According to the MSPCA, certain kinds of rats burrow underground. In residential areas, the most common of these is the Norway rat. Their burrows are found next to buildings, fences, sidewalks, patios, sheds and decks.
A typical burrow for a Norway rat is 12 to 18 inches underground and runs for about 1 yard. The access hole is anywhere from 3 to 10 inches wide and is usually dug at an angle. Norway rats are brown or reddish gray with gray-white underbellies. Their total length is 12 to 18 inches. Their tails, which have little hair, are 5 to 8 inches long. Norway rats become problematic for humans when they move indoors, depositing urine and feces. Sometimes these animals chew and destroy electrical wiring.