If you’ve ever had a violent encounter with a porcupine, it probably didn’t end well. The large rodents are most well-known for the coat of some 30,000 barbed quills that cover their backs, an evolutionary adaptation to protect against predators. Although they appear thin—even flimsy—once quills lodge in your flesh, they’re remarkably difficult and painful to get out.
Recently, a group of scientists led by Jeffrey Karp of Harvard decided to closely investigate just what makes these quills so effective. As they report in an article published today in the Proceedings of the National Academy of Sciences, their analysis revealed a specialized microscopic barbed structure that enables the quills to slide into tissue extremely easily but cling to it stubbornly once it’s in place.