Do fish, sharks and whales sleep? read on in details please...?

Question

more than just a yes... please. Fish don't have eyelids, sharks need to continually move to put water through their gills, whales need to come up for air... how could they possibly sleep?

Answer 1

For whales:
"On land, human beings and other mammals breathe involuntarily: If we don't make a decision to breathe or not to breathe, our body will take in air automatically. Because of their undersea environment, whales and dolphins must be conscious breathers: They have to actively decide when to breathe. Consequently, in order to breathe, they have to be conscious. 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.
Scientists have studied this phenomenon in dolphins, using electroencephalography. In this process, electrodes hooked up to the head measure electricity levels in the brain. The resulting electroencephalograms (EEGs) of dolphin brains demonstrate that in the sleep cycle, half of the dolphin's brain does indeed "shut down" while the other half is still active. Researchers have observed that dolphins are in this state for approximately eight hours a day."

For fish:
"Most all fish spend time in an energy-saving state that can be called "rest", and we might even call their behavior "sleep", though it is probably different than "sleep" in most land animals. Many fish, like Bass and perch, rest on or under logs at night. Coral reef fish active in the day, hide and rest in crevices and cracks in the reef to avoid being eaten at night.
The resting behavior of fish is very different from their behavior the rest of the day. Many minnows, for example, which are very active in schools during the day, scatter and remain motionless in shallow water at night. Many fish "rest" or "sleep" during the day and are active at night instead, but almost all fish sleep."

Sharks, on the other hand, indeed never sleep.

Answer 2

well fish just sleep, they don't need to close their eyes. sharks and whales have half their brain awake so they can come up for air and keep moving

Answer 3

yes, who says you need eyelids to sleep? and also who says things cant move while they sleep, sleep is a brain state not a set of physical conditions. How come bats can sleep, they dont wear pajamas?

Answer 4

i know sharks sleep. Divers have found an underground cave that had a bunch of sharks sleeping in it!!!

Answer 5

you are going to be able to desire to be certain the goldfish isn't in tropical temps with the different tropical fish you have. The tropical fish are advantageous with warmer temps, in spite of the shown fact that it would desire to reason the goldfish stress and various different issues if the temp is basically too extreme for him.

Answer 6

They can shut down a part of their brain until they have rested long enough.

Answer 7

Semi sleeping, maybe.

Answer 8

yes these are slip.

Answer 9

they're half-asleep.