• dens
  • Because of the energy needed to travel through the snow, Porcupines usually feed just a short distance from their winter dens, more often than not within 200 feet. (wordpress.com)
  • They are used every night when Porcupines leave their dens to feed and again several hours later when they return. (wordpress.com)
  • night
  • The porcupine, wolverine, and the skunk are the only North American mammals that have black and white colors because they are the only mammals that benefit from letting other animals know where and what they are in the dark of the night. (wikipedia.org)