Once heavily hunted by fur trappers, river otters in Illinois gained state protection the 1920s, and their population numbered fewer than 100 by the 1970s.
The Illinois Department of Natural Resources began to reintroduce river otters to the state in 1994, trading 75 wild turkeys to Kentucky for 50 wild river otters from Louisiana. More and more otters were acquired, and by 1987, the downstate population has been reestablished.
The Daily Southtown said by the 2010s, river otters had started showing up in Cook County forest preserves, and now the IDNR has established the urban otter research project to learn more about their adaptation to an urbanized location.