Porcupines, known as the Cape Porcupines, are the largest rodents in Namibia. Their back is covered with long (12 inch/30 cm) black and white quills that can be raised as a defence mechanism against predators or when threatened, making the animal appear twice its size. These sharp quills can easily be dislodged when attacked by a predator and become embedded in the predator's face and claws. Additionally, porcupines intimidate approaching danger by making a rattling noise by shaking the hollow quills in their tail. Porcupines are found country-wide in Namibia except the arid western part of the country. These mostly solitary animals are nocturnal, foraging primarily at night, making them difficult to hunt in a country that prohibits any form of night hunting. Using their powerful digging claws, porcupines can dig for roots, bulbs, and tubers. They also feed on fallen fruit and gnaw on tree bark. With an enlarged appendix containing microorganisms, they can break down undigested plant fibres. They often visit baiting sites for bushpigs, leopards, and lions, and will eat carrion or gnaw on bones, a practice known as osteophagia. Porcupines are considered a species of least concern by the IUCN. However, if trophies are imported to the United States, the US Department of Agriculture (USDA) has special rodent import regulations that must be followed.