Continuing with this series on animals at Northwest Trek Wildlife Park. You don't want to mess with porcupines, though they are slow moving herbivores that aren't naturally aggressive: "These nocturnal, mostly solitary mammals, best known for their sharp quills, go about the business of living and don't become aggressive unless threatened. To scare off predators, porcupines raise the 30,000 or more quills covering their bodies. Like human hair and avian feathers, quills are made of keratin. Quills are not fired from the rodent's body; predators coming too close get stuck with quills much the way humans get wood slivers or burrs from plants. Surprisingly, porcupine quills have antibiotic properties. Porcupines often fall from trees and impale themselves on their own quills. Scientists think the antibiotic-laced quills prevent infections from developing in these self-imposed wounds." Please zoom.