Classification and Range
The smooth-sided toad belongs in the order Anura (frogs and toads) and in the family Bufonidae of “true toads.” Debate continues over its classification in the large genus Bufo, with more than 280 species; or if it belongs in the small sub-genus Rhaebo, which contains eight Latin American toads. Bufo toads are native to most continents, except for arctic regions; they have also been introduced in Australia. This species’ geographic range covers the huge Amazonian drainage area of South America with parts of Brazil, Bolivia, Peru, Ecuador, Colombia, Venezuela, Guyana, Suriname and French Guiana. It lives at elevations from 164 – 2,822 feet (50 – 860 m) above sea level.
All members of the Bufonidae family share stereotypic characteristics common to “true toads.” They have heavy, stocky bodies with short forelimbs and hind limbs that make them poor jumpers. They have horizontal pupils and lack teeth or tails. Their skins are dry and warty. Bufo guttatus is relatively smooth (as its name implies), with only a few flat and dark warts. Its upper head and back are light brown with a dark brown band along the sides of both head and back. The red-brown throat and belly have cream-colored spots.
Smooth-sided toads inhabit subtropical and tropical regions of rainforests under leaf litter and in wetland areas with rivers, streams, waterfalls, freshwater marshes and pools. They prefer microhabitats of small rock piles.
Size and Weight
Males are usually smaller and may have darker throat coloration. Females grow up to 10 inches (25 cm) in length while males reach 5 – 6 inches (13 – 15 cm).
Up to 10 years in captivity. Life expectancy in the wild is probably shorter.
In the wild: insects, other small invertebrates and small mammals.
At the zoo: crickets and bloodworms.
The smooth-sided toad breeds in the presence of water. Males grasp the female while transferring sperm to the eggs. She lays up to 10,000 eggs a few hours after mating. Egg development requires warm temperature of at least 75° Fahrenheit (24° C). If there are too many eggs, a “crowding-effect” occurs and some of the embryos die. Tadpoles hatch after seven days. After six weeks as tadpoles, they complete metamorphosis and become juvenile toads. Both embryonic and larval stages occur in water.
Don’t touch that toad!
Bufo toads secret a type of venom from the bulbous parotoid glands behind their eyes. This fatty, white substance called “bufotoxin” deters predators from eating them. The venom of the Bufo alvarius could cause heart failure if swallowed. Toads can also inflate their bodies as an additional form of defense. However, contrary to common myth, touching toads does not cause warts.
Toad or Frog – how to tell?
To start with, all toads are frogs. However “true toads” have squat bodies, short limbs, dry “warty” skin, no teeth and poison glands. In contrast, frogs have a longer, slender body; longer limbs for jumping and webbed feet for swimming; smooth, wet-looking skin; teeth in their upper jaws; plus large ears and a longer, pointed snout. The word toad is often used for other frogs and the terms can be misleading. .
Location at the Zoo
Woodland Park Zoo's smooth-sided toads are on display in the Day Exhibit. The zoo also keeps a number of other amphibian species on or off exhibit. Other species of amphibians can be seen in the Day Exhibit, the award-winning Tropical Rain Forest and Zoomazium. They include the axolotls, poison dart frogs, Panamanian golden frogs and the African gray tree frogs.
Smooth-sided toads are not an endangered species. However, at least 40 other species of frogs in the genus Bufo are either endangered or critically endangered. Smooth-sided toads have a very large range and threats to their survival are mostly local. The biggest threat to the survival of amphibians is loss of habitat from human–caused activities. These activities include drainage of wetlands for agriculture, housing, logging and construction of roads. Frogs and toads are particularly vulnerable, since humans often develop the land next to lakes, rivers and streams where these animals come to lay their eggs. Due to their inability to tolerate habitat alteration, most amphibians cannot maintain sustainable levels with the presence of these threats. Pollution, climate change and invasive species introduced by humans also take their toll on local amphibian populations.
Over the past 50 years, scientists have recorded major declines in frog populations around the world. A few species have vanished completely. Scientists continue to search for answers, as a newly-discovered fungal disease (Batrachochytrium dendrobatidis – aka chytridiomycete) presents the most potent natural threat. In 1999, researchers identified this fungus as responsible for massive extinctions of wild amphibians worldwide. Researchers believe that chytridiomycosis kills by suffocation and disruption of thermoregulation. Chytrid fungus spreads rapidly and apparently does not easily disappear from the environment, even after all the former amphibians die. Cures for it exist; however, it is not practical for those in the wild due to likely re-infection. Unraveling the mysterious decline in frogs has become the focus of a worldwide effort among scientists and conservationists.
