Death of Knut the Polar Bear Is Explained at Last (Published 2015)

Knut in his enclosure at the Berlin Zoo in 2010, a year before he died at age 4.Credit...Barbara Sax/Agence France-Presse — Getty Images HEIDELBERG, Germany — Scientists have solved the zoological mystery of what killed Knut, the Berlin Zoo’s famous polar bear, more than four years after he drowned in his enclosure as horrified visitors watched. The 4-year-old bear had an autoimmune disease that a