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How do leatherback sea turtles stay warm in cold water?

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Illustrations of ten representative chelonians, including spiny softshell turtle, Galapagos giant tortoise, green turtle, alligator snapping turtle, Blanding's turtle, common map turtle, eastern box turtle, eastern painted turtle, spotted turtle, and eastern mud turtle, each labeled with its common and scientific name. A scale bar at the bottom shows size comparison. — turtle Turtles (order Testudines).

Leatherback sea turtles possess unique adaptations that allow them to maintain their body temperature in cold water, distinguishing them from most other modern reptiles which are ectothermic (cold-blooded).12

They utilize several physiological mechanisms to stay warm:

Large Body Size: Their massive size helps them produce and retain body heat.1
Insulation: A layer of fat beneath their carapace provides essential insulation against cold environments.1
Specialized Circulatory System: They possess a network of blood vessels that acts as a heat-exchange system. This mechanism transfers heat produced in the limbs to the blood in their veins, warming it before it returns to the heart.1

These adaptations give the leatherback a near-endothermic physiology, allowing this sea turtle to thrive in temperate and tropical oceans worldwide.12