While almost universally scorned, rats are incredible collectors of ephemeral items that rarely survive in other collections.  However, far from actively trying to create a historic archive, rats instead select items to build comfortable nests.  The nest building process continues even after the original rat dies as succeeding generations of rats continue to add items to the nest.  Therefore, over the course of hundreds of years, a rat nest can grow to be very large and can contain samples of a house’s decorative finishes that span many generations.  Because of this wealth of historic material, if a nest is carefully inventoried, artifacts can be found that provide architectural historians and curators with an amazing amount of information about the evolution of a house’s interior design.  However, because each new generation of rat churns and mixes the contents of the nests, it is normally impossible to date items in the nest using stratigraphy and so material analysis is required to determine the age of the artifacts recovered.