How Do Dolphins Sleep?

We all know that dolphins are marine mammals. Since they are mammals, they need to be conscious in order to surface and get air. So, how do they sleep? EEG studies of dolphins show that they sleep one side of their brain at a time with the opposite eye closed. This is their way of getting rest and still making sure that they get air. They either drift near the water’s surface and come up every so often to get air or they rest at the surface with their blowhole exposed. Dolphins usually sleep at night for about 8 hours, but they only sleep for a couple hours at a time. They have very little REM sleep and do not go into deep sleep. Some dolphins can dive up to 900 feet and hold their breath for up to 30 minutes. However, they usually average 8 to 12 breaths a minute while they are active and 3 to 7 breaths a minute while they are resting.