Great whites' warm-blooded edge becomes liability as oceans heat up

Great white sharks and other mesothermic fish-species that maintain body temperatures above surrounding seawater-face a physiological squeeze as oceans warm, according to new research in Science led by Trinity College Dublin’s Nick Payne. The same evolutionary trait that enabled their speed, predatory success, and long-distance migrations now threatens to cook them from the inside as climate change pushes ocean temperatures higher.

These species, which represent under 0.1 percent of marine life and include great whites, basking, thresher, and porbeagle sharks plus large tunas, burn roughly four times more energy than cold-blooded fish. The heat-retention problem worsens with body size: larger animals generate metabolic heat faster than they can shed it. Compensating behaviors-slowing down, redirecting blood flow, or diving deeper-all come at a cost while prey becomes scarcer due to overfishing.

The result is what researchers call “double jeopardy”: shrinking thermally suitable habitat combined with declining food supply. Expect range shifts toward cooler waters, intensified competition during summer months, and continued population pressure on apex predators whose ecological role is difficult to replace.