American Toad Bufo americanus

Adult from Jefferson County

Identification

Adults are large, stocky toads with a wide variety of red, brown, and gray color variations. There may be some dark blotches dorsally, but these blotches encompass only one or two warts. Ventrally, there is usually some dark mottling or speckling and the legs have some indistinct banding. While the eastern American Toad (Bufo a. americanus) is variable in coloration, the dwarf American Toad (Bufo a. charlesmithi) is smaller and usually reddish in coloration with reduced ventral pigmentation. This species may range from 2 to 4 in SV length, but the smaller variant (Bufo a. charlesmithi) only grows to around 2.5 in.

Females lay their eggs in strands of up to 10,000 eggs. A small and dark tadpole rarely exceeding 1 inch in length. There is no patterning on the tails of the larvae.

Adult from Boone County
Tadpoles from Jefferson County

The Fowler's Toad (Bufo fowleri) can be difficult to distinguish from this species and the two occasionally hybridize. 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 the American Toad 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 identifiy 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.

Call

American Toads have a high pitched trill that generally lasts a few seconds, but may last up to 30 seconds. When picked up, males will often give a high pitched peeping call or broken trill that is also given when a male grabs another male by mistake during breeding. Listen to the call courtesy of the Indiana DNR.

Ecology and Conservation

This species is a generalist that inhabits a wide variety of habitats. They are found in moist upland woods, marshes, suburban areas, and along riparian corridors. They are often spotted hopping around by day, but on rainy nights large numbers of these toads may be seen crossing roads. Adults and juveniles are regularly encountered under rocks along creeks and in gardens and yards. Sometimes they can be found in loose soil, burrowed down in shallow holes with only their heads exposed. American Toads are most active from March to October with winter activity being observed only rarely. A variety of insects and spiders, as well as earthworms make up the bulk of this frog's diet.

Rocky stream from Union County
Rocky creek from Brown County

In Indiana, this frog breeds in almost any source of still water. They will utilize woodland pools, marshes, shallow backwaters of lakes, areas where a stream pools, and even artificial goldfish ponds for breeding. Amplexus takes place in shallow, calm water. The male clasps the female and as the females expels strands of eggs, the male fertilizes them externally. Oftentimes multiple males will attempt to clasp one female, resulting in a ball of toads clasped together in a breeding frenzy. This occasionally can result in individuals drowning. This species begins calling in late March and will continue breeding through most of May. In northern Indiana, breeding starts in April and may continue into June. After being deposited, the eggs may take anywhere from a couple days to a couple weeks to hatch. The larvae usually transform in June or July.

This species is widespread and adapts well to most habitats including heavily disturbed areas. There are no known immediate threats to the wellbeing of this species in Indiana.

Distribution

The American Toad occurs throughout much of eastern Canada and the eastern United States, but is absent from most of the southeastern states. This species occurs throughout Indiana except for much of the southwestern lowlands. The dwarf American Toad (Bufo a. charlesmithi) variant is restricted to southern Indiana where many populations show characteristics of both the smaller subspecies and the larger subspecies (Bufo a. americanus) that is present throughout the state.

Taxonomy

The American Toad has two recognized subspecies present in Indiana--the Eastern American Toad (Bufo americanus americanus) and the Dwarf American Toad (Bufo americanus charlesmithi). See the Distribution description above for details on where each of these subspecies is found. Frost et al. (2006) recommended placing these toads in the genus Anaxyrus, but Pauly et al. (2009) argue against this, instead suggesting that Anaxyrus be recognized as subgenera of the intact Bufo. The American Toad belongs to the family Bufonidae, which is diverse worldwide and is represented in Indiana by a total of two species.

Is it dangerous?

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 Cited

Brodman, R. 2003. Amphibians and Reptiles from Twenty-three Counties of Indiana. Proceedings of the Indiana Academy of Science 112:43-54.

Conant, R., and J. T . Collins. 1998. Reptiles and amphibians of eastern and central North America. Third edition, expanded. Houghton Mifflin, New York, NY.

Frost, D. R., T. Grant, J. Faivovich, R. H. Bain, A. Haas, C. F. Haddad, R. O. De Sa, A. Channing, M. Wilkinson, S. C. Donnellan, and C. J. Raxworthy. 2006. The amphibian tree of life. Bulletin of the American Museum of Natural History:1-291.

Klueh, S. and J. Mirtl. 2011. Anaxyrus americanus. American Toad. Geographic distribution. Herpetological Review 42:561.

Klueh, S. and J. Mirtl. 2011. Anaxyrus americanus. American Toad. Geographic distribution. Herpetological Review 42:236.

Klueh, S. and J. Mirtl. 2010. Anaxyrus americanus. American Toad. Geographic distribution. Herpetological Review 41:374.

Klueh, S., J. Mirtl, and N. Engbrecht. 2010. Anaxyrus americanus. American Toad. Geographic distribution. Herpetological Review 41:374.

Klueh, S., A. Garcia, and N. Engbrecht. 2009. Anaxyrus americanus. American Toad. Geographic distribution. Herpetological Review 40:445-446.

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

Pauly, G.B., D. M. Hillis, and D. C. Cannatella. 2009. Taxonomic freedom and the role of official lists of species names. Herpetologica 65:115-128.

Pierson, T. 2012. Anaxyrus americanus. American Toad. Geographic distribution. Herpetological Review 43:297.

Distribution Map
Distribution map of American Toad (Bufo americanus)
Photographs