Tomato Frog
(Dyscophus antongilli)
Endangered Species

Classification and Range
The tomato frog belongs to the family Microhylidae, the family of “narrow-mouthed frogs,” and together with the two other species in the genus Dyscophus, make up the subfamily Dyscophinae. There are about 270 species of microhylid frogs, most of them living in tropical habitats around the world. Most have no teeth, but instead have ridges of folds on the roofs of their mouths. Only three species of microhylids are found in the United States. (continued below)
Range Map

 
 

Classification and Range
The tomato frog comes from the huge island of Madagascar, off the east coast of Africa, where during more than 40 million years of isolation many species have evolved which occur nowhere else. Tomato frogs are found on the northeast coast of Madagascar, mainly around Antongill Bay, from which the frogs take their scientific name.

Habitat
The areas in which tomato frogs occur are almost uniformly warm throughout the year, with temperatures between 76°and 90° F (25°-30° C). It rains frequently as well, and there is really no dry season to speak of. The forest in this part of Madagascar is made up mainly of Pandanus palms, but tomato frogs do not live in primary forest, and are often found in ditches and ponds near farms and towns.
Size and Weight
Adult male tomato frogs are about 2.5 inches (65 mm), weigh around 1.5 ounces (40 gr) and are orange or brown-orange in color. A female tomato frog is bright red, measures more than 4 inches (10.1 cm) in length, (nearly twice the length of a typical male) and weighs about 8 ounces (227 gr). Female tomato frogs really do resemble ripe tomatoes.
Life Span
10 years (estimate) in the wild. Many frogs can live for more than 10 years, and it is probable that some tomato frogs live into their teens.

Diet
In the wild: Arthropods and other animals which catch their attention, are small enough to eat and unwary enough to come near these ambush-feeding frogs.

At the zoo: Vitamin-dusted crickets and mealworms.

Reproduction
In areas where they occur, male tomato frogs are often heard calling from ditches, marshes and shallow pools after rains, summoning females to breed. In captivity, tomato frogs breed when they are subjected to an artificial “rain” following a dry period. Each female lays 1000-1500 eggs, which float on the surface of the water.

Life Cycle
Quarter-inch-long (6 mm) tadpoles hatch 36 hours after the eggs are laid, and are “filter-feeders,” straining tiny bits of nutrients from the water in order to get everything they need to grow and develop. In captivity they metamorphose into tiny froglets about 45 days after hatching. They reach adult size and are probably sexually mature in less than a year.

They Look Delicious, But Don't Eat 'em
Why are tomato frogs so brightly colored? They secrete a toxin from their skin as a form of defense, and humans who have eaten tomato frogs have suffered severe allergy-like symptoms. Other frogs, like poison dart frogs, are brightly colored to warn predators that they are not good to eat. These warnings are called “flash” colors or aposematic coloration, and it may be that the tomato frogs are advertising their toxicity.

Fascinating Facts

  • When a frog closes its eyes, it is the eyes that move; they are pulled down into the head by the action of muscles in the skull!
  • Very few frogs are salt water tolerant; a few can live in brackish water. This is an indication that while life may have come from the sea, land-dwelling vertebrates, which are descendants of ancient amphibians, arrived there by way of fresh water!

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Tomato frogs are on exhibit in the Day Exhibit. They share their home with a captive-bred example of a rare species of lizard—Standing’s day gecko, which is also found on Madagascar. Standing’s day geckos are disappearing because of the pet trade and because the dry thorn forests of southwestern Madagascar are being cut down for charcoal.

Other species of frogs which can be seen in the Day Exhibit are: waxy treefrogs, Solomon Islands leaf frogs, ornate horned frogs and blue and yellow poison dart frogs.

The tomato frog is an endangered species.* Tomato frogs are fortunate in that they do not depend on primary forest, little of which remains in Madagascar is disappearing fast. Sometimes breeding in areas of human disturbance and activity, they are vulnerable to collection for the illegal animal trade and from the increasing runoff of pesticides, herbicides and detergents into the ponds and ditches where they often breed. Their distinctive call also makes them identifiable even in the darkness of the Malagasy night, so that poachers may pick them like (yes, indeed) so many ripe tomatoes.

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 webkeeper@zoo.org to find out other ways you can support conservation programs at the zoo. Discover more about frogs by contacting the Society for the Study of Amphibians and Reptiles at 303 W. 39th St., PO Box 626, Hays, KS 67601. 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
Glaw & Vences. 1992. Amphibians and Reptiles of Madagascar. Published by the authors, Cologne, Germany. 331 p.

Preston, Mafbam. 1991. Madagascar, a Natural History. Facts on File, New York, NY. 224 p.

For Kids!
Fichter, George S. 1993. Turtles, Toads and Frogs. A Golden Book, New York, NY. 36 p.

Pallotta, Jerry. 1990. The Frog Alphabet Book. Charlesbridge Publishing, Watertown, MA. 30 p.

* Woodland Park Zoo identifies an animal or plant endangered if it is listed as endangered (in any part of its range) on the federal list of Endangered and Threatened Wildlife and Plants, or if it is listed on Appendix I to the Convention on International Trade in Endangered Species (CITES).