Ridgway S H, Harrison R J, Joyce P L
Science. 1975 Feb 14;187(4176):553-5. doi: 10.1126/science.163484.
Telemetric studies of electroencephalograms, electrocardiograms, and electroculograms and concurrent observations of behavior revealed that seals can sleep underwater, on the surface, or while hauled out. Rapid eye movement preceded slow wave sleep and was accompanied by increased respiratory rate and rhythmic tachycardia. While slow wave sleep occurred under all sleep conditions, rapid eye movement occurred only when a seal was hanging at the water surface or hauled out, never underwater.
对脑电图、心电图和眼电图的遥测研究以及对行为的同步观察表明，海豹可以在水下、水面或上岸时睡觉。快速眼动先于慢波睡眠出现，并伴有呼吸频率增加和节律性心动过速。虽然慢波睡眠在所有睡眠条件下都会出现，但快速眼动只在海豹悬挂在水面或上岸时出现，从未在水下出现。
