The Academy's mammalogy collection is one of the oldest collections in the New World. During the 19th Century the collection grew with donations and purchases from a network of prominent natural historians. Charles Lucien Bonaparte, Samuel George Morton, A.L. Heerman, Wm. McClure, T.B. Wilson, Joseph Leidy, E.D. Cope, Admiral R.E. Peary, George Harrison, Samuel N. Rhoads, and John K. Townsend were among the early collectors and patrons of the collection. The Harrison, Hiller and Furness expeditions to Borneo and Sumatra in 1896-1901 collected a large number of rare specimens now housed at the Academy.

In the first half of the 20th Century, mammalogy at the Academy reached worldwide with collecting expeditions. Among the major expeditions were Brooke Dolan's to Tibet and Western China in 1931-32 and 1933-34, George Vanderbilt's expeditions to Africa in 1934 and Sumatra in 1939, M.A. Carriker Jr.'s expeditions to Peru and Bolivia in 1929-30, 1935 and 1938, Robert K. Enders' to Panama in 1935, 1937 and 1941, Wharton Huber's to the southwest U.S. and Mexico in 1927, 1929, 1931, 1932, 1933, Nicaragua in 1922, and Louisiana in 1934, and O.P. Pearson's to Panama in 1938.

Since 1943, in-house mammal research has been virtually absent from the Academy. Occasional curatorial work and research by Karl Koopman, Richard Estes, Charles Smart, and Frederick A. Ulmer, Jr. are the exceptions. During this time outside, however, researchers have continued to use the collection. Current work is aimed at keeping the collection accessible for research and improving curation and storage conditions so that data is updated, clarified and preserved, and so that the specimens do not degrade in quality.