Mammals from Wisconsin are strongly represented; other states are broadly represented; significant collections are present from South America, Africa, Europe, Asia, and Australia. Many specimens are from the period of the first state and national biological surveys. These early collections were made by mammalogists H. H. T. Jackson, Joseph Dixon, Ernest P. Walker, William H. Elder, A. Brazier Howell, A. W. Schorger, and W. E. Snyder among others.
Mossman Developmental Collection: The collection includes hundreds of fluid preserved samples of fetal membranes and female reproductive tracts of mammals (majority from Africa and North America); additionally there are over 100,000 mounted tissue slides of reproductive organs from these mammals. Researchers visit from around the world to study these specimens, many of which cannot be found in any other institution.