Fowler's Toad Anaxyrus fowleri

Description: Adult Morphology: A medium-sized toad with warty tan or grayish skin. Though they are capable of changing colors (as are other frogs), Fowler's toads are generally lighter colored than American toads. Ventral coloration is light and the venter is either unmarked or with a single dark spot under the throat. Fowler’s toads have large, irregular, dark blotches dorsally, often enclosing more than three warts. The cranial crests are indistinct and the tibial warts are not enlarged. Juveniles are similar to the adults.

Size: Adult Fowler's toads are 2-3 in (40-70 mm) in length.

Larvae: Tadpoles are small, dark and essentially indistinguishable from American toads until near metamorphosis.

Eggs: Eggs are deposited in shallow water, in long ribbon-like strands of up to 10,000 eggs per female.

Similar Species: American toads (Anaxyrus americanus) are often found alongside Fowler's toads and the two can be difficult to distinguish from one another. The matter is further complicated by occasional hybridization between the two species. American toads rarely have dorsal blotches that enclose more than one or two large warts, whereas Fowler's toads often have blotches that enclose multiple smaller warts. While American toads may have heavy dark mottling ventrally, Fowler's toads usually have either one large spot or no dark coloration at all. American toads have enlarged tibial warts that Fowler's toads lack. The cranial crest of American Toads is pronounced and either disconnected to the paratoid gland or only connected via a spur while the Fowler's toad has a much less prominent cranial crest that sits directly on top of the paratoid gland. While coloration is by no means an absolute way to identify this species, American toads are more often reddish or brown in coloration while Fowler's toads tend to be grayish or olive-gray in coloration. While the two are sympatric (inhabit the same areas) throughout most of the state, there is some differentiation in habitat use with Fowler's toads being the more common species in sandy and dry environments.

Distribution: Fowler's toads are found throughout much of eastern North America from east Texas into Missouri and Illinois, east to northern Florida in the south and New Hampshire in the north.

Fowler's toads are common throughout the state, though they are most prevalent in the southern half of the state and in the northwestern sand prairies.

Activity: These toads are active from late spring to fall, emerging during mid to late April and disappearing some time from late September through October.

Breeding Season: Fowler’s toads begin calling in late April or early May and continue through early July. Breeding activity may be prompted anytime during the spring and early summer when heavy rain fills temporary pools and ditches. Eggs hatch within a few days and the larval period is relatively short with metamorphic frogs appearing only one to two weeks after breeding occurred.

Taxonomy: Fowler’s toads (Anaxyrus fowleri) are in the family Bufonidae alongside American toads (Anaxyrus americanus) in Indiana. Previously, this species was included in the genus Bufo, but has since been placed in the genus Anaxyrus. Hybridization occurs with American toads throughout the state, and the hybrids are often very difficult to distinguish, showing characteristics of both species. Recent genetic work has shown that this species may actually be composed of three morphologically indistinguishable, but genetically distinct groups.

Ecology: Habitat: Fowler’s toads are generalists that are most often associated with open, sandy areas. They will also inhabit rocky hills, upland forests, floodplains, suburban landscapes, and agricultural areas. There is substantial habitat overlap with American toads, though Fowler’s toads are generally more abundant in sandy and dry areas. During the summer, these toads are primarily nocturnal and are most active on warm, humid nights. Adults have distinct home ranges and can apparently hold the same foraging territory for multiple years.

Diet: These toads feed on a variety of invertebrates and often sit in wait for prey on warm nights.

Reproduction and Life History: Fowler’s toads are summer breeders that rely on shallow, ephemeral waters. They seem to be prone to breeding in temporarily flooded pools, ditches, and fields but will readily breed in the shallows of larger bodies of water such as rivers and reservoirs.

Call: Their call is a trill similar to that of American toads. Fowler’s toads have a lower-pitched, nasal-sounding call that is harsher than that of their close relative.

Conservation: Fowler's toads are widespread and adapt well to most habitats including heavily disturbed areas. In general, there are no immediate threats to the persistence of this species in Indiana. This being said, many natives to Indiana will comment on a perceived decline in toad populations during the mid-late 1900's. It is likely that this corresponds with a general decline in amphibian populations but toads are more often seen around buildings and their decline is therefore more visible.

Poisonous: It is a common myth that toads cause warts when handled, but this is in no way true. Toads do however, have mildly toxic secretions that are used as a defensive mechanism against predators. These are not dangerous to humans unless ingested, but it is wise to wash your hands thoroughly after handling this species.

Literature

Brodman, R. 2003. Amphibians and Reptiles from Twenty-three Counties of Indiana. Proceedings of the Indiana Academy of Science 112.1:43-54.

Clark, R. D. 1974. Activity and Movement Patterns in a Population of Fowler's Toad, Bufo woodhousei fowleri. American Midland Naturalist 92.2:257-274.

Conant, R. and J. T . Collins. 1998. Reptiles and Amphibians of Eastern and Central North America. Third Edition, Expanded. Houghton Mifflin, New York, New York

Klueh, S., J. Mirtl, and T. Shier. 2011. Anaxyrus fowleri. Fowler's Toad. Geographic distribution. Herpetological Review 42.2:236.

Klueh, S. and J. Mirtl. 2010. Anaxyrus fowleri. Fowler's Toad. Geographic distribution. Herpetological Review 41.3:374-375.

Masta, S. E., B. K. Sullivan, T. Lamb, and E. J. Routman. 2002. Molecular Systematics, Hybridization, and Phylogeography of the Bufo americanus Complex in Eastern North America. Molecular Phylogenetics and Evolution 24.2:302-314

Minton, S. A. Jr. 2001. Amphibians and Reptiles of Indiana. Indiana Academy of Science, Indianapolis, IN.

Pierson, T. P. 2012. Anaxyrus fowleri. Fowler's Toad. Geographic distribution. Herpetological Review 43.2:297.

Timm, A. and V. Meretsky. 2011. Anuran Habitat use on Abandoned and Reclaimed Mining Areas of Southwestern Indiana. Proceedings of the Indiana Academy of Science 113.2:140-146.

Distribution Map
Distribution map of Fowler's Toad (Anaxyrus fowleri)
Photographs