Spea bombifronsplains spadefoot(Also: Sapo-de espuelas de las planicies)

Geographic Range

Found from southern Canada down through the US and into Northern Mexico (Bockstanz and Cannatella, 1998).


-Spea bombifrons- makes its home in the great plains. Grasslands with loose soil, and cultivated fields (Bockstanz and Cannatella, 1999). It burrows deeply and is capable of undergoing extended periods of time with no food, and will emerge from its burrow to feed at irregular intervals when the weather is favorable (Bartlett, 1999).

Physical Description

-Spea bombifrons- is 1.5 inches to 2.5 inches. The record size is 2 9/16 inches. It has a pronounced boss between the eyes (Conant, 1998). The color varies from gray to brown and often has a greenish tinge. There are four vague longitudinal stripes often present on its back. The small warts on its back are tipped with yellow or orange. Vertical pupils are like a cat's. Hind legs have single, wedge-shaped tubercle, or spade on inner surface. Toes are webbed. The skin is relatively smooth and moist like a frog, but they have some warts on their backs and live on land like a toad (Gov. of Alberta, 1999).



-Spea bombifrons- mates from May through August. The factor that affects breeding most is rain. Despite such a large window for breeding, as soon as the rain begins they breed. They mate and lay eggs in temporary ponds. Eggs are laid in clusters of 10-250 attached to vegetation, a few centimeters below the surface (Gov. of Alberta, 1999). They are explosive breeders. The eggs hatch within 48 hours and the tadpoles develop within 21-40 days (Gov. of Alberta, 1999). The tadpoles can reach a length of 68 mm. They are colored light grey or brown on top and lighter underneath.

The mating call is short and sounds somewhat like a duck. There are two distinct calls. The first is a short resonant bleat of approximately 0.5 seconds at intervals of 0.5-1 second. The second call is a low-pitched raspy snore lasting approximately 1 second (Bockstanz and Cannatella, 1998).

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)


A nocturnal animal, hence the vertical pupils. They are hardly seen without rain. It burrows deeply underground backwards using the "spade" on its back feet.They burrow down backwards in a corkscrew-like motion. They have been found as deep as one meter below the surface(Gov. of Alberta, 1999).

Food Habits

-Spea bombifrons- eats a variety of invertebrates including ants and beetles. Another favorite is the earthworm (Gov. of Alberta, 1999).

Conservation Status

In Alberta it is on the Blue List, which means it is considered at risk, or vulnerable (Gov. of Alberta, 1999.) At the same time, this is a very common though seldom seen anuran in the United States.

Other Comments

-Spea bombifrons- has a unique skin secretion when irritated. The secretions smell vaguely like garlic, are distasteful, and may cause allergic reactions (Bartlett, 1999).


Andrew Brinker (author), Michigan State University, James Harding (editor), Michigan State University.



living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature


A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.


having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.


A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.


Bartlett, R., P. Bartlett. 1999. A field guide to Texas reptiles and amphibians. Houston, Texas: Gulf Publishing Co..

Bockstanz, L., D. Cannatella. 1998. Accessed November 1st 1999 at http://www.zo.utexas.edu/research/txherps/.

Conant, R., J. Collins. 1998. Reptiles and amphibians of Eastern/Central North America. New York, NY: Houghton Mifflin Company.

Government of Alberta, 1997-1999. Accessed November 8, 1999 at http://www.gov.ab.ca/env/fw/amphib/index.html.