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Education Science

Warm-blooded Fish? 342

Posted by Hemos from the sounds-mighty-fishy-fishy-har-de-har dept.
DIY News writes "Scientists now have direct evidence that the north Pacific salmon shark maintains its red muscle at 68-86 degrees Fahrenheit, much warmer than the 47 F water in which it lives. The elevated muscle temperature presumably helps the salmon shark survive the cold waters of the north Pacific and take advantage of the abundant food supply there. The heat also appears to factor into the fish's impressive swimming ability."
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Warm-blooded Fish? More

Warm-blooded Fish?

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  • I knew it! (Score:4, Funny)

    by Greyfox ( 87712 ) on Monday October 31, 2005 @10:10AM (#13915036) Homepage Journal
    Damn reptiles... always trying to copy us!

    The next round of global warming is going to see warm blooded land-dinosaurs roaming the tropical forests of the North American continent. We'll all be sorry then!

    • Re:I knew it! (Score:5, Insightful)

      by Omega Leader-(P12) ( 240225 ) on Monday October 31, 2005 @10:18AM (#13915098)
      Fish != Reptiles; Fish = Fish
      • Fish != Reptiles; Fish = Fish
        Shouldn't that be Fish == Fish?

        Moreover, from a cladistic [wikipedia.org] point of view, all reptiles are fish (and so are all humans ;-).

      • Fish != fish !? (Score:3, Interesting)

        by Shark ( 78448 )
        This is still a bit of a debate, but:
        Shark != Bony Fish, Sharks = Cartilaginous fish

        The distinction is important, because taxonomy-wise, that makes them as different from 'fish' (bony) as mammals, amphibians, reptiles or avians. It's a split at the class level. A warm blooded shark is not as impressive as a warm blooded bony fish would be.

        Of course, since chondrichythes (cartilaginous fish) and osteichythes (bony fish) still contain the word chythes (fish), sharks are still refered to as 'fish' but biolog

    • Re:I knew it! (Score:4, Informative)

      by caddisfly ( 722422 ) on Monday October 31, 2005 @10:24AM (#13915143)
      "Damn reptiles... always trying to copy us!"

      ...and this is why we need to continue to teach *science* in science class 'cause last time I checked, salmon sharks were not reptiles.

      These findings just confirm the "above ambient temp" findings that have been known for quite a while with bluefin tuna, other big sharks, etc.

      ...the evolutionary implications are that these "heater" systems allowed these predators to extend their hunting range and hunting efficiency by moving into and operating in colder waters and thus increasing the amount of food available to them --- presto, evolutionary success!

      ...that was until the commercial fishing and technology came along to start wiping them out

      • Re:I knew it! (Score:4, Funny)

        by KrancHammer ( 416371 ) <GunseMatt AT hotmail DOT com> on Monday October 31, 2005 @10:41AM (#13915289)
        Along the discovery that salmon shark thermoregulate (duh), a more interesting discovery is the that of the fundamental division of Slashdot posters. No, not liberals and conservatives, not pro-Firefly and anti-Firefly, not religious and non-religious... no, the fundamental division are those with senses of humor and the psychological capability for detecting the same, and those without.
      • ...that was until the commercial fishing and technology came along to start wiping them out You know, its a really really simple thing to solve: Don't eat fish and nobody will catch them.
        I personally hate fish. Problem solved.
      • ...that was until the commercial fishing and technology came along to start wiping them out

        The sharks evolved heaters to move into colder waters for more prey. The humans evolved fishing boats and nets to move into damned near any water for more prey. What the sharks need to do is evolve torpedoes as a defensive mechanism ...

        • The humans evolved fishing boats and nets to move into damned near any water for more prey.

          I was wondering why that boat was growing on my left foot. I guess random genetic mutation caused it to be there.

      • The immediate question I had was how higher temperatures help the shark survive.

        Obviously, plenty of fish in this area are cold blooded and OK with it. Cold water of course can hold higher levels of O2 than warm water, and so you have more animal activity in the cold oceans. However, as I am thinking about it cold blooded animals (reptiles, insects) get sluggish at lower temperatures, so maybe the main advantage here is that the shark can move faster in cold water and thus is a more effective hunter.

