how come no matter how fast fish swim they never sweat?
108061
Because fishes are cold blooded animals....sweating is a way for regulating temperature that is often employed by mammals.
391527
They could. There were fish that evolved from swimming to walking. There is a fish called the flying fish that can jumpfrom the water and glide through the air for a ways to escape predators. Follow the link to see a picture, its fins look very similar to wings.\n\n\nhttp://oceanlink.island.net/oinfo/biodiversity/flyingfish/flyingfish.html
166054
There’s a fairly complicated evolutionary history to this trait. Trout started out initially as freshwater fish. As time went by their ancestors moved initially into brackish rivers, then into estuaries and finally into the oceans. But because they evolved in freshwater their eggs could still only survive in freshwater. So every year the trout ancestors had to move from the ocean back into the freshwater.\n\nBut as trout moved through the oceans they gradually discovered new rivers and streams in new countries, or streams that had just recently formed. Trout bred in those new streams, and some of them never moved back to the oceans. As a result today  there are lots of different types of trout. While most move back to the oceans after they hatch some live out their entire lives in freshwater. Others, like the steelhead, can do either, with some individuals returning to the oceans and some staying in the freshwater where they were born.\n\nBut because all trout ancestors evolved to swim from the ocean back up the freshwater streams most trout do the same today. Even those trout that never leave the freshwater feel that same urge to move higher upstream. But it should be noted that some trout species don’t swim upstream. Instead they swim towards clean water, which in many places can be downstream. But they still retain that same ancestral urge to migrate when it comes time to spawn.\n\nOddly enough many species of fish do exactly the opposite. These fish evolved in saltwater and although they spend most of  their lives in freshwater rivers and lakes they return to the ocean to spawn. The best known examples are the eels. The world contains lots of eels species that live in freshwater, but all return to the deep ocean where they first evolved in order to mate and lay eggs. Then the babies swim thousands of miles up out of the abyss and back up the same rivers their parents left.\n\nBiologically speaking trout swim upstream in repsonse to sex hormones that cause them to first seek highly oxygenated water and then to fight the current.\n____________________________________\n\nAddenda\n\nDogsmyjob said "Trout are fresh water fish only."\n\nI have no idea where you get yuour information, but you are completely and utterly incorrect. Most trout species remain anadromous, ie they return to the sea as adults. Why do you think there are  several species called sea trout?\nDon't believe me? Folow the links below.\n\nBut hey, at least you learned something today. \n\n"Anadromous bull trout rear in natal streams and migrate to marine environments to mature."\n\n"Rainbow trout are primarily a freshwater fish, although sea-run populations, often known as steelhead, exist in some areas. It is unclear whether this migration to sea water is genetic or simply opportunistic, but it appears that any population of rainbow trout is capable of migrating to or surviving in the sea if the need arises "\n\n"The shoals drop downstream during the night. A 'spate' will mitigate the change from fresh to salt water and particularly at these times the fish migrate to sea. Those fish not migrating return upstream for one more summer's growth."
644477
You CAN sweat while swimming.  It depends how much you exert yourself, how warm the water is, and how prone ou are to sweating.
194730
I think it has something to do with the fact that the fish are not grounded to the earth so the current just travels around them not through them.
448554
they use gills. the gills are filled with lots of blood vessels.  the fish draws in water from the mouth, which passes by and out the gills. as the water moves by, the blood cells take in oxygen and the waste gases are released.
519851
Fluids are not compressible and since most sea creatures cells/bodies are fluid, they are not affected by the pressure.  Air however is compressible so if the had lungs filled with air, they would have increase the amount of air in the lungs as they dove or get crushed.  Fish with swim bladders have to gradually increase the air in these bladders, if you catch one and reel him up from let's say 200', he is very dead by the time he makes it to the surface as the bladder ruptures as the air expands.
494603
Pigs don't sweat. Well they do, but only form their noses, and only a tiny amount.\n\nThe tiny amount of sweat that they do produce is either clear or a pale milky colour.
753941
They are mammals, so they have lungs and can not absorb enough oxygen to survive.  Dolphins evolve from a land animal that return to the sea.  There is a belief that dolphins can absorb oxygen from the sea, but because they are warm blooded, they require large amount of oxygen, which sea water can't provide. Many warm blooded animals evolve to become sea creature, because of the abundents of food.  Warm blooded animals are smarter and in some ways faster than cold water animals, gave an incentive for some species to become sea creatures.  Warm blooded animals though require large quantity of oxygen to run its supercharged matabolism, which why fish never evolve into being warm blooded.
1021680
Depends on the kind of fish!\n\nTrouts need an extreme amount of oxygen, while some other fish could do with 10% of the amount...
1183018
yes, they "kind of" sleep at nights by not photosynthesing. and yes fish can "kind of" drown by the lack of oxygen..
1144156
My friends and I have the same debate, and we call it the "Blubber Theory".  It is not scientific, but assume that since the body lose heat from being in the water for so long, it start to adapt to its environment by creating "blubber" to prevent excessive heat loss.  N.B. This is not scientific, but the blubber is higher in swimmers who spend more time in the water and who dont alternate with another sport/activity.