In 2005, participants from the Amphibian Conservation Summit created an action plan (see: http://www.amphibians.org/) to stop the global decline in amphibians. Additionally, scientists at the Smithsonian National Zoo and the National Museum of Natural History hope that zoos can harbor populations near the brink of extinction and establish insurance populations for future re-introduction. In order for this plan to succeed, zoos must provide adequate capacity for breeding or housing, while receiving long-term funding. Participating institutions could also pursue research activities including improvements in husbandry practices, disease monitoring and treatment, captive breeding and establishment of genome resource banks. Although smooth-sided toads occasionally show up in the international pet trade, they occur at levels that are not significant to their survival in the wild. However, the increasing demand of the pet trade lowers numbers of many amphibian populations to the point where they may become extinct in the wild.
Every year, many more wild-caught animals die than ever reach pet stores. Those that survive are often stressed, malnourished and untamable. In recent years, humans have heavily imported many species of frogs and toads as increasing numbers of pet store owners want to sell them. One way to decrease demand for importation of reptiles is for potential owners to demand captive-born individuals.
Amphibians as Pets
Since amphibians and reptiles require very specialized diets and environments, Woodland Park Zoo (WPZ) does not recommend them as pets for most people. WPZ also receives hundreds of requests each year to take former pet toads, frogs and other amphibians but we cannot accept these due to space, health and unknown backgrounds. If you need to find a reptile or amphibian a new home, we suggest you contact a local herpetological group in your area.
In the Puget Sound region, it is the Pacific Northwest Herpetological Society. Anyone interested in owning a reptile or amphibian should learn about its needs and be sure it was captive-bred. Read more about keeping a reptile by visiting: http://www.kingsnake.com/ballpythonguide/pets.htm.
How You Can Help!
The effort to save endangered species like the tomato frog requires cooperation and support at the international, national, regional and individual levels. You can help in this cause. Join and become active in Woodland Park Zoo and other conservation organizations of your choice. Don't buy products made from wild animal parts. Contact your elected representatives and express your views about conservation of endangered species and wild habitats.
Contact Woodland Park Zoo at firstname.lastname@example.org to find out other ways you can support conservation programs at the zoo. Discover more about smooth-sided toads by contacting the Society for the Study of Amphibians and Reptiles at http://www.ssarherps.org, or the American Federation of Herpetoculture: AFH, PO Box 300067, Escondido, CA 92030-0067. Find other groups and information online at http://www.parcplace.org, the website of Partners in Amphibian and Reptile Conservation, or by searching the keyword "herpetology." Learn other ways you can help conserve wildlife and the habitats they require for survival by visiting our How You Can Help page.
Reptiles as Pets
We do not recommend reptiles as pets for most people as they require very specialized diets and environments. We also receive hundreds of requests each year to take former pet iguanas, boas and other reptiles but we cannot accept these due to space, health and unknown backgrounds. If you need to find a reptile or amphibian a new home, we suggest you contact a local herpetological group in your area.
In the Puget Sound region, contact the Pacific Northwest Herpetological Society as a resource. If you do choose to get a reptile as a pet, please learn as much as possible about their care and the best species before making your decision and never accept wild-caught animals as pets or release non-native reptiles or amphibians into the wild.
Sources and Suggested Reading
AmphibiaWeb: Information on amphibian biology and conservation. 2008. Accessed July 3, 2008 at http://www.amphibiaweb.org
Cogger, Harold G. and Richard G. Zweifel, editors. 1998. Encyclopedia of Reptiles and Amphibians, 2nd edition. Academic Press, San Diego. 240 p.
Duellman, William E. and Linda Trueb. 1994. Biology of Amphibians. Johns Hopkins University Press, Baltimore, MD. 696 p.
IUCN, Conservation International and NatureServe. Bufo guttatus. 2006. Global Amphibian Assessment (GAA). Accessed July 15, 2008 at http://www.globalamphibians.org/servlet/GAA?searchName=Bufo+guttatus
Pough, F. Harvey, Robin M. Andrews, John E. Cadle, Martha L. Crump, Alan H. Savitzky and Kentwood D. Wells. 2003. Herpetology, 3rd edition. Benjamin Cummings Press, San Francisco, CA. 736 p.
Smithsonian National Zoological Park: Conservation & Science: Spotlight on Zoo Science. 2006. Accessed July 3, 2008 Toadily Toads FAQ. Accessed July 3, 2008 at http://www.toadilytoads.com/toadilytoads_faqs.html
Wikipedia, the free encyclopedia: “Bufo.” 2008. Accessed July 3, 2008 at http://en.wikipedia.org/wiki/Bufo
World Association of Zoos and Aquariums (WAZA). 2008. Accessed July 3, 2008 at http://www.waza.org
Zug, George R, Laurie J. Vitt and Janalee P. Caldwell. 2001. Herpetology: An Introductory Biology of Amphibians and Reptiles, 2nd edition. Academic Press, San Diego, CA. 630 p.