Mammals are a well studied group in Iowa. Unfortunately, many of the large, charismatic animals that are a part of this group are gone--extirpated from Iowa.

Bison, elk, black bears, gray wolves, mountain lions, and moose are all effectively extirpated from Iowa, at least in the wild. We do get reports of bobcats, mountain lions, and black bears wondering into Iowa, usually from the wild although sometimes from captivity. Oftentimes someone kills these vagrants out of fear.

I have seen a list of the mammals of Iowa from the Iowa Gap Analysis program. That list included 81 species. The link for that site is: http://www.gis.iastate.edu/gap/

 Due to their large size mammals have generally gotten a fairly good amount of attention towards their conservation needs.