First warm-blooded fish (and we've been eating it for years)

http://www.cnn.com/2015/05/15/opinions/warm-blooded-fish/index.html

Neat article! Thanks for sharing!

Not exactly accurate.  many tuna and the mackerel family sharks are all slightly endothermic.

Bushy

Not exactly accurate.  many tuna and the mackerel family sharks are all slightly endothermic.

Bushy

+1

enjoped recons quote and also true

"It has long been known that certain high-performance fishes such as sharks, tuna, and swordfish can warm some muscles, the brain, or their eyes using a dense web of warm and cold heat exchanging blood vessels around the area in question. However their blood is still cooled to ocean temperature each time it passes the gills, as in all other fishes."

Cool fish! It sounds like they retain a fair amount of heat for a fish, presumably from movement, which is different than the way true endotherms (warm blooded) animals, i.e. mammals and birds, generate heat. To maintain our steady 98.6F in a cooler environment, for example, we can essentially run our cells' engines (mitochondria) without actually doing anything, like an idling car. Fish, on the other hand, sometimes have neat vascular mechanisms called counter-current exchanges to retain/recycle things like heat and gasses. Better than fiction!