      • Re:I knew it! (Score:3, Insightful)

        by sillybilly ( 668960 )
        Warm blood has a huge cost. Snakes can go for weeks or even months to a full year without eating, simply beause they don't need to maintain all that energy wasting hot body temperature. In water, maintaining a body temperature of 37C like mammals, or 42C like birds, might be impossible, because compared to air, the rate of heat loss in water is just so much greater. So all these fish get is something above ambient, and you can bet that they have to hunt and feed and pay very dearly with energy-cash for each
    • It is a cartilagenous fish. Common ancestor somewhere way back, but still different. This is also not localized to this fish. Tuna and other sharks exhibit this. It is called regional endothermy, or also heterothermy. We just learned about it in Vertebrate Zoology. It has been hypothesized it allows them a huge increase in swimming speed for attacking prey.

  • Big Question... (Score:3, Funny)

    by Ritz_Just_Ritz ( 883997 ) on Monday October 31, 2005 @10:14AM (#13915062)
    How to convince my mother-in-law to stop swimming. 8-)

  • "maintains its red muscle"... (Score:5, Funny)

    by PurplePhase ( 240281 ) on Monday October 31, 2005 @10:16AM (#13915083)
    Is that what the kids are calling it these days?

    8-PP

  • Other warm-blooded "cold-blooded" creatures (Score:5, Interesting)

    by G4from128k ( 686170 ) on Monday October 31, 2005 @10:20AM (#13915108)
    Many insects also create intentionally elevated body temperatures (generally through shivering). Moths, bees, dung beetles all generate heat to enable greater activity under cold conditions.

    For example. Honeybees generate heat in the winter to keep the hive warm and use heat to kill predatory wasps [sciencenews.org] -- surrounding the wasp, heating up to 45 C (113 F) and killing the attacker.

  • Vehicle knowledge and more. (Score:5, Insightful)

    by Karma_fucker_sucker ( 898393 ) on Monday October 31, 2005 @10:22AM (#13915129)
    "Knowing specific details about the anatomy and physiology of salmon sharks provides key insight into their ability to produce such power and speed during swimming. The knowledge could translate into better designs for underwater vehicles."

    There's so much to learn from our oceans and yet they're disappearing fast because of the need for food and for some really stupid/ignorant [oceansonline.com] reasons. It would be great if more folks would see this as more reasons for onservation and the repeal of the "tragedy of the commons"... I know, in my fucking dreams.

    • There's so much to learn from our oceans and yet they're disappearing fast
      Son, I think you're confusing oceans with rain forests.
    • OK. I'll bite on two items (three if you include a suggestion to RTFA).

      1) How does knowledge of shark muscle performance in low temp give us insight into vehicle technology? Sharks = organic. Vehicles != organic. You can even argue that the hydrodynamics of sharks aren't particularly relevant since they are necessarily adapted to: eating, hunting, and swinging a tail back and forth. (But you'd be partially wrong because the streamlining does work to some extent even if you replace the tail with a prop.

  • But... (Score:3, Funny)

    by sznupi ( 719324 ) on Monday October 31, 2005 @10:23AM (#13915133) Homepage
    What advantege does it give for lasers?

  • Not surprising, and not really "warm-blooded" (Score:5, Interesting)

    by dpbsmith ( 263124 ) on Monday October 31, 2005 @10:29AM (#13915191) Homepage
    The distinction is not between "cold-blooded" and "warm-blooded" animals but between poikilotherms, whose body temperature is the same as that of the environment, and homeotherms, whose body temperature is closely regulated and held within a normal range of a couple of degrees or less

    On the one hand, practically every poikilotherm that's been studied actually thermoregulates in some ways. Very few of them truly assume the temperature of their environment.

    On the other hand, "maintaining" temperature at "68-86 degrees Fahrenheit" -- 77 degrees plus or minus 9--is far from comparable to the degree of thermoregulation shown by mammals. Nine degrees too high or too low is enough to kill you, and most mammals.

    It's interesting to learn how another kind of poikilotherm performs a crude kind of thermoregulation, but by no means earthshaking.
    • Virtually every organism implements homeostasis to some degree. As evolution chugs along, certain mechanisms come into existance that allow them to alter their temperature and other factors as appropriate. The catch is that these mechanisms tend to be expensive (check your heating bill), so there has to be a significant benefit to the organism.

