Scaphiopus holbrookiiEastern Spadefoot

Geographic Range

The distribution of the Eastern Spadefoot ranges from Southern New England to Florida. The range extends west to parts of Missouri, Arkansas, and Louisiana. The northern range borders southern Ohio and Illinois (Conant & Collins, 1998).

Habitat

The Eastern Spadefoot resides in areas that are usually sandy or loose soil. The habitats usually resemble the ones of the more arid regions of the Western Spadefoots.

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams

Physical Description

Scaphiopus holbrooki has a body length between 1 3/4 - 2 1/4 in. although the record was found to be 2 7/8 in. The Eastern Spadefoot, as the name implies, has an elongated spade on each hind foot that is extensively webbed. Only one spade is present on each foot and is usually black, horny, and has a spade-like tubercle on the inner surface (Dundee & Rossman, 1989).

The parotid glands are distinct. No boss in between the eyes. On the back of the toad there are two yellowish lines, one that starts at each eye, that run down the back. The formation of the two lines may resemble that of a distorted hourglass. Most of the species display an additional light line on each side of the body. The ground color of the toad is some sort of brown color, although there have been instances of species that are uniformly black or gray (Conant & Collins, 1998).

Development

Reproduction

The breeding season of the Eastern Spadefoot begins in March and continues through July, depending on the location of the species. Species that live in warmer regions may breed earlier than those located in a colder area (Oliver, 1955).

The beginning of the breeding season is marked by the occurrence of a torrential rainstorm. These rains produce large areas of surface water (temporary water) that is ideal for this species. Another factor that influences the beginning of the breeding season is when males position themselves near the surface water and begin to sing (more on this topic in behavior section).

The fertilized mother produces eggs and the number of eggs are around 200 or more. The eggs are laid in strings amid vegetation. Unlike the true toads (Bufo) these eggs lack the encased tubular gelatinous covering. Development of the eggs must by rapid because the breeding location has a rapid loss of water and the eggs must develop before the water disappears. The larval period may be as quick as 12 days and the maximum period may be up to 40 days.

The tadpoles of Scaphiopus holbrooki can be identified because spadefoots are the only species having a medial anus and a mouth that is not laterally infolded. The appearance of the tadpoles are flattened (meaning that the posterior end is wider than the anterior), bronze in color, and can reach a length of 28-mm (Dundee & Rossman, 1989).

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    730 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    730 days
    AnAge

Lifespan/Longevity

  • Average lifespan
    Status: captivity
    12.3 years
    AnAge

Behavior

The breeding behavior of the Eastern Spadefoot is described as an explosive breeder, meaning that the breeding season is quick, usually because of limiting factors that regulate breeding success (Punoz, 1992).

Once the males have reached the desired shallow pond, they begin to sing and attract receptive females. The number of males may reach up into the hundreds, all calling with their somewhat nasal voice. The voice has been described as an explosive 'waank' or 'waagh" in 3-4 second intervals (Dundee & Rossman, 1989). Others describe the call, which resembles a young crow (Conant & Collins, 1998).

Food Habits

The Eastern Spadefoot emerges from its burrow at night, usually the nights that are humid to prevent significant water loss. Once at the surface, the toad searches for worms and various arthropods (Dundee & Rossman, 1989). Thus, S. holbrooki would be considered a carnivore.

Economic Importance for Humans: Positive

There is no special economic importance.

Economic Importance for Humans: Negative

There is no special economic importance.

Conservation Status

No special status. They are quite a locally abundant species.

Contributors

Doug Byers (author), Michigan State University, James Harding (editor), Michigan State University.

Glossary

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.

ectothermic

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

metamorphosis

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.

motile

having the capacity to move from one place to another.

References

Conant, R., J. Collins. 1998. A Field Guide to Reptiles and Amphibians; Eatern and Central North America. New York: Houghton Mifflin Comp..

Dundde, H., D. Rossman. 1989. The Amphibians and Reptiles of Louisianna. Baton Rouge: Louisianna State University.

Oliver, J. 1955. The Natural History of North American Amphibians and Reptiles. Princeton, N.J.: D. Van Nostrand Comp..

Punzo, F. 1992. Dietary overlap and activity patterns in sympatric populations of Scaphiopus holbrooki.. Florida Scientist, 55: 38-44.