The Illinois State Museum's zoology collections contain over 140,000 specimens representing mammals, birds, reptiles, amphibians, fish, insects, and mollusks. The museum's collections of vertebrate skeletons and fresh water mollusks are among the most extensive of their type in the U.S. They include large series for many Midwestern species and constitute one of the best comparative collections in the country for the identification of animal remains from archaeological, paleontological, and contemporary forensic contexts.