Did you know that salmon sharks can elevate their body temperature above that of the surrounding water?

salmon shark
salmon shark ©TOPP Tagging of Pelagic Predators

Using counter-current heat exchangers that allow them to retain the metabolic heat generated in the muscles, viscera, kidney, and brain (like in the paws of the snow fox, for instance) they can maintain their body temperature above about 70ºF in waters as cold as 35ºF. Their hearts are built to provide their tissues with enough oxygen to stay active in cold environments, but they also roam between Alaska, Hawaii and California.