how do dolphins sleep?
358470
Dolphin's don't 'sleep' in the sense that we do. They do however have conscious control over their breathing like we do, in which case loosing consciousness in the ocean could be quite deadly. Research into this area suggests dolphins 'sleep' one cerebral hemisphere at a time, meaning they close down one half of their brain for a little while, letting the other half take care of the necessary functions such as breathing.
412064
River dolphins, apparently.
1183018
yes, they "kind of" sleep at nights by not photosynthesing. and yes fish can "kind of" drown by the lack of oxygen..
528053
A dolphin has a three chambered stomach, similar to an ungulate (cow or deer), pointing further to its evolution from a terrestrial ancestor. Since dolphins do not chew their food, the mastication of their meal is taken care of in their first or fore stomach. The majority of digestion is processed in the main stomach or second chamber. The last section of their stomach, the pyloric stomach, takes care of the remainder of their digestion prior to the contents emptying into the intestinal region.
214546
Dolphins have sex for pleasure but all other animals do it for reproduction only
739153
Especially for you is a background and proven history of bottlenose dolphins:\n\nBottlenose dolphins feed mainly on Eskimos and bearded Eskimos. Depending upon their location, they also eat juvenile Eskimos and hooded Eskimos and scavenge on carcasses of Eskimos. Might I also point out that it is a little known fact that dolphins can walk and breathe on land. When Eskimos are unavailable, bottlenose dolphins eat Eskimo berries, and Eskimo garbage. A bottlenose dolphin's stomach can hold an estimated 15% to 20% of its body weight meaning it can eat an entire Eskimo. It can assimilate 84% of the protein and 97% of the fat it eats. Bottlenose dolphins need an average of 4.4 lb. of fat per day to survive, so your average obese Eskimo will suffice. An Eskimo weighing 121 lb. could provide up to eight days of energy for a bottlenose dolphin. \n\nHunting Methods \n\nStill Hunting:\n\nThe bottlenose dolphin remains motionless beside a front entrance to an igloo waiting for an Eskimo to exit. When an Eskimo exits, the bottlenose dolphin bites onto the head or upper body, then flips the entire Eskimo onto the ice. \n\nStalking on Land:\n\nOnce spotted, the bottlenose dolphin slowly and steadily stalks the Eskimo. At 15 to 30 m away, the bottlenose dolphin suddenly charges the Eskimo, with its teeth; the bottlenose dolphin grabs the Eskimo before the Eskimo can enter his igloo. \n\nAquatic stalk:\n\nThe aquatic stalk is a method also used in summer when Eskimos sunbathe on sea ice. The bottlenose dolphin swims toward a hauled-out Eskimo. Once the bottlenose dolphin reaches the ice edge, the bottlenose dolphin quickly emerges from the water and grabs the Eskimo with its teeth.\n\nStalking birth lairs: \n\nStalking Eskimos at their birth lairs is a hunting method bottlenose dolphins use in spring, when Eskimos give birth to their young. Eskimo birth lairs are caves built under snowdrifts next to a hole in the ice. The snowdrifts are on stable sea ice attached to land. Once a bottlenose dolphin identifies a birth lair, it slowly and quietly positions itself next to the lair. If a bottlenose dolphin smells or hears an Eskimo in the lair, it slowly rises up on its hind flippers and crashes down with its flippers to break through the lair roof. To break the roof's hard surface, several tries are sometimes needed, which may allow the Eskimo to escape to its sled. This method is most commonly used by bottlenose dolphin females with pups under one year old.\nMother Eskimos and their young have the high fat content needed for hungry bottlenose dolphin mothers and their growing pups. Male bottlenose dolphins that may attack young bottlenose dolphin pups don't normally hunt Eskimos in birth lairs. Birth lairs are usually on sea ice attached to land, allowing young Eskimos (who have little protective blubber) to avoid crossing water.\n\nInteresting Bottlenose Dolphin Facts\n\n1. Bottlenose dolphins are very sarcastic. \n2. In 1931 Hollywood was scandalized by Fatty Arbuckle's affair with Fru Fru, a (married) bottlenose dolphin. Neither Arbuckle nor FruFru's career (she was an ice-dancer) survived the media backlash.\n3. Many people assume that bottlenose dolphins are mammals. They are in fact a form of fruit resembling a banana.\n4. Just as Jews are often blamed for catastrophic events in the global community, so bottlenose dolphins are often blamed for disaster in the arctic community. Because of this, many bottlenose dolphins refer to themselves as jewdolphins.\n5. Famous musical bottlenose dolphins include Jimi Hendrix, Larry Adler, Cyndi Lauper, Jeff Beck, and of course Bottlenose dolphin.\n6. In 1914 the bottlenose dolphin population of London was 12. It is now 15.\n7. Bottlenose dolphins have the most natural rhythm of all the arctic animals. During spring and summer, bottlenose dolphins often give synchronized swimming classes to students in Brazil. \n8. If you are very sad and very lonely, and you think hard enough about a
31709
I am unsure if it sleeps.\nHowever, its lifespan is not long so it probably does not need sleep and yawn.
