"Polar Frontier" at the Columbus Zoo is delayed for another month, but interestingly enough the 2 polar bears and 2 grizzly bears will occasionally rotate yards with each other: (The Brookfield Zoo is employing the same tactic in their brand new "Great Bear Wilderness")
Polar bears chill offstage as zoo exhibit awaits completion | The Columbus Dispatch
Did they ever end up having the different bear species rotate yards?