NGM Blog Central - Escape Claws - National Geographic Magazine

Frog-claws-200 African frogs have taken a page right out of comic books. Like the X-Men character whose fists encase deadly blades, some frog species conceal tiny claws in their toes that cut through the animals’ own skin in order to wield them against a foe.

These amphibians have been digging into humans—and no doubt other predators—for years, but until now no one sought the cause. While collecting frogs in Cameroon, Harvard biologist David Blackburn became intrigued when one of them gave him a bloody scratch. Examining museum specimens, he’s so far found 11 species with wound-inflicting anatomy in their back feet. During stress-induced muscle contractions, he says, the sharp bony tips “pierce their way to functionality.”

Defenses that harm their user are rare, and how this one evolved isn’t yet known. But the damage done is likely minimal. “I suspect the skin heals fine,” Blackburn says. “Amphibians have remarkable regenerative capabilities.” —Jennifer S. Holland

Photo: The hairy frog is one species with bony claws that rip its own skin—a bizarre anatomical feature. Photograph by David C. Blackburn. Art: Mariel Furlong, NG staff

Posted by National Geographic Staff | Comments (0)
Filed Under: Wide Angle, Wildlife

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