Most sharks are cold blooded (ectothermic), meaning their body temperature is the same as the temperature of the water around them. Lamnid sharks ( great white, salmon, shortfin mako, longfin mako and porbeagle) can raise their internal temperature above that of the water around them ( endothermic). These sharks have vascular counter-current heat exchangers ( network of blood vessels called retia mirabilia)  that allow them to keep/store the heat generated by their muscles. 

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