More Information

Additional Information

Scaphiopus couchiiCouch's Spadefoot

By Shauna Alexander

Geographic Range

This species is found in the southwestern United States, extending into Mexico (and including the Baja Peninsula).

Habitat

Scaphiopus couchii lives underground in burrows in grassland prairies and mequite savannas. They dig these burrows in soft earth by backing into the ground and digging with hind feet, which are armed with spades. They rock the body as they dig; dirt falls into the burrows on top of the toads. Scaphiopus couchii seeks shelter under fallen logs and is adapted to arid and semi-arid conditions.

Physical Description

Scaphiopus couchii has a stout body and is 2.25 to 3.5 inches (5.6 to 8.8 cm). The color varies from bright green-yellow to brown-yellow. The dorsal surface is mottled with dark green, brown, or black markings, and the dark markings are more extensive in females. The ventral surface is white. The skin is covered with many small warts. The hind limbs have a single, sickle-shaped tubercle, or spade on the inner surface. The pupils are vertical in bright light.

  • Sexual Dimorphism
  • sexes colored or patterned differently
  • Range length
    2.25 to 3.5 mm
    0.09 to 0.14 in

Development

Reproduction

Scaphiopus couchii (like other frogs and toads) breeds only during the warmer seasons of the year. Breeding takes place from April to September, usually in temporary rain pools or temporary overflow areas. When their eggs are mature, the females enter the water and are clasped by the males in a process called amplexus. As the female lays the eggs, the male discharges seminal fluid containing sperm over the eggs to fertilize them. The jelly layers absorb water and swell after fertilization. The eggs are laid in large masses, usually anchored to grass or plant stems. Eggs hatch within 36 hours and the tadpoles develop quickly. After the tadpole has undergone metamorphosis (30 to 40 days after the eggs have hatched), the adult S. couchii is ready to reproduce.

  • Breeding season
    Breeding takes place from April to September

There is no parental investment after egg-laying.

  • Parental Investment
  • pre-fertilization
    • provisioning

Lifespan/Longevity

  • Average lifespan
    Status: captivity
    6.7 years
    AnAge

Behavior

Scaphiopus couchii is nocturnal and active during rainy conditions. It burrows deeply underground, digging backwards using its hind feet. This burrowing is a remarkable adaptation to the extreme environments (the hottest, driest regions) in which they live. One of the first drives after the dormant period is breeding. In the spring males croak to attract females, calling from the rims of temporary pools. Large choruses can be heard from great distances. It is a harsh and noisy lamb- or goat-like bleat lasting 1/2- 1 second. The individual call is: "wow, me ow" or "a ow"

Communication and Perception

In the spring males croak to attract females, calling from the rims of temporary pools.

Food Habits

Scaphiopus couchii eats mostly insects. Scaphiopus couchii survives ten months of hibernation (during which it does not feed) by utilizing stored lipid reserves predominantly concentrated in coelomic fat bodies.

  • Animal Foods
  • insects

Predation

Adults of the parasite Pseudodiplorchis americanus infect breeding toads and feed on the host blood during hibernation. Infected toads that emerge from hibernation have smaller fat bodies than those that are uninfected. Fat body weights increase, however, during a period of foraging; there is no measurable effect after two weeks of feeding. A case study by Tocque has suggested that some toads might not breed or survive hibernation due to this parasitic infection. Therefore, there is potential for these parasites to regulate host populations.

Ecosystem Roles

Scaphiopus couchii is a significant predator in its ecosystem, keeping many kinds of insects (that bother humans) under control.

Economic Importance for Humans: Positive

Scaphiopus couchii is a significant predator in its ecosystem, keeping many kinds of insects (that bother humans) under control. While S. couchii may not be the typical "laboratory frog", it certainly has research value for the scientific community, especially in the areas of development and adaptations (such as burrowing). Most importantly, S. couchii constitutes a part of the remaining wild animal life of the world and should be appreciated in terms of biodiversity.

  • Positive Impacts
  • research and education
  • controls pest population

Economic Importance for Humans: Negative

The burrows may make land unsuitable for developing and cultivation purposes.

Conservation Status

Because of the life cycles of Scaphiopus couchii (both aquatic and terrestrial stages), the thin, permeable skin and the underground dwelling, this species is especially sensitive to environmental perturbations. Such environmental problems may include acid rain, increasing ultraviolet irradiation, changes in land and water, and other factors. As always, humans must begin taking greater resonsibility for the world around them.

Other Comments

A case study by Tinsley and Tocque has suggested that population dynamics of S. couchii in the desert are governed by the duration and intensity of summer rainfall, the effects of which are recognizable in the growth records of individuals (by analysis of growth rings from bones) and in the age-structure of breeding populations.

Contributors

Shauna Alexander (author), University of Michigan-Ann Arbor.

Glossary

acoustic

uses sound to communicate

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.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

choruses

to jointly display, usually with sounds, at the same time as two or more other individuals of the same or different species

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

ectothermic

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

external fertilization

fertilization takes place outside the female's body

fertilization

union of egg and spermatozoan

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

hibernation

the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

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.

nocturnal

active during the night

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

radial symmetry

a form of body symmetry in which the parts of an animal are arranged concentrically around a central oral/aboral axis and more than one imaginary plane through this axis results in halves that are mirror-images of each other. Examples are cnidarians (Phylum Cnidaria, jellyfish, anemones, and corals).

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

terrestrial

Living on the ground.

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.

savanna

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.

visual

uses sight to communicate

References

Academic American Encyclopedia, Volume 8. Grolier, Danbury, 1996.

Backstanz, L. http://www.zo.utexas.edu/research/txherps/frogs/scaphiopus.couchii.html

Hickman, Cleveland and Roberts, Larry. 1995. Animal Diversity, Wm. C. Brown Publishers, 1995.

Tinsley and Tocque, 1995. The population dynamics of a desert anuran, Scaphiopus couchii. Australian Journal of Ecology 20(3), 376-384.

Tocque, K. 1993. The relationship between parasite burden and host resources in desert toad (Scaphiopus couchii) under natural environmental conditions. Journal of Animal Ecology 62(4), 683-693.

Wright, Albert and Anna Wright. 1995. Handbook of Frogs and Toads of the United States and Canada, Comstock Publishing Company, Inc., United States of America.

Search

Navigation Links

Information
Pictures
Classification

Classification