Lynn Rogers, Ph.D., has been studying black bears for nearly half a century.

Since Rogers began placing webcams in bear dens three years ago, "Lily" at the North American Bear Center in Ely has become an internet sensation.

Each year, the website attracts more than 6 million visitors that follow Lily and her cubs. The mother bear recently gave birth to twin cubs Saturday with thousands watching online.

Over the years, the nationally-acclaimed researcher has butted heads with the Minnesota Department of Natural Resources over his research and education practices, the Duluth News Tribune reports.

In late December, the DNR restricted Rogers' research permit by cutting back the number of bears he's allowed to radio-collar from 15 to 12.

The letter from DNR Commissioner Tom Landwehr cites lack of published scientific research by Rogers over the last 10 years and claims bears have created a nuisance for people who own homes and cabins near the center.

Rogers tells the newspaper that he's published four papers, three of them peer-reviewed, since 2007. A fourth peer-reviewed paper should be published soon, Rogers says, and his book will be released this spring.

Rogers is preparing a detailed response to the DNR's letter.