Tomato Frog
Tagged: animal, animals, cat, invertebrate, petsDyscophus antongilii
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The red or orange-colored tomato frog of Madagascar has been threatened by habitat destruction, pollution, and overcollection for the pet trade. It is now protected and responding well to captive-breeding programs. The tomato frog gets its name from the rounded shape of the female and her red coloration, which makes her resemble a ripe tomato. Not all tomato frogs are red; some are orange, others dark brown, and males are generally less vividly colored than females. The frog has a flat head, a rounded body, and white underside; females are considerably larger than males. Their striking coloration, combined with the fact that they thrive in captivity, have made them popular animals in the international pet trade. Found only in Madagascar, the tomato frog has a small range. It occurs in two main areas on the coastal plain in the northeast of the island. Its preferred habitat is soft soil, where standing water for it to breed in accumulates during the rainy season. A secretive, nocturnal animal, it hides during the day, emerging at night to hunt ground-dwelling invertebrates. The frog’s round shape and lack of adhesive disks on its fingers and toes mean that it is unable to climb. Nor is it particularly well adapted for swimming, having only partial webbing between its toes and none between its fingers. During the dry season it burrows deep into sandy soil, using horny protuberances on its hind feet.
Sticky Defense
In many amphibians bright coloration is associated with skin toxins that make them unpalatable or poisonous to potential predators. The tomato frog’s bright color serves to warn predators that it is not good to eat. When attacked or handled, it secretes copious amounts of sticky mucus from its skin; any animal trying to eat it is likely to find its jaws glued together. A number of amphibians have this kind of defense, but the tomato frog produces mucus with stronger sticking power than that of any other frog. It is also mildly toxic, often causing an allergic reaction in humans.
Breeding after Rain
With the first indication of rain male tomato frogs emerge from underground and head for ditches, ponds, and pools as they fill with water. It is thought that the sound of rain falling on the ground is a sufficient stimulus to bring males out of hiding. Males call to attract females from the edge of the water, inflating a single vocal patch under the chin. Females lay between 1,000 and 1,500 eggs that float on the surface of the water. Filter-feeding tadpoles hatch from the eggs within two days and take a further six weeks to metamorphose into juvenile froglets. The young frogs are about 0.4 inches (1 cm) long by this stage and black or brown with a tan stripe down the back. They develop the characteristic adult colors at about three months and are fully mature by one year.
Threats and Conservation
The tomato frog has a restricted range in Madagascar, and much of its natural habitat has been destroyed to make way for building and agricultural land. This has not been as disastrous for the tomato frog as for other species, since they thrive alongside human activities and habitations. Large breeding populations form in man-made drainage ditches, rice fields, and flooded meadows, but these habitats are susceptible to pollution from pesticides, herbicides, and detergents. The main threat to the tomato frog comes from the worldwide trade in amphibians. Large numbers used to be exported from Madagascar to Europe and the United States. Although it is nocturnal, the frog’s distinctive nighttime call made it possible for poachers to identify and capture it in the dark. The trade in tomato frogs for pets has now been stopped. The species is fully protected under CITES and breeding successfully in captivity, although lack of genetic diversity is a problem. To help increase diversity, attempts will be made to crossbreed frogs from European and American collections. The aim is also to build up captive populations in Madagascar for export to foreign breeding programs. The pet-trade market could then be met by captive-bred, rather than wild-caught frogs, and captive-bred animals could be used to reestablish populations in the wild.
Tomato frog
Dyscophus antongilii
- Family: Microhylidae
- World population: Unknown
- Distribution: Eastern coastal plains of Madagascar
- Habitat: Lowland habitats with soft soil; some agricultural areas
- Size: Length: male 2.5 in (6.5 cm); female 3.3-4.8 in (8-12 cm)
- Form: Flat head, plump body, partial webbing between toes. Female bright red, occasionally orange or dark brown on the back; belly white. Male has duller, yellow-orange coloration
- Diet: Small invertebrates
- Breeding: 1,000-1,500 black and white eggs laid on water surface; tadpoles hatch within 36 hours; metamorphosis complete at 6.5 weeks; fully mature at 12 months. Life span 10 years
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