The otters at Japan's Keikyu Aburatsubo Marine Park live in a truly amazing habitat that shows off the animals' carefree demeanor. Clear tubes – some straight and some circular – act as waterways that allow the otters to swim lightheartedly in fun patterns. The circular tubes function much like roundabouts on city streets, enabling “traffic flow” to change directions on a dime.
When the otters aren't swimming, they have plenty of other activities available. The clear tubes are only part of the zoo's innovative exhibit that includes spacious, glass-encased tanks, ladders and toys on dry land. Because they're kept so happy in a stimulating environment, the otters even seem pleased to interact with guests through the glass.
Keikyu Aburatsubo Marine Park website
via [Neatorama, Notcot]