Frog legs with… claws?
Scientists have discovered that some African frogs have claws that burst through the skin of their toes much like those of Wolverine in X-Men. These frogs are the only vertebrates known to brandish claws in such a self-wounding manner. What's also surprising is that these claws are made of bone, rather than the hard protein called keratin that normally comprises fingernails, claws and hooves. Lead study author David Blackburn, a biologist from Harvard University, reports in Biology Letters that he had noticed that the flailing, kicking frogs left scratches on their antagonists' arms. He and other researchers then combed through museum frog specimens and discovered the bone-claws. Other scientists had mentioned their existence over the past century, but this is the first time it was confirmed. It appears, though, that Cameroon tribesmen were long aware of these amphibians' fierce secret weapon; they typically use long, nail-studded poles or machetes to lay blows to the frogs' heads when hunting to avoid getting slashed.