As oceans warm due to climate change,'mesothermic' species, known as “mesotherm” species, which maintain warmer body temperatures than surrounding seawater, are at risk of overheating due to warming oceans and declining food due to overfishing. These species are burning four times as much energy as their cold-blooded counterparts, whose body temperatures match the surrounding water. As water temperatures rise, these species will be forced to relocate to cooler waters. The study suggests that these species must slow down, alter their blood flow or dive to cooler temperatures, while hunting for an ever-dwindling food supply. Researchers used tiny sensors on a range of fish, including basking sharks weighing over 3 tons, to measure how much heat fish produce and lose in real time. They found that a one-ton warm-bodied shark may struggle to remain in waters above 62.6 degrees Fahrenheit (17 degrees Celsius) without taking counter measures. The discovery of these "hidden heat budgets" could prove crucial for conservation efforts or mapping protection areas.