evidence: - Porcupine quills have antibiotic properties, as porcupines sometimes "quill" themselves. - Porcupines do not throw their quills. [...] Porcupines can be injurious to commercial forests and reforestation projects by feeding on the terminal buds or eating the bark all the way around the trees. When such problems occur, site specific control may be necessary, although within most of Alaska porcupines are not numerous enough to do much damage.