Observations of bottlenose dolphins in aquariums and zoos,and of whales and dolphins in the wild,show two basic methods of sleeping: they either rest quietly in the water,vertically or horizon- tally,or sleep while swimming slowly next to another animal.

• 对水族馆和动物园的宽吻海豚以及野生鲸鱼和海豚的观察表明，它们有两种基本睡眠方式：要么在水中垂直或水平地静养，要么在挨着另一个动物慢慢游动时睡觉。