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Teacher Resource

Getting to Know Vernal Pool organisms - Fowler's Toad by The Buffalo Zoo

Course, Subject

Biology/Living Environment, Math, Science & Technology

Grade Levels

Commencement, 9th Grade, 10th Grade, 11th Grade, 12th Grade

Additional Information


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.

Portions Adapted From

Roger Tory Peterson Institute - Vernal Pool Monitoring Project and,
Vereecke, M. 2001. "Bufo fowleri" (On-line), Animal Diversity Web
Accessed March 12, 2004 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Bufo_fowleri.html

Classification Information

Photo by John White.

Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Amphibia
Order: Anura
Family: Bufonidae
Genus: Bufo
Species: Bufo fowleri


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.

    Did You Know?

    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.


    Diet: The adults eat insects and other small terrestrial invertebrates, but shy away from earthworms, unlike their close relative, Bufo americanus.
    As a tadpole, Fowler's toads use their mouth, which is rimmed with tooth-like structures, to scrape attached algae from rocks and plants. The tadpoles are also known to feed on bacteria and other organic material from the water.

    Geographic Range and Habitat

    Geographic Range: Fowler's Toad is commonly found in areas of the Atlantic Coastal Plain. Its range consists of New Hampshire to eastern Texas, eastern Arkansas, Missouri, and southeastern Iowa, eastward into Michigan through Ohio, and West Virginia to the Atlantic coast. Extensions include up the Hudson, Delaware, Susquehanna, Ohio, and other rivers.

    Habitat: Bufo fowleri prefers to live in open woodlands, sand prairies, meadows, and beaches. They like to burrow into the ground during hot, dry periods and in the wintertime.

    Natural History

    Natural History: There are some conflicting opinions about the behavior of Fowler's toad. One source indicates that this type of toad is completely nocturnal. Another source states that Fowler's toad is mostly active in the daytime, except during hot days or very cold days when it will burrow into the ground. Both sources agree on how Fowler's toad reacts to predators and the defenses they use to protect themselves. Potential predators of Fowler's toad include snakes, birds, and smaller mammals. One defensive behavior it will use is its coloration to blend into its surroundings. These toads are able to do this because they tend to have coloration that is more nature-like, or earth tone. Another defense includes a noxious secretion that comes from the large warts on their backs. If attacked, this secretion will irritate the predator's mouth and, if ingested, can be poisonous to smaller mammals. If roughly handled, Fowler's toads will also lie still on their backs and pretend to play dead.

    Organism Name

    Photo by Solon Morse.

    Common Name:Fowler's Toad
    Scientific Name:Bufo fowleri

    Physical Characteristics

    Photo by James Harding.

    Physical Characteristics: Bufo fowleri comes from the order Anura which are animals noted for having a toothless jaw and enlarged parotoid glands behind the eyes. They are usually brown, gray, or olive green in color and have black edged dark spots on its back, with a light middorsal stripe. In each of the dark spots there are found to be three or more warts. The belly is usually whitish and almost completely unspotted. Males are often found to be darker in color while females are found to be lighter. Bufo fowleri is noted for having a single dark spot on its otherwise spotless belly. Its body measures between 5 to 9.5 centimeters in length. Bufo fowleri tadpoles have a short oval body and a long tail with an upper and lower fin. Their size is 1 to 1.4 centimeters long.


    Reproduction: Fowler's toad is known to reproduce in warmer seasons of the year, usually between the months of May and June. Breeding sites are located in shallow waters that are very open, including farm ponds, lake edges, marshes, and woodland ponds. Breeding habits of Fowler's toad are very similar to the American toad. The male will migrate to the breeding sites where he will begin calling his mate in intervals that can last up to thirty seconds. The call often attracts both male and females which will cause mistaken identities in the breeding process. This mistake occurs when one male tries to mate with another male. Fortunately, the first male will realize the mistake right away because the other male will let out a chirping release call that informs the first one of his mistake. When the male finally meets his mate, the male will try to clasp the female from behind. From this position the male can fertilize 7,000-10,000 eggs. Fertilization is external.

    Eggs: The eggs are known to hatch in two to seven days. The tadpoles will begin to undergo the change into tiny toads thirty to forty days later. In one growing season, Fowler's toad may grow to sexual maturity, but slower growing individuals may take up to three years before they reach their sexual peak.

    Fowler’s Toad is a Facultative Species and may be found in vernal pools, but can reproduce in other aquatic habitats where they are available.


    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.


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