The world is home to about 4,740 species of frogs, one of which is the "horror frog." This frog, also known as the "hairy frog" (Trichobatrachus robustus), is native to Central Africa. What's unique about the horror frog is that, as the name suggests, it creates a sense of horror in predators by breaking its own bones to form claws through its skin.
When the horror frog feels threatened, its muscles contract and pull the bones inside its thumbs. The bones break at the tip, pierce through skin, and emerge from the underside of the thumbs. The bones are now essentially claws, and the horror frog is ready to defend itself. The horror frog is the first species of amphibian that scientists have come across that can make its bones pierce through skin on demand. What is yet to be understood is whether the horror frog's "claws" can retract into the thumbs.
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