Query: What zoo are the bears of Bern kept?
Context: Since the 16th century, the city has had a bear pit, the Bärengraben, at the far end of the Nydeggbrücke to house its heraldic animals. The currently four bears are now kept in an open-air enclosure nearby, and two other young bears, a present by the Russian president, are kept in Dählhölzli zoo.