The horror frog, more commonly called the hairy frog (Trichobatrachus robustus), gets its ghastly nickname because of a novel trait not unlike that of the villain in a slasher movie: When threatened, the frog deliberately breaks bones that protrude like claws through the skin of the feet. This gruesome method of defense is not totally unheard of among amphibians -- some salamanders' ribs can do something similar -- but the horror frog takes it to a new level.
The Bone Breaking
The hind feet of hairy frogs contain claws that are made entirely of bone and that are usually unseen beneath the skin. A muscle connected to each bony claw can contract, breaking it off and pushing the claw through the skin. Because hairy frogs have not been studied much when alive, it is not certain whether the frog can deliberately retract its claws later or whether they just slide back inside after use. It is likely that the broken and damaged tissue regenerates.
Other Physical Characteristics
Adding to the frog’s bizarre appearance is hair, or actually hairlike strands of skin that the males produce around their legs and backs during the breeding season, possibly to help them absorb more oxygen. The species has small lungs, and the hairlike strands give him more capacity to copulate when this froggie goes a' courtin'. The similarity to a monster from a horror film pretty much ends here -- the hairy frog reaches just 4 inches long; only flies are likely to see the animal as a terrifying monster.
Habitat and Ecology
Hairy frogs are found in western Africa, from Nigeria down to the Democratic Republic of Congo, where they live in and alongside fast rivers within lowland rainforests and farmland. Both the tadpoles and the adults are carnivores, eating small invertebrates.
The International Union for Conservation of Nature and Natural Resources lists the hairy frog as of “least concern” on its Red List of Threatened Species, but the creature's numbers are decreasing. Horror frogs won't have to hide from resolute crusaders armed to the teeth with garlic and holy water, but they do face serious threats. Both tadpoles and adult hairy frogs are hunted for food; habitat alteration doesn’t appear to be a major problem, but water pollution is. The species has become locally rare in some places.