Tiny and spiny, hedgehogs still roam their native territories of Europe and Asia. Their omnivorous—though lactose-intolerant—nature allows for a variety of habitats, but hedgehogs prefer nocturnal burrowing and seeking sheltered spots underneath piles of leaves. Their quills, the prominent feature of the minuscule body, are primarily filled with air spaces; the spines seem ferocious, in order to ward off potential predators. Another quilled mammal, the porcupine, is a rodent and therefore not intimately related to the hedgehog: moles and shrews are the hedgehog's closer cousins.
Torpy JM. A Hedgehog. JAMA. 2009;301(24):2531. doi:10.1001/jama.2009.645