Specimen Storage: Housing Our Mammal Library The Field Museum’s mammal collection is just like a big library. Instead of books, however, we store pickled specimens, skeletons, skins, and frozen tissue; each different preparation is valuable for a particular reason. Like any library, we use a special system of organization so that we know where to find things. Our “dewey decimal system” is relationships: subspecies of rats are kept in the same drawer, rat species are stored in the same case, rodents are located on the same floor. Any scientist accessing our collections can easily find ground hogs without even asking . . . they are located with all other types of ground squirrels. Because the Museum’s collections are so vast and, by necessity, ever increasing, we recently began building a huge new facility to increase on-site storage space. The Collections Resource Center (CRC) will provide 170,000 square feet of climate-controlled housing for our irreplaceable collections. The CRC will help ensure that scientists 1000 years from now can study the specimens we collect today. It will also help combat some of our biggest enemies in this goal: light (that could change the color of the skin); humidity and temperature fluctuations (that could cause cracks in skin and teeth), and insect pests (that could eat the skin).