Not sure what to think about this. At one of my visits to the polar bear exhibit this day, the female was standing at the bottom of the pit, jumping rather frantically up and down at the visitors looking down on her. The visitors were excited, laughed out loud and almost queued up to take their turns at capturing it with their cell phone cameras safely and perfectly vertically positioned about two meters higher than she could reach with her head and paws. The behaviour went on for at least 10 minutes.
My two pictures here does not document it very well.