Porcupines live in a variety of habitats across different continents. They occupy tropical and temperate regions in parts of Asia, Southern Europe, Africa, and North and South America. They live in forests, deserts, rocky outcrops, and hillsides. Some species, especially New World porcupines, live in trees, while Old World porcupines prefer rocky environments. They can live at elevations up to about 3,700 meters (12,100 feet) and are generally nocturnal but occasionally active during the day. Specifically, North American porcupines are native to coniferous and mixed-forest habitats of Canada, the northeastern and western United States, and northern Mexico. They also adapt to grasslands, desert shrub communities, and tundra. They make their dens in hollow trees or rocky areas. In the northeastern US, they are mostly found in forested areas and occasionally in rocky caverns or hollow logs used as dens. Porcupines can also be found in open tundra, deciduous forests, and desert chaparral throughout their range.