The return of the predators

As cougars return to their historic range, it will be humans who must adapt

American mountain lions, or cougars, are re-emerging in areas of the United States, reversing 100 years of decline. The evidence of our study, published in the latest edition of "The Journal of Wildlife Management," raises new conservation questions, such as how humans can live alongside the returning predators.

The cougar population declined dramatically from 1900, due to both hunting, and a lack of prey, leaving the remaining population isolated to the American west. Now comes hard evidence that the western population has spread, with cougar populations re-establishing across the Midwest and continuing to move east.

Three main cougar populations exist in the Midwest, centered around The Black Hills in South Dakota, however, cougars are venturing far outside of this range. One male cougar from the Black Hills was found to have traveled 2,900 kilometers through Minnesota, Wisconsin and New York, before ending up in Connecticut.

While the distance the Connecticut cougar traveled was rare, our research determined that many cougars are roaming long distances and are moving back into portions of their historical range across the Midwest. The study confirmed the presence of cougars over a vast area from Texas, Arkansas and Nebraska, to the Canadian provinces of Ontario and Manitoba.

Working alongside scientists from Southern Illinois University Carbondale and The Cougar Network, we analyzed cougar sightings that have been reported since the 1990s to characterize confirmed sightings, assess habitat suitability and confirm where cougar populations are being re-established.

Aside from confirmed sightings, evidence included carcasses, tracks, photos, video, DNA evidence and cases of attacks on livestock across 14 states and provinces of North America. Only sightings that were verified by wildlife professionals were included, while sightings of animals known to be released from captivity were excluded to ensure only natural repopulation was analyzed.

The results reveal 178 cougar confirmations in the Midwest with the number of confirmations steadily increasing between 1990 and 2008. Approximately 62 percent of confirmed sightings took place within 20 kilometers of habitat that would be considered suitable for cougar populations.

When cougar carcasses were recovered, 76 percent were found to be male. As the Connecticut example shows, males are capable of traveling long distances and this finding suggests males are leading a stepping-stone dispersal of the cougar population.

The evidence helps to confirm that cougars are re-colonizing their historical range and reveals that sightings have increased over the past two decades. The question is how the public will respond after living without large carnivores for a century.

Public awareness campaigns and conservation strategies will be required across an increasing number of states.

Michelle LaRue is a research fellow for the Polar Geospatial Center at the University of Minnesota. Clayton K. Nielsen is assistant professor of forest wildlife in the Cooperative Wildlife Research Laboratory, Department of Forestry and Center for Ecology at Southern Illinois University, Carbondale.