Tomato frogs are a sub-family of narrow-mouth frogs native to Madagascar. Three different species of tomato frog live on the island, though here we will focus on Dyscophus antongilii, also known as the Madagascar Tomato Frog or the Sangongon in the native Malagasy language. The species exhibits significant gender dimorphism, with females growing up to 10.5 cm (4.1 inches) long while the males only reach 6.5 cm (2.5 inches) (tomato frogs love a short king). Females also sport the more classic ketchup bottle red, while the males tend to be more of a Taco Bell mild sauce orange. Madagascar tomato frogs are opportunistic predators, gobbling up arthropods and other small invertebrates they happen to come across on the rainforest floor.
These funky-looking frogs have a particularly-unique method of deterring predators. When threatened, Madagascar tomato frogs release a milky white secretion from their bodies that behaves like a glue. This secretion is so sticky that it can disable predators, gumming up their mouths and hands or even gluing snakes to solid surfaces, allowing the frog to escape. Being covered in glue sucks (as anyone who was left unattended with a bottle of Elmer's as a child can attest to) so the bright colors on a Madagascar tomato frog warn predators that messing with it will result in a goopy demise. This kind of bright warning is called aposematic coloration, and it occurs all over the animal kingdom, from frogs to caterpillars to octopi. If the warning coloration and glue doesn’t deter a predator, Madagascar tomato frogs can inflate their bodies, making them larger and more difficult for a predator to swallow.
Madagascar tomato frogs represent a major success for species conservation. While listed as Near Threatened by the International Union for the Conservation of Nature (IUCN) as recently as 2008, wild populations have stabilized and the species is no longer considered at risk of extinction. This has to do partially with the species’ surprising adaptability to human settlement and partially with successful conservation programs. Madagascar tomato frogs have little problem surviving in urban biomes and can breed successfully in man-made ponds and ditches. Human gardens, meanwhile, make excellent habitats for them, allowing these frogs to thrive even in cities.
In the past, Madagascar tomato frog populations declined due to their value in the pet trade: the frog’s bright color made it popular among hobbyist pet owners, so poachers would capture them out of the wild and sell them worldwide. In response to this, researchers at several zoos, including my hometown Maryland Zoo in Baltimore, developed methods for breeding Madagascar tomato frogs in captivity. The species was also listed under the Convention on International Trade in Endangered Species (CITES), which regulates the export of exotic species in an effort to prevent wildlife trafficking. These two efforts combined have taken much of the pressure off of wild Madagascar tomato frog populations while also allowing responsible pet owners to keep these adorable little meatballs guilt-free.
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Sources and More Information:
IUCN SSC Amphibian Specialist Group. 2017. Dyscophus antongilii. The IUCN Red List of Threatened Species 2017: e.T6937A84159360.
Rudolph, A. 2017. Dyscophus antongilii. Animal Diversity Web, University of Michigan Museum of Zoology.
Smithsonian's National Zoo and Conservation Biology Institute, ND. Tomato Frog
Vences et al., 2018. Dyscophus antongilii. Amphibiaweb, University of California, Berkeley