Salmon sharks are warm blooded and can stand temps down to about 36 degrees. I wonder if they have any adaptations in their gills to prevent heat loss or if they don’t care because they warm their bodies.
> It is known for its ability to maintain stomach temperature (homeothermy), which is unusual among fish. This shark has not been demonstrated to maintain a constant body temperature.
https://en.wikipedia.org/wiki/Salmon_shark
But there is indeed a vascular heat exchanger involved:
The shark can raise its body temperature 14-20 degrees more than the environment. I think it fits the definition of warm blooded.
I used to be able to do homethermy by thought when I was younger... but I have lost the ability.
(SERIOUS); I used to be able to direct heat to various extremities by thought when I was laying in bed in really cold environs... but I seem to have lost that ability.
Or, you can also use WinCompose (or Xcompose for X Windows users. For tty users, tough luck). At least, on my installation, it can be typed as "Compose Compose d e g f".
My assumption is the skeleton, marrow and body fat (or some other body structure with high thermal mass) act as a heatsink that expels some built up heat.
cartelige is a permeable material for various occupants, oxigen being one.
So we find that highly oxigenated creatures are larger and more carnivorous
we also know that high ingestion of oxygen results in larger creatures
so if a shark has a larger ability to permeate oxygen into the muscles and have the ability to store heat, plus the ability to transfer heat/oxy btwn bodies...
This is why we can see a body +500 years old..
buoyed by the buoyancy of less dense bones, such as cartilage.