Wood rats, also known as packrats, can be found mostly in North America. The western wood rat resides in the western states, as well as areas of Canada and Mexico.
Western wood rats have bushy tails and are usually about 14 inches long. They are grey in color, omnivorous and nocturnal, but are shy and rarely seen by humans. Western wood rats create their dens in caves and sometimes in the walls and attics of homes. However, this is very rare.
Western wood rats build their nests from found materials, and have earned the name “packrat” due to this unique characteristic. Western wood rats use paper, bottle caps, shingles, cactus, feathers and other trash to create dens. Western wood rats also have the unique trait of “trading” objects that they find. They are particularly attracted to shiny things. If they find an object they prefer more than the one they are currently carrying, they will drop the current object, “trading” it for the shinier one.
The nests are also known as middens. Middens are a common name used to describe waste heaps found in archeological sites. These sites were identified as the areas where household waste from ancient humans could be excavated, lending clues to how civilizations lived long ago.
Western wood rat middens are also known for their longevity. Some middens have been found to include objects that were over 40,000 years old. The reason for this preservation lies within the western wood rat's habit of urinating in the nest. This urine crystallizes and cements the nest, preserving it for generations. Western wood rats will live in these nests for a number of decades and abandon them, creating new nests.