The pack rat, also known as the wood rat or trade rat, is a rodent of one of several species in the genus Neotoma. Very often, people mean the bushy-tailed woodrat ("Neotoma cinerea"). Packrats are common in the deserts and highlands of the western United States and northern Mexico. They are smaller than a usual (Old World) rat, and usually have long, sometimes bushy tails. They are also not related to the rat, other than also being a rodent. 