The first concerted effort to collect mammal specimens for research purposes was instigated by Myron Swenk at the early part of the 20th century. Terry A. Vaughan was a student and contributed collections in the late 1950s. Vaughan’s textbook "Mammalogy" was first printed in 1972 and is in its 6th edition. J. Knox Jones, Jr. contributed specimens in the 1940s and 1950s culminating in his "Distribution and taxonomy of mammals of Nebraska" (1964). Dr. Harvey Gunderson was assistant director of the museum, professor in Zoology, and curator of Zoology from 1964-1977 during which he also produced a textbook for mammalogy in 1976. In 1997 the Chadron State College (Nebraska) and in 1999 the University of South Dakota mammal collections were transferred to UNSM and incorporated in the collections. Hugh H. Genoways, a mammologist and museum director (1986-1994) added to the collections (primarily Antillean bats), including describing two new subspecies of bats from Grenada and Montserrat in 1998. Genoways and colleagues also produced "Mammals of Nebraska--Checklist, Key, and Bibliography" (2008). A newly discovered species of Panamanian bat (Cynomops freemani) was named in 2018 for Zoology’s recently retired curator, Patricia W. Freeman. In 2019 the University of Nebraska – Kearney (formerly Kearney State College) collections were transferred to UNSM (not yet in this dataset). The collection now has over 21,400 specimens primarily from Nebraska and the northern Great Plains and includes nearly 1,000 collected prior to 1925. Like most state collections, the UNSM mammal collection contains many large series of single species useful for population studies, but now there are substantial holdings of whole skeletons (6,300). An excellent collection of big game trophy heads collected by Mr. Elgin Gates in the mid-20th century are displayed in the halls; these have data and represent several endangered and threatened species.