The black (or plain) rain frog just has a permanently grouchy expression. And while remarkable, that frown is only one of this nocturnal amphibian’s unique adaptations. Here’s another: It’s fossorial, meaning it spends most of its life in burrows underground, where it absorbs moisture directly from the soil.
The frog’s shape is an effective defense mechanism: When faced with a threat, it puffs up with air like a balloon, expanding to several times its size. In addition to making the frog appear more intimidating, this extra girth helps the frog lodge itself in its tunnel, making it difficult for predators to pull it out.
During their summer breeding season, black rain frogs can be heard in large choruses that may last several days in rainy weather—perhaps why the Breviceps genus is thought by local people to signal impending rain. Unlike most frog species, these frogs don’t require access to open water to lay eggs or reproduce. Instead, females lay their eggs in shallow nests underground, which males guard until the embryos hatch—not as tadpoles, but as tiny, fully formed froglets.
