 3-22 months.

The Green frog is a Facultative Species and may be found in vernal pools, but can reproduce in other aquatic habitats where they are available.

Natural History: Males establish breeding territories and maintain them throughout the breeding period. Territories are found in shallow water and are reported to be 3-20 feet in diameter. Males will usually call from selected areas within the territory while occasionally patrolling the parameter . Their advertisement call has been compared to the pluck of a loose banjo string. If another male enters his territory the male will give a series of growls followed by an advertisement call. Green frogs produce as many as six different calls. Males attracting a mate give the advertisement call and a high-intensity advertisement call. Male frogs defending a territory from an intruding male usually give aggressive calls and growls. The release call is given by non-receptive females and by males accidentally grabbed by another male. Finally, the alert call is given by males and females when startled or attacked by a predator.

Vernal Pool Conservation

What you can do:

• Resist the temptation to clean up in and around vernal pool habitats. Leave trees, bushes, and understory vegetation, as well as brush, logs, and dead trees.
• Leave a buffer of natural vegetation around the pool for as great a distance as possible back from the edge of the pool's high-water mark. A buffer of at least 100 feet will help maintain water quality, but will do little to protect amphibians living around the pool. Vernal pool breeders require at least 300 yards of natural habitat around their pools in order to survive.
• Do not fill in the pool, even when it is dry, by dumping leaves or other debris in it.
• In areas with more than one pool, try to maintain travel corridors of natural vegetation between them. If some clearing is necessary, avoid drastic alterations that remove most of the trees and other cover. If habitat alterations are necessary, conduct these activities between November and March, when amphibians are less likely to be present. Activities done when the ground is frozen will cause much less damage to the soil than those conducted during warmer months.
• Avoid activities that inadvertently alter the movement of surface water (hydrology) of the upland area that drains into the pool. Digging ditches and similar activities can change runoff into the pool, thereby altering its flooding cycle.
• Do not dig into the bottom of the pool, even when it is dry, as this will disturb the non-permeable layer of soil that allows the pool to flood.
• Work with local conservation commissions and other interested individuals to identify and document vernal pools in your area.

  *Adapted from the Audubon Society of New Hampshire and the Nongame and Endangered Wildlife Program of the New Hampshire Fish and Game Department.

Photo by Tom Lautzenheiser.

A vernal pool is a temporary or semi-permanent body of water, typically filled in the spring by snow melt and spring rain, and holding water for two or three months in the spring and summer.

Vernal pools form in contained basin depressions, meaning that while they may have an inlet, they have no permanent outlet forming a downstream connection to other aquatic systems. They are typically small, rarely exceeding 50 m in width, and are usually shallow. While most are filled with meltwater and spring rains, others may be filled during the fall or with a combination of seasonal surface runoff and intersection with seasonally high groundwater tables. Typical substrates are formed primarily of dense leaf litter. While most vernal pools are found in upland forest, several types have been identified, including floodplain basins, swamp pools and marsh pools.

Periodic drying is a key feature of the ecology of vernal pools. Drying precludes the establishment of permanent fish populations, which would otherwise act as predators on the eggs and larvae of species that live or breed in the pool. While a typical vernal pool is dry during at least part of the year, others may contain some water throughout the year (or for several years), but a combination of shallow water, summer heat, winter freezing, and periodic oxygen depletion prevent the establishment of fish populations.

Terms:

Obligate Species: Species must live or breed in vernal pools.
Facultative Species: Species may be found in vernal pools, but can reproduce in other aquatic habitats where they are available.
Dorsolateral ridge: Lines or folds of skin (usually gold colored) along the upper sides of some frogs in the family Ranidae.
Intercalary cartilage: An extra piece of cartilage in the toes of members of the Hylidae (tree frog) family. It causes the end of the toes to have a “stepped-down” appearance.
Parotoid glands: Large skin glands that appear as swellings on each side of the back of the head of toads (family Bufonidae) and some salamanders.
Tympanum: This is the external ear drum visible on the side of the head of most frogs.

Gillilland, M. 2000. "Rana clamitans" (On-line), Animal Diversity Web
Accessed March 30, 2004 at https://animaldiversity.ummz.umich.edu/site/accounts/information/Rana_clamitans.html

The Roger Tory Peterson Institute is a national, non-profit nature education organization with headquarters in Jamestown, New York, birthplace of world renowned artist and naturalist, Roger Tory Peterson (1908-1996). In collaboration with the Center for Applied Technologies in Education, the Roger Tory Peterson Institute has provided these animal profiles to offer a glimpse into the diversity of Vernal Pools in our region.