Some of the ocean’s fastest and most fearsome predators—like great white sharks and tuna—are running hotter than expected, and it’s costing them dearly. New research shows these warm-bodied fish burn nearly four times more energy than cold-blooded species, forcing them to eat more while also struggling to shed excess heat. As oceans warm, this creates a dangerous “double jeopardy”: rising temperatures push them closer to overheating, while shrinking food supplies make survival even harder.