TAHOE CITY, Calif. — A mysterious disease has stricken several young black bears captured in the Sierra Nevada, and one telltale sign is their fearlessness at being around humans.
California veterinarians said in the past 12 months, officials have captured four bears with encephalitis, which can be caused by a body's immune system attacking itself. Although bears normally shy away from humans, the sickly bears aren't showing fear.
Scientists have discovered five new viruses in some of the bears with the symptoms, but they have not determined whether the viruses are to blame for the disease.
WATCH ALSO:
