can dolphins swim when they are sleeping?

Answer 1

Dolphins do sleep, but not quite in the same way that people do. They sleep with one half of the brain at a time and with one eye closed. Dolphins rest this way on and off throughout the day, switching which side of the brain they shut down. During these periods, everything inside the dolphin slows down, and the mammal moves very little.

Dolphins have to be conscious to breath (Williams et al, 1990). This means that they cannot go into a full deep sleep, because then they would suffocate. Dolphins have "solved" that by letting one half of their brain sleep at a time. This has been determined by doing EEG studies on dolphins. Dolphins sleep about 8 hours a day in this fashion. Recent research confirmed that dolphins have only one eye closed when sleeping. The state (open or closed) of one eye remains constant for on average an hour, after which it switches state (Goley, 1999). REM (Rapid Eye Movement) sleep, usually associated with dreaming has been recorded only very rarely. Some scientists claim dolphins do not have REM sleep at all.

A dolphin's behavior when sleeping/resting depends on the circumstances and possibly on individual preferences. They can either:

- swim slowly and surface every now and then for a breath

- rest at the surface with their blowhole exposed

- rest on the bottom (in shallow water) and rise to the surface every now and then to breath.

Whales and dolphins are mammals, so in a lot of ways, they are just like human beings. Among other things, they have similar bone structure, are warm-blooded and give birth to live young. The biggest difference between these animals and human beings are related to our respective environments. Whales and dolphins have a unique respiratory system that lets them spend long periods of time underwater, without taking in any oxygen.

Because of their undersea environment, whales and dolphins must be conscious breathers: They have to actively decide when to breathe. This presents a problem, since mammalian brains need to enter an unconscious state from time to time in order to function correctly.

There's plenty of time for a dolphin to catch a catnap between trips to the ocean surface, of course, but this isn't a viable option. When you're a conscious breather, it's just not feasible to be completely unconscious -- what if you don't wake up in time? The solution for whales and dolphins is to let one half of the brain sleep at a time. In this way, the animal is never completely unconscious, but it still gets the rest it needs.

Answer 2

If a dolphin stops swimming it will die. During sleep, one half of the brain stays active while it 'sleeps' - they are still swimming but not as actively. They then switch to the other half of the brain, while the previously working half gets its turn in sleeping.

Answer 3

First of all, I am not a dolphin expert. There.

I do think they CAN swim when just ABOUT asleep, but I think they sleep quietly.

They can also wake up VERY easily and quickly when necessary. Most mammals can when danger threatens or dinner is ready.

The only ocean creature I know of that moves constantly is the shark, but you may know that too!

(PS. Sorry about all the capital letters...I get frustrated when I can't use italics. I don't mean to shout.) :)

Answer 4

Yup with one eye open, to watch out for dangers