American Toad Anaxyrus americanus

Description: Adult Morphology: A large, stocky toad 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 (Anaxyrus a. charlesmithi) is smaller and usually reddish in coloration with reduced ventral pigmentation.

Size: This species may range from 2 to 4in SV length, but the smaller variant (Anaxyrus a. charlesmithi) only grows to around 2.5in.

Larvae: A small and dark tadpole rarely exceeding 1in in length. There is no patterning on the tail.

Eggs: Females lay their eggs in strands of up to 10,000 eggs.

Similar Species: The Fowler's toad (Anaxyrus 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.

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 (Anaxyrus a. charlesmithi) variant is restricted to southern Indiana where many populations show characteristics of both the smaller subspecies and the larger subspecies (Anaxyrus a. americanus) that is present throughout the state.

Activity: American toads are most active from March to October with winter activity being observed only rarely.

Breeding Season: 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.

Taxonomy: The eastern American toad (Anaxyrus americanus americanus) occurs throughout most of Indiana. The dwarf American toad (Anaxyrus americanus charlesmithi) has a spotty occurence throughout southern Indiana where it often integrades with the eastern American toad. The American toad belongs to the genus Anaxyrus and is in the family Bufonidae which is represented in Indiana by 2 different species. Previously, this species was included in the genus Bufo and many researchers contend that the name change was unneccessary, therefore making the change not widely accepted. In some populations this species hybridizes with the Fowler's Toad (Anaxyrus fowleri).

Ecology: Habitat: 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.

Diet: A variety of insects and spiders, as well as earthworms make up the bulk of this frog's diet.

Reproduction and Life History: 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.

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.

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

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.

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. and J. Mirtl. 2011. Anaxyrus americanus. American Toad. Geographic distribution. Herpetological Review 42.4:561.

Klueh, S. and J. Mirtl. 2011. Anaxyrus americanus. American Toad. Geographic distribution. Herpetological Review 42.2:236.

Klueh, S. and J. Mirtl. 2010. Anaxyrus americanus. American Toad. Geographic distribution. Herpetological Review 41.3:374.

Klueh, S., J. Mirtl, and N. Engbrecht. 2010. Anaxyrus americanus. American Toad. Geographic distribution. Herpetological Review 41.3:374.

Klueh, S., A. Garcia, and N. Engbrecht. 2009. Anaxyrus americanus. American Toad. Geographic distribution. Herpetological Review 40.4:445-446.

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

Pierson, T. P. 2012. Anaxyrus americanus. American Toad. Geographic distribution. Herpetological Review 43.2:297.

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