447895
No; but they are pretty smart. They're able to grasp some abstract mathematical concepts like addition and subtraction, and even occasionally multiplication - things that our own civilization didn't grasp for quite a while. They can respond quite effectively to stimuli. (Dolphins are also extremely smart.) Of course, they have animal mentalities, and the fact that we are able to categorize and think about them, while they are not able to do the same of us, puts us in a higher school of thought.
273803
they tell to sleep without doing anything
247103
Dolphins are mammals just like us, and so like us they also sexually reproduce.  The male dolphin inserts his penis into the female dolphins vagina where he releases his sperm and so fertilizes the egg.  They kind of float/swim belly to belly.  Their genitals are located on the underside somewhere near the tail.
239796
An animal that is laying down that is not sleeping.
164877
they are mammals so they breathe air
571640
Both dolphins and porpoises are mammals. Even though they both live in the ocean, they are not fish. They do not have breathing gills. They have lungs and breathe air. Both also give birth to live young and nurse those young. A mammal is also characterized by having the presence of hair: when dolphins and porpoises are small, there are small hair follicles. \n\nDolphins and porpoises belong to the same scientific order, Cetacea. This order includes all whales, even the great whales, to which both dolphins and porpoises are related. All cetaceans are completely aquatic mammals, have a streamlined body, a tail fluke, and a blowhole (which is what these air-breathing animals use to breathe). The dolphins and porpoises are also classified in the scientific suborder, Odontoceti, which are the toothed whales. All odontocetes also have the ability to echolocate, the ability to detect objects in their underwater environment using the echoes of a sound, much like sonar. \n\nPorpoises and dolphins are classified into two different families. The porpoises are in the family Phocoenidae and the dolphins are in the family Delphinidae. When separated at the family level, dolphins and porpoises are as physically different as cats and dogs.
287113
I don't know, but why not? They dream. Dogs twich when they dream about chasing something, they also run in their sleep, and growl.
83895
No,dolphins are not nocturnal.
311429
Sleep is one of the last bastions of mystery that Science has yet to conquer. Despite several centuries of study, speculation, and debate, we still really don't know what sleep is or why we need to 'shut down' periodically. We know that all sorts of vertebrate animals – mammals, birds, reptiles, and at least some fishes – periodically enter a period of torpor characterized by a profound change in brain waves.\n\nBut when it comes to whether or not sharks sleep, we just don't know. There have been reports from all over the globe, including Mexico, Japan, and Australia, of sharks resting motionless in caves. These have been called "sleeping sharks", but I can attest that the eyes of these quiescent sharks do follow divers moving about in the caves with them, so they're definitely not asleep.\n\nIn his sweeping epic Paradise Lost, 17th Century English poet, John Milton, asked, "What hath night to do with sleep?" We know from sonic telemetry studies (the underwater equivalent of radio tracking) that at least some shark species -- such as the Reef Whitetip (Triaenodon obesus) and the Tiger Shark (Galeocerdo cuvier) -- are actually more active at night than during the day. Since schooling behavior is partially coordinated by vision, many other sharks are most active at dawn and dusk, when such prey is at a disadvantage. Studies such as these suggest that at least some sharks do not sleep at night.\n\nWe used to think that the Great White Shark (Carcharodon carcharias) was primarily active during the day. But it turns out that this is largely due to observer bias: humans tend to be diurnal rather than nocturnal, and it's very difficult to watch an underwater creature at night. Recent experiments by Peter Klimley using stationary telemetry pods placed along the bottom at the Farallon Islands, we have learned that White Sharks are quite active at night, when they probably feed primarily on bottom fishes. If these bottom fishes are sleeping when attacked, they're certainly in for a 'rude awakening'!\n\nBecause sharks rely on ram-ventilation -- that is, their forward swimming to push oxygen-bearing water through their mouths and over their gills -- this fact begs the question: do sharks sleep at all? Dolphins are conscious breathers, actually having to think about rising to the surface, opening their blowholes, and breathing. From Russian studies carried out in the early 1970's, we know that dolphins catnap in 2 to 3-minute stretches, actually shutting down one hemisphere of their brain at a time. From experiments carried out on a small shark called the Spiny Dogfish (Squalus acanthias), we know that the 'Central Pattern Generator' that co-ordinates swimming movements in sharks is not located in the brain, but in the spinal chord. Thus, it is possible for an unconscious shark to swim.\n\nThere is even a possibility that the sharks' fore, mid-, and hind- brain shut down in sequence, resulting in the shark equivalent of sleep-walking.\n\nI hope this answers your question.
7374
I'm pretty sure that they do. However, if memory serves correctly, dolphins are the only animals that have sex for pleasure(other than humans).