Amphibians
Tomato Frog
Dyscophus antongilii · also called Madagascar tomato frog, crapaud rouge
The tomato frog is exactly what it sounds like — a plump, round, brilliant-red frog from Madagascar that really does look like a ripe tomato sitting in the leaf litter. The colour is a warning, and the frog backs it up with a puff-up display and a mouthful of glue for anything that tries to eat it.
Overview
Tomato frogs live in a small area of northeastern Madagascar, around Antongil Bay, in lowland rainforest, swamp forest, and the disturbed edges of both — including drainage ditches, garden pools, rice-field margins, and slow streams near the town of Maroantsetra. They are mostly nocturnal and terrestrial, spending the day partly buried in soft ground or leaf litter and emerging at night to sit-and-wait for passing invertebrates.
Red for a reason
The bright tomato-red of adult females (males are smaller and a duller yellow-orange) is aposematic — a signal to predators that the frog is not worth eating. When a snake, bird, or mammal ignores the warning and grabs one, two defences kick in:
- Inflation. The frog swallows air and blows itself up into a rigid ball, raising its body on stiff legs, becoming much harder to bite or swallow.
- The glue. Glands across the skin release a thick, white, extremely sticky secretion that clogs the predator’s mouth, throat, and eyes and can cause a burning irritation. In humans it can produce an allergic skin or eye reaction. It is not a lethal poison, but it makes the frog a thoroughly unpleasant mouthful.
Reproduction
Breeding is explosive, triggered by heavy rain. Males gather at temporary and permanent pools and give a low call; a female lays a large mass of 1,000 to 1,500 small black-and-white eggs on the surface of still, shallow water. The tadpoles are filter-feeders and complete metamorphosis in about six weeks, emerging as tiny yellowish froglets that redden as they mature.
Status
The tomato frog was formerly Near Threatened, reflecting its very small range and a history of heavy collection for the pet trade. International trade is now controlled under CITES and largely supplied by captive breeding, and the wild population has proved resilient — it readily uses human-modified water bodies — so it is currently assessed as Least Concern. It still depends on the swamp and forest habitat of the Antongil Bay region, and shares the broader threats facing Madagascar’s amphibians: deforestation, pollution, and disease.
Tomato Frog: common questions
Is the tomato frog poisonous?
It is not poisonous in the way a poison dart frog is — you would not be harmed by eating small amounts, and it does not carry a lethal toxin. Instead, when grabbed it secretes a thick, sticky white substance from glands all over its skin. This glue physically fouls a predator's mouth, throat, and eyes, making the frog very unpleasant to hold or swallow, and in people it can cause a burning irritation and, in some, an allergic skin or eye reaction. So it is better described as having a defensive, irritating glue than a poison.
Why does the tomato frog puff itself up?
It is a bluff. Threatened, the frog gulps air and inflates its already round body into a taut ball, lifts itself up on straight legs, and sometimes turns its most colourful side toward the threat. This makes it look far bigger and harder to bite or swallow, buys time, and shows off the warning colour. If the display fails and the predator bites down, the sticky skin secretion is the backup defence.
Why are only the female tomato frogs bright red?
Female tomato frogs are much larger than males and a vivid tomato-red, while males are smaller and a duller yellow-orange. The strong colour is mainly a warning signal (aposematism) advertising the frog's noxious skin secretion, and the size and brightness of females may also relate to their much greater investment in eggs — a big, conspicuous female that is also well defended can afford to be seen. Young frogs of both sexes are yellowish and become redder with age.
Are tomato frogs endangered?
Dyscophus antongilii was long listed as Near Threatened because it has a very small range in northeastern Madagascar and was heavily collected for the international pet trade in the past. Trade is now regulated under CITES and largely met by captive breeding, and the frog is currently assessed as Least Concern, remaining locally common — it even breeds in roadside ditches and town pools. Its restricted range still makes it vulnerable to habitat loss, water pollution, and the amphibian chytrid fungus.