Study
Microstructured barbs on the North American porcupine quill enable easy tissue penetration and difficult removal
Cho, Woo Kyung; Ankrum, James A.; Guo, Dagang; Chester, Shawn A.; Yang, Seung Yun; Kashyap, Anurag; Karp, Jeffrey M.
Proceedings of the National Academy of Sciences, 2012
Measured the force required to drive porcupine quills into tissue and to withdraw them, comparing natural barbed quills against quills whose barbs had been removed, and against synthetic replicas.
- Studied in
- Erethizon dorsatum
- Sample size
- quills tested for penetration and removal force, with and without barbs
The backward-facing barbs reduce the force needed to penetrate tissue — by concentrating stress at the barb tips — while substantially increasing the force needed to withdraw the quill. Barbed quills entered more easily and resisted removal far more strongly than debarbed ones.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
The barb microstructure independently optimises two opposed requirements: easy entry and difficult removal.
How NatureHQ reads it
The mechanism that explains why quills end up embedded in an attacker without anything being thrown. They are loosely attached to the porcupine and strongly attached to whatever they enter, so contact transfers them — which is the entire basis of the shooting myth.
- Force measurements in tissue analogues and animal tissue rather than in a live predator encounter.
- North American porcupine quills specifically; Old World porcupines have differently structured quills, many without barbs.
Measuring what a quill barb actually does
Porcupine quills carry microscopic barbs. Do they make the quill harder to remove, harder to insert, or both?
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Published by: Proceedings of the National Academy of SciencesPublished in PNAS.
doi.org/10.1073/pnas.1216441109
Checked against Crossref on 2026-09-28, and they agree on the title, the authors and the year.
NatureHQ summarises research in its own words and does not reproduce published text. Reviewed 2026-09-03.