Indiana's river otters had nearly vanished; starting in 1995, wildlife officials released 303 into rivers, and decades later, the species was reported across the state

In early 2026, an area of the White River in Indianapolis had its first signs of a return of the elusive river otter after a tracker found the paw prints and latrine debris left behind by the animal near Eagle Creek Park. This was notable because the species had been absent from much of the state for over 50 years. According to a 2022 book chapter, “Conservation Status of the North American River Otter in the United States and Canada: Assessing Management Practices and Public Perceptions of the Species,” published in the edited volume Small Carnivores: Evolution, Ecology, Behaviour and Conservation (Wiley), sightings like these have been reported in parts of the country and are often cited as a conservation success. Despite having little media attention, the species has made a swift recovery. It is a surprising twist for millennials who grew up with nature documentaries talking about the extinction of species.

River otters used to be abundant in Indiana. However, uncontrolled trapping for their fur, alongside massive habitat destruction, led to the species becoming locally extinct by the mid-1900s (commonly dated to 1942), as per the Indiana Department of Natural Resources. For more than 50 years afterward, river otters remained absent from Indiana's waterways. This was just one of many species that suffered during the 19th and early 20th centuries.

The 303 otters that rewrote the map


In 1995, Indiana wildlife officials started efforts to try to bring the otter back. Between 1995 and 1999, they released 303 river otters caught from healthy wild populations in Louisiana into 12 different areas in the river systems across the state, per the Department of Natural Resources article. They recovered, and by 2005 they were no longer endangered in Indiana. The population continued to increase and now can be found in all counties across the state.

This happened all across the country. The otter has now been reintroduced to 22 states in the USA. Over 4,000 otters have been relocated since the first project in Colorado in 1976, according to the 2022 book chapter. Clean waterways due to the Clean Water Act and natural expansions have made this one of the most successful examples of wildlife conservation in America.

The otter as a watershed’s lie detector

Scientists are increasingly using otters to monitor the health of a river. As they are at the top of the food chain, they eat a lot and therefore will have the highest concentrations of contamination in their bodies. A separate 2022 study titled “Highly contaminated river otters (Lontra canadensis) are effective biomonitors of environmental pollutant exposure,” published in the journal Environmental Monitoring and Assessment, found that river otters are a good biomonitor because researchers can track contaminant levels in the environment by analyzing the chemicals present in otter scat.

This was done by studying otter scat in a river within Washington State that ran through very urban areas. The presence and health of an otter population is itself informative: because otters sit at the top of the aquatic food chain and accumulate pollutants in their tissue, their return to a waterway signals that the ecosystem can now support that food chain again, even though, as the Washington State study found, the otters themselves may still be carrying significant contaminant loads picked up from urban runoff.

A success story with a catch

However, the otter population in Indiana grew so quickly that it was allowed to be trapped in some areas of the state, starting with a limited season in 2015. The species that was listed as state-endangered two decades ago (it was delisted in 2005) is now legally trapped in parts of the state. This isn't unusual within wildlife management in the USA. Success is often measured by how quickly a protected species can become a resource. Whether this is a logical step towards good population management or an ironic twist depends on whom you ask. Indiana's otters remain one of the country's most under-reported wildlife conservation success stories.