

Scientists have discovered a warm-blooded fish - davidst
http://www.washingtonpost.com/news/energy-environment/wp/2015/05/14/scientists-have-discovered-the-first-warm-blooded-fish/

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oofabz
This fish is not "fully warm-blooded". As described in the article, it does
not target a specific body temperature like mammals or birds. It just uses its
muscles to warm itself, like some species of snake and insect do.

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bobbles
Does targeting a specific temperature determine if you're classed as warm
blooded?

Relevant article snippet:

"Some other types of fish, such as tuna, have similarly designed blood vessels
in certain parts of their bodies, allowing for “regional endothermy” — warm-
bloodedness that’s limited to certain organs or muscles, such as the eyes,
liver or swimming muscles.

But the opah is the only fish scientists know of that has this design in its
gills, where most fish lose the majority of their body heat to the surrounding
cold water. By warming up the blood in the gills before it goes anywhere else,
the opah achieves not just regional endothermy, but whole-body endothermy,
according to the paper’s authors.

Testing showed that the opah is able to maintain a core body temperature about
5 degrees Celsius warmer than the surrounding water."

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NickNameNick
The nice thing about warm-blooded animals targeting a narrow body temperature
range is that our genetic and protein structures can be much simpler.

A cold blooded animal has to have a wide selection of proteins to do the same
job at different temperatures. A warm blooded animal needs just one.

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sitkack
Air cooled Volkswagen tolerances.

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keithgabryelski
meh, this seems to be equivocation. basically, warm blooded (and cold-blooded)
are no longer used (because they found animals didn't cleanly fit into the
features of each), so they have a bunch of other words that describe the
components of blooded-ness -- like, does the animal maintain a specific body
temperature, does it use heat to convert sugars into (ATM) energy. What
they've found is the first fish to warm water on entry to gills so that THAT
water doesn't bring the temperature of the fishes body down too low.

meh

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DougBTX
Basically yes, though according to the article the fish is heating cold blood
with warm blood, not the water passing through its gills.

Like birds legs: [http://askanaturalist.com/why-don’t-ducks’-feet-
freeze/](http://askanaturalist.com/why-don’t-ducks’-feet-freeze/)

