American Toad (Bufo [Anaxyrus] americanus)

American Toad (Bufo [Anaxyrus] americanus)

Photos by J.D. Willson unless otherwise noted

Description: American toads are approximately 51-90 mm (2.0-3.5 in) in length and generally have a brown or gray coloration, although some individuals may even be reddish (brick red in the extreme case), olive, or tan. Their base color is often accented with yellow or tan patches that contain randomly distributed dark spots across the back in most cases. A light stripe extends down the middorsal. The venter is light with numerous dark markings. American toads are sexually dimorphic – males are typically smaller than females and have dark throats during the breeding season. The skin of these toads is dry and densely covered with warts. They usually have only one or two warts in the largest of the dark spots on the back. There are enlarged warts on the tibia. Behind each eye lies a swollen parotoid gland. The postorbital ridges are separated from the paratoids completely, but are often connected by a short spur. Two subspecies exist: the eastern American toad and the dwarf American toad. In addition, hybridization frequently occurs between American toads and both Fowler’s toads and southern toads where their ranges overlap.

Distribution and Habitat:

As the most broadly distributed species of the family Bufonidae in North America, the American toad can be found in parts of every southeastern state except for Florida. Their range extends north to eastern Manitoba, parts of Ontario and Quebec, the Maritime Provinces, and southern Newfoundland. It also covers the northeastern United States and the Midwest states to eastern Kansas and the Dakotas. Dwarf American toads even reside as far as northeastern Texas and eastern Oklahoma. American toads live in terrestrial habitats ranging from hardwood or pine hardwood to white pine-eastern hemlock forests. These toads are not averse to open fields and pastures or residential areas either, as long as the habitat contains accumulated leaf litter, sandy or loamy soil for burrowing, moist hiding places, and an abundance of food. They require shallow bodies of water that are free of fish to breed – these may be temporary ponds, roadside ditches, or the margins of lakes.

Reproduction and Development: January or February marks the beginning of the breeding season for American toads in the Southeast, although it lasts from March to July in most of their range. Males will gather in choruses to beckon females to wetlands- they usually call at night, but also sing on warm, wet days during the height of the season. The call of the male is a long, high-pitched, musical bu-r-r-r-r that is 6-30 seconds in duration. The female selects a mate and he grasps her behind her forelimbs, encouraging her to deposit 2,000-20,000 eggs in double, gelatinous strands. The egg strings attach to vegetation or lie at the bottom as deep as 2-4 inches until they hatch 3-12 days later. Tadpoles develop for up to 2 months before becoming toadlets. They reach reproductive maturity at 2-3 years.

Habits: Encountered infrequently during the summer, American toads are inactive during hot, dry periods and from late fall until breeding begins early in the year. They are most active at night, spending the day hiding in burrows or underneath logs, forest ground litter, or rocks. These toads show hiding spot fidelity, sometimes returning to the same location every day. During the non-breeding season, individuals have a home range of several hundred square feet, but adults may travel more than half a mile during the breeding period. Adult American toads eat a variety of small insects including ants, beetles, moths, and earthworms. Tadpoles consume aquatic organic matter such as algae, detritus, dead fish, or other tadpoles. Predators of adults include several species of snakes, birds, and mammals. Some are immune to the toxic secretions of the parotoid glands and skin, while others have adapted to tolerate the chemicals. When threatened, American toads will crouch and remain still, relying on camouflage. In some instances, especially during encounters with snakes, they will inflate their body and extend their hind limbs so as to appear larger. Toxins are also found in eggs, though they are lost in the larval stage. Predators of tadpoles include predaceous diving beetles, giant water bugs, dragonfly naiads, crayfish, and birds. They swim in dense schools for defense.

Conservation:American toads are listed as a species of least concern due to their large geographic range and their ability to thrive in a variety of habitats.

Pertinent References:
Conant, Roger, and Joseph T. Collins. A Field Guide to Reptiles & Amphibians: Eastern and Central North America. 3rd ed. Boston: Houghton Mifflin, 1998.

Dorcas, Mike, and Whit Gibbons. Frogs and Toads of the Southeast. Athens: University of Georgia, 2008.

Jensen, John B., Carlos D. Camp, Whit Gibbons, and Matt J. Elliott. Amphibians and Reptiles of Georgia. Athens: University of Georgia, 2008.

Account Author: Lindsay Partymiller, Lauren Maynor

American Toad (Bufo [Anaxyrus] americanus)
American Toad (Bufo [Anaxyrus] americanus)
Dorsal coloration - note only one or two warts within blotches