The fire-bellied toads or firebelly toads are a group of eight species of small frogs (most species typically no longer than 1.6 in or 4.1 cm) belonging to the genus Bombina. "Fire-bellied" is derived from the brightly coloured red- or yellow-and-black patterns on the toads' ventral regions, which act as aposematic coloration, a warning to predators of the toads' reputedly foul taste. The other parts of the toads' skins are green or dark brown. When confronted with a potential predator, these toads commonly engage in an Unkenreflex, "Unken-" being the combining form of "Unke", German for fire-bellied toad. In the Unkenreflex, the toad arches its back, raising its front and back legs to display the aposematic coloration of its ventral side.