関連ワード:  why do dolphins float upside down    why do dolphins swim upside down    why do dolphins swim upside down in captivity    why do dolphins swim upside down and chomp    why do dolphins swim upside down in the ocean    why do dolphins swim up and down    why do commerson's dolphins swim upside down    why do bottlenose dolphins swim upside down    why do pacific white sided dolphins swim upside down    what does it mean when a fish floats upside down