Cougars are re-populating their historical range in areas of the U.S. Midwest, reversing 100 years of decline, researchers say. The evidence of the resurgence of the big American cats raises new conservation questions such as how humans can live alongside the returning predators, they said. \"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,\" Michelle LaRue from the University of Minnesota wrote in The Journal of Wildlife Management. \"Here we present the hard evidence that the western population has spread, with cougar populations re-establishing across the Midwest.\" While the three main cougar populations in the Midwest are centered around The Black Hills in South Dakota, cougars are venturing far outside of this range, researches said, and one male cougar from the Black Hills was found to have traveled 1,800 through Minnesota, Wisconsin and New York before ending up in Connecticut. \"While the distance the Connecticut cougar traveled was rare, we found that cougars are roaming long distances and are moving back into portions of their historical range across the Midwest,\" LaRue said. \"Our study took in over 3,200,000 square kilometers [1.2 millions square miles] of territory, confirming the presence of Cougars from Texas, Arkansas and Nebraska, to the Canadian provinces of Ontario and Manitoba.\" \"The question now is how the public will respond after living without large carnivores for a century,\" she said. \"We believe public awareness campaigns and conservation strategies are required across these states, such as the Mountain Lion response plans already in place in Nebraska and Missouri.\"