Simplify the following text for a Grade 7 native English-speaking person.
Original: Knut ( 5 December 2006 â `` 19 March 2011 ) was a polar bear who was born in captivity at the Berlin Zoological Garden .
Simplified: Knut ( 5 December 2006 - 19 March 2011 ) was a polar bear who was born in captivity at the Berlin Zoo .