The Great Plains toad is a medium-sized toad with large, paired, dark blotches on the back and sides. The blotches may be gray, brown, dark green, green, or yellow. Each blotch is usually encircled with white or light tan and contains many "warts." A light, narrow stripe may run down the back of some individuals. The large, wartlike paratoid gland behind each eye is kidney shaped and is connected to the bony cranial crest that is above each eye. The two bony crests unite between the eyes and form a raised hump (called a “boss”) on the snout. The belly is cream-colored with little or no spotting.
Makes a loud, rapid, piercing, metallic, chugging “chee-ga, chee-ga, chee-ga” or chattering trill that lasts 20–50 seconds. The inflated vocal sac of calling males is sausage-shaped and extends forward and above the snout. Compared to the American toad's rather melodious trilling, a chorus of Great Plains toads sounds chattering and more metallic.
Similar species: The Great Plains toad is distinguished from Missouri's other true toads by the raised boss on the snout.
Members of the true toad family (Bufonidae) live nearly worldwide, except for New Zealand, Australia, Madagascar, and the polar regions. The family comprises 47 genera with more than 590 species. In the United States, there are 19 species of true toads, and all are members of the genus Anaxyrus. In Missouri, there are 4 species of true toads, with 1 additional subspecies.
True toads have dry skin compared to frogs. They have no teeth, lack extensive webbing on the hind feet, and have large, wartlike parotoid glands behind their eyes. Numerous “warts” over most of their bodies produce toxic skin secretions that are irritating to a predator’s mucous membranes.
Adult length (snout to vent): 2 to 3½ inches; occasionally to 4½ inches. Females are larger than males.
In Missouri, restricted to the Missouri River floodplain, from the northwestern corner to the central part of the state.
Habitat and Conservation
The Great Plains toad has a limited distribution in Missouri. In our state, it occurs only in the loose, sandy soils of the open floodplains along the Missouri River from central to northwest Missouri. In Missouri, it avoids forested areas and upland prairies. In other states (in the Great Plains, to our west), this species occurs in mixed-grass and shortgrass prairies and frequents open floodplains.
During Missouri River flooding in the summer of 2019, thousands of Great Plains toads were observed on roads and yards as they sought to escape the rising water.
As with most other toads, this species is primarily nocturnal, hiding in underground burrows by day and emerging at night to feed. It uses deeper burrows to escape both extreme hot and extreme cold temperatures. They can dig burrows themselves, or they can use mammal-created burrows to about 40 inches deep.
At night it emerges to feed on ants, beetles, and other insects.
Toads are well-known for their consumption of large numbers of insects. During summer nights, toads often catch and eat insects as they fall to the ground under outdoor lights.
Populations are considered vulnerable in Missouri, but found throughout the Great Plains. Listed as a Missouri species of conservation concern due to its narrow range, destruction or modification of breeding wetlands, and limited knowledge on basic biology.
Breeding occurs in shallow, flooded fields along the Missouri River floodplain. Breeding aggregations form from April through July, always after heavy rains. They select rain-filled ditches, temporary pools, and flooded fields as breeding sites, preferring shallow water only up to about 12 inches deep. Calling begins when air temperatures warm to above 57 F. Females can lay several thousand eggs, probably averaging about 11,000 at a time. They may have 2 clutches in a single year. The eggs hatch within about a week, and the tadpoles metamorphose into tiny toadlets (less than ½ inch long) in about 17–49 days, varying with water temperature.
In Missouri, this species appears on the surface from April through early October.
Management of this species in our state should focus on maintaining shallow, temporary wetlands for breeding and tadpole growth.
Because this species occurs within agricultural areas of the Missouri River floodplain and has a voracious appetite for agricultural insect pests, the Great Plains toad is considered economically important.
As predators of insects, these amphibians help decrease populations of many insects that are pests to humans (not just the pests that damage crops). Additionally, their beautiful and strange singing adds to the magic of a Missouri evening.
Contrary to superstition, toads do not cause warts on humans.
Toads are predators that help keep populations of ants and other insects in balance. They, and especially their eggs, tadpoles, and young toadlets, become food for both aquatic and terrestrial predators ranging from water bugs to fish to grackles to raccoons.