Although their tank is quite small the Californian sea otters at the Georgia Aquarium seem to enjoy themselves, and doing exactly what a lot of people think is funny about them, floating on their back while exercising their forefeet as if to break the shell of a clam. The sea otter is one of the few species that use tools during foraging. They can even 'store' a favourite tool such as a rock, under a skinfold near their arm pit, for future use.