Plains Spadefoot

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Plains Spadefoot

Plains Spadefoot
Spea bombifrons
Family: 
Pelobatidae (spadefoots) in the order Anura (frogs)
Description: 

These small toadlike amphibians have large, protruding eyes. The pupils of their eyes are vertical and elliptical. The hind legs are short, and the underside of each hind foot has a distinct, wedge-shaped spade, hence its name. There may be some green on the sides, and the back and sides might have tiny reddish “warts.” The small, irregular blotches on the back and legs are dark brown and may encircle the majority of their tiny warts. Call is an extended rasping or nasal “garvank” called at intervals of one-half to one second.

Similar species: The eastern spadefoot, which occurs in eastern counties along the Mississippi River and in southeastern Missouri, is distinguished by the absense of a raised area between the eyes and by having a sickle-shaped spade at the base of each hind foot.

Size: 
Length (snout to vent): 1½ to 2 inches.
Habitat and conservation: 
Primarily a species of the prairies and open floodplains of the Great Plains, in our state this species lives in the loose, sandy soils of the Missouri River floodplain. By day it hides in burrows in sandy soil. It becomes active at night, especially after heavy summer rains.
Foods: 
Earthworms and a variety of insects.
Distribution in Missouri: 
Missouri River floodplain from St. Louis to the northwestern corner of the state.
Status: 
Often called spadefoot toads, spadefoots are not true toads, nor are they true frogs, either. They’re named for a feature on the inner surface of their hind feet, a spadelike spur that helps them to dig their burrows.
Life cycle: 
Breeding is stimulated by warm, heavy rains. This species is an explosive breeder. Great numbers appear suddenly after a heavy late spring or summer rain. Breeding may be completed in a few nights, in temporary pools in flooded fields. A female can produce up to 2,000 eggs, which are usually attached to submerged plant material. The eggs may hatch in a few days. Hatching time and development rate vary with temperature, food supply, and the amount of oxygen in the water.
Human connections: 
Spadefoots have a remarkable tolerance to desiccation (drying out). They may lose up to half of their water content and still survive. They also produce compounds in their blood that keep them from freezing in winter. Researching such marvels sometimes provides a chance to improve human medicine.
Ecosystem connections: 
A predator of insects, the plains spadefoot and a host of other small insectivores function to control the populations of the hosts of those creatures. Meanwhile, the frogs, and their own thousands of eggs and many tadpoles, are eaten by larger predators.
Shortened URL
http://mdc.mo.gov/node/5338