Polar Bear Handstand
– "So the dirty water goes away."
– It loves shellfish and is digging for clams, mussels or oysters.
– It noticed the camera, and the observer-expectancy effect kicked in.
– It's preparing to audition for a Coca-Cola commercial.
– Those seagulls dared it to.
– It lost a contact lens.
Granted, some of the hypotheses are more plausible than others. Got a better explanation? Share it in the comments.