336386
I'm sorry, I can't find a centralized web site.  I found that gorillas and orangutans can't swim because of their low center of gravity.  I guess armidillos swim by inflating their stomachs with air.  \n\nHowever, future research on ask.com says all mammals can swim. So, I really don't know.  You have to figure anybody can post something on the internet whether it's true or not.
438215
Most mammals are able to swim if they absolutely have to.  It's true that some might drown while attempting to, but that doesn't mean that the species itself can't swim.  Dolphins and seals sometimes drown too, but no one would say they can't swim.\n\nHow well a particular species of mammal can swim depends a lot on their physiology.\n\nAnimals with higher density of muscle than fat tend to sink instead of swimming.  Even if they have the limb mobility and strength that should be allow swimming, they have tremendous difficulty keeping above water.  Most primates actually fit into this category.  Chimpanzees in particular tend to sink like a stone in water, and avoid swimming at all costs.  Humans are very unusual in their ability to swim, and affinity for water (which raises a whole other set of questions, but that's another topic).\n\nIf they don't have much fat, thick fur can also help keep a mammal afloat.  Dense underfur traps air and can act like a flotation device.  Baby sea otters actually have difficulty diving because their fur traps so much air that they can't swim hard enough to reach the bottom.  Once again primates, with their thin, sparse coating of hair lose out on the flotation front.\n\nAnother factor is limb mobility.  Critters that can't move their arms and legs as swiftly or don't have enough surface area to push water aside tend to be crappy swimmers.  Anteaters tend not to be great swimmers, and camels aren't likely to win any swim meets either.\n\nIn general, mammals are pretty good swimmers.  Most mammals have some fat, most of them have hair or fur to trap air, and they have the limb mobility to move around.  Mammals can also close their mouths or noses and block their breathing passages so they don't take water in.  Critters like insects and spiders don't have that option, and unless they have other adaptations they tend to drown fairly easily.
351401
Well-trained athletes CAN pump more blood from their hearts at maximal exercise, but the main reason they tend to have slower heart rates is because their muscles are much more efficient when it comes to extracting oxygen from their blood.  Therefore, for the same amount of work that their muscles are doing, not as much blood flow is needed to supply the necessary amount of oxygen.  Therefore, their hearts don't need to pump as fast or as hard to keep the muscles well-supplied with oxygen.\n\nThink of it as two people standing on a riverbank.  One guy (the non-athletic heart) is using a crappy fishnet and can only catch 10% of the fish that swim by.  If he needs 10 fish an hour to survive, he needs to have 100 fish swim by to in an hour.  If the guy next to him (the athletic heart) has a brand new fishnet that can catch 50% of the fish that swim by and HE needs 10 fish an hour to survive as well, he can do just fine with only 20 fish swimming by every hour.  Does that make sense?
1184568
With the exception of lungfish, most fish don't last long out of water because they can't breathe.  They die within minutes As well, they can't move at all so they are sitting prey for predators. In hot weather, they also dry out quickly.
891823
It was once believed that all sharks had to swim constantly in order to breathe and could not sleep for more than a few minutes at a time. Oxygen-rich water flows through the gills during movement allowing the shark to breathe. While some species of sharks do need to swim constantly, this is not true for all sharks. Some sharks such as the nurse shark have spiracles that force water across their gills allowing for stationary rest. Sharks do not sleep like humans do, but instead have active and restful periods.\nhttp://www.flmnh.ufl.edu/fish/sharks/nsrc/Basics.htm#sleep\n\nIt is unclear how sharks sleep. Some sharks can lie on the bottom while actively pumping water over their gills, but their eyes remain open and actively follow divers. The spiny dogfish's spinal cord, rather than its brain, coordinates swimming, so it is possible for a spiny dogfish to continue to swim while sleeping. It is also possible that a shark can sleep with only parts of its brain in a manner similar to dolphins.\nhttp://en.wikipedia.org/wiki/Sharks#Shark_sleep\n\nIt depends what you mean by sleep. When humans sleep we are not conscious of what is going on around us, we kind of shut-down for a while and are not able to walk around unless we happen to be sleep-walking. Sharks rest in a different way. They can rest part of their brain while still swimming along, semi-aware of what's around them. Sharks that are able to stop swimming will settle on the seabed, and species like the British Bullhuss shark actually close their eyes - so they appear to sleep like we do. In our aquarium I have seen two Sandtiger sharks bump into each other nose-to-nose. They were so startled, they both took off at great speed in opposite directions. This suggested to me that they were dozing on the move and not paying full attention to where they were going, but I have never seen them bump into the sides of the tank when snoozing, so they normally seem to have an idea of where they are. A lot of research has been done on sleep in humans, and many mysteries still surround sleep and its importance to healthy living, but conducting similar research on sharks is almost impossible for practical reasons, we have a lot to learn about sleep and its purpose in fish and other animals.\nhttp://www.national-aquarium.co.uk/databases/FAQsLibrary/index.asp?FAQCategoryID=&FAQID=767&Sear