Barbs make porcupine quills into nasty needles : Nature News & Comment

What animals can kill porcupines and how do they do it? How can they get past the quills? - Quora

How porcupine quills work : r/Damnthatsinteresting

Honey badger versus porcupine, unsure of porcupine's condition : r/natureismetal

Porcupine Quills Reveal Their Prickly Secrets, Science

Microstructured barbs on the North American porcupine quill enable easy tissue penetration and difficult removal

porcupine wondermyway

Adirondack Wildlife: The Porcupine Gives Birth - - The Adirondack Almanack

Barbs make porcupine quills into nasty needles : Nature News & Comment

Alaska Magazine Beware the Spiny Pig

Why A Snoot-full Of Porcupine Quills Can Be A Serious Matter – Feathered Photography