WASHINGTON - At least 11 species of African frogs carry a built-in concealed weapon — they can sprout claws on demand to fight off attackers, U.S. researchers reported on Monday.

When threatened, the frogs can puncture their own skin with sharp bones in their toes that they then use to claw their attackers, David Blackburn and colleagues at Harvard University reported.

"It's surprising enough to find a frog with claws," Blackburn, a graduate student, said in a statement....................... more @ the link