      It's silly to argue that warm-blooded organisms are "more advanced". It simply makes more sense in the context of their habitat, food source, and so on. Stayin

  • I thought there were a bunch (Score:5, Interesting)

    by Nf1nk ( 443791 ) <nf1nk.yahoo@com> on Monday October 31, 2005 @10:30AM (#13915197) Homepage
    As a long time deep sea fisherman I thought there were a bunch of fish who lived with an elivated core temperature. Many of the red meat fast swimming open ocean fish (such as tuna, dorado, baracuda, swordfish) are decidely warm when you pull them in and have a radicaly different muscle structure than what you see with slow moving cold fish. Also the tend to have many fewer visable internal parasites, which I always associated with having a much different metablism.
    • Even great white sharks are. They aren't warm-blooded, but are able to maintain a temperature of ambient + a few degreees by recycling the warm blood from their muscles; like a car's supercharger in effect. Nature has lots of these "inbetweens" when it comes to the warm-blooded - cold-blooded animals. I like this ... not black or white world

    • Re:I thought there were a bunch (Score:5, Insightful)

      by ultramk ( 470198 ) <ultramk@@@pacbell...net> on Monday October 31, 2005 @11:38AM (#13915751)
      You're right, as far as tuna-family fish go at least.

      It's been well-studied that some of the larger species of tuna direct blood that's been heated by the action of their largest swimming muscles to their brain... which helps keep their super-fast twitch-reactions humming. Swordfish use the warm blood to improve their eyesight.

      Mind you, these are some enormous fish. [mbayaq.org]

      m-
    • There was a quite interesting article in the Nov-Dec 2005 American Scientist:

      http://www.americanscientist.org/template/CurrentI ssue;jsessionid=baadyy7MHypG0u [americanscientist.org] (subscription required)

      It talks about how and why tuna and lamnid sharks have elevated muscle temperatures. Has to do with the way they swim. The neat thing is it explains why tuna and these sharks have that stiff-bodied way of swimming. The warm muscles are deep in the body along the spine, but pull tendons that move the airleron-like tail to prop

  • Working muscles give off heat? (Score:4, Insightful)

    by magarity ( 164372 ) on Monday October 31, 2005 @10:39AM (#13915269)
    Since salmon's propulsion muscles are like heart muscles, they never get tired and are always working, doesn't it stand to reason that a muscle that's always working is always generating heat? Expending calories will always have some excess waste heat unless salmon have figured out how to have 100% efficient muscles. So then why is this a suprise?
    • So then why is this a suprise?

      If you even read the summary, you can see it's not about salmon.

      It's about the salmon shark.
    • These sharks, along with makos, tunas and thresher sharks have countercurrent heat exchange vasculature that allows them to maintain elevated body temperatures, so this finding isn't necessarily new. The ability to maintain elevated temperatures often allow these animals to make deep foraging dives into cold water, or, in the case of the salmon shark, live in colder waters. The consequence of cold muscles is that you also move slowly (think of how your hands feel when you forget to wear gloves when it's rea
  • Or at least, can CHOOSE to be. Female rattlers incubating eggs will wrap themselves around the eggs, and 'shiver', to elevate their body temperature to keep the eggs warm.

  • Metric system? (Score:5, Insightful)

    by kjetiln ( 729530 ) on Monday October 31, 2005 @11:33AM (#13915714)
    Could you not use metric temperatures? Celcius is the norm for science. (Kelvin when it is about physics.)

  • tuna also (Score:3, Informative)

    by YesIAmAScript ( 886271 ) on Monday October 31, 2005 @11:44AM (#13915813)
    http://en.wikipedia.org/wiki/Tuna [wikipedia.org]

    Wow, not sure why it is news that some fish are warm-blooded.

    The warm-bloodedness of tuna also makes allows them to be very good swimmers even in cold water.

  • ID vs Evolution (Score:2, Insightful)

    by wpeckham ( 710201 )
    Darned if I see any validity in the way ID and Evolution got into this discussion, but I must comment: Evolution is two things: a theory, and a principal. Both are scientific terms, and have validity only as long as evidence supports them. They describe things known to be true, because Observations from around the world and under different environments support both. Should new observations conflict with some part of either, then our description of them will be modified to fit the new information. Th

    • Re:ID vs Evolution (Score:2, Insightful)

      by jzeejunk ( 878194 )
      I don't know which one is "right". One thing is for sure - evolution favors karmawhores on slashdot. I mean what did the parent say which hasn't been said before and how is it relevant to the article.
  • You've just got to laugh at "scientific" publications that print their data in Fahrenheit.

    How many roods to the hogshead is that anyway?

  • Metric countertranslation (Score:3, Informative)

    by Gorimek ( 61128 ) on Monday October 31, 2005 @03:55PM (#13917945) Homepage
    68 - 86F = 20.0 - 30.0C

    47F = 8.3C

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