Fire-Bellied Toads and Barbourulas: Bombinatoridae

The fire-bellied toads are best known for the rather unusual way they defend themselves. The frogs have glands in the warts down their backs that can release a bad-tasting, white and foamy ooze that is also slightly poisonous. When the frog feels threatened, possibly by a predator that comes too close, it flips over, arches its back, stretches out its back legs, and reaches its forelegs up. Sometimes, the frog stays on its belly, but arches its back and spreads its legs. Both of these unusual displays show off the frog's bright red, orange, or yellow underside to the predator. Scientists call this odd back bend an unken (OONK-en) reflex. The unken reflex and the colors it displays remind the predator that this frog does not make a good snack. Despite the frog's best efforts, the defense tactic is not always successful, and many of these frogs become meals for attackers. For example, a shorebird known as a night heron may get as much as one-quarter of its diet from fire-bellied toads.

The two main types of frogs in this family—the fire-bellied toads and the barbourulas—lead very different lives. The fire-bellied toads are very active during the day, often hopping about on land in open areas, like meadows. Compared to the fire-bellied toads, the barbourulas are very shy. These frogs stay out of sight, usually hiding among rocks in the water. When barbourulas do wander onto land, their gray and brown backs help them blend into the colors of this habitat, too. This camouflage, their secretive behavior, and the small numbers of this species that exist have made barbourulas difficult to study, and scientists still know little about them.

The mating season for many of the fire-bellied toads starts in late spring and continues into the middle of summer, and some may breed two or three times a year. Unlike the males of other types of frogs, which call only during certain times of the day, male fire-bellied frogs sing at any time, even though they only mate with the females in the evening hours. Males mate with females by grabbing onto their back so they look as if they are riding them piggyback. This puts the male in the right position to fertilize (FUR-teh-lyze) her eggs as she releases them. During the mating season, a male will sometimes mistakenly grab onto a second male instead of a female. The second male frantically tries to squirm away, sometimes making a croaking squeal, known as a release call. People sometimes use this mating behavior as a quick way to tell the males from the females: During the mating season, those toads that climb onto the backs of others are likely to be males, and those who do not try to squirm away when another grips them are likely females. Just because a toad tries to get away does not necessarily mean that it is a male, however, because females who are not ready to mate will also try to escape the clutch of a male toad.

Each female can lay up to 200 eggs a year, although many lay only a few to a couple of dozen at a time. She usually drops them in the water, either on underwater plants or down on the bottom. Some frogs lay their eggs in permanent bodies of water, like streams or ponds that never dry up, but others lay their eggs in temporary pools of water that disappear in dry summer months. In about a week, sometimes longer, the eggs hatch into tadpoles. In another six weeks or so, the tadpoles turn into baby frogs. The timing is very important to those that are born in temporary pools of water. If they cannot change into toadlets before the water disappears, they may dry up and die.

The female barbourula is a bit different than the fire-bellied toad. She lays her eggs— about 80 large eggs at a time—beneath underwater stones. Little more about this species's reproduction is known.