http://www.youtube.com/watch?v=aWrdpURgVgM That bear and her cub seem to understand gravity, center of gravity, balance. I wonder what else they can comprehend. My shih Tzu knows not to jump off a high table. He seems scared. How does he even know this, and not recognize himself in the mirror though? He also knows to not run full speed into a wall. I know they are completely different levels of intelligence, but I would say understand gravity, momentum, and what it can do to your body is a higher level than self recognition, wouldn't you?