The strange animals that control their body heat

March 2, 2026

Here's something that might blow your mind — some animals can actually control their body heat in ways you'd never expect. Imagine a scientist back in 1774, sweating it out in a room hotter than most of us would dare to imagine. Charles Blagden was thrilled to see his body stay at a steady 98°F, even as the room hit nearly 200°F. Today, we know that most mammals and birds are pretty good at keeping their temperatures stable — it's called homeothermy. But Hannah Thomasy from Knowable Magazine points out some wild exceptions. Take the fat-tailed dwarf lemur — its body temperature can swing nearly 45°F in just a single day. That’s like your thermostat suddenly going haywire, yet the lemur adapts perfectly. So what does this actually mean for us? It hints at some incredible evolutionary tricks and possibilities for future medicine or climate adaptation. And get this — scientists are still uncovering the secrets behind these body heat maestros, as Thomasy highlights in her fascinating report.

In 1774, British physician-scientist Charles Blagden received an unusual invitation from a fellow physician: to spend time in a small room that was hotter, he wrote, “than it was formerly thought any living creature could bear.”

Many people may have been appalled by this offer, but Blagden was delighted by the opportunity for self-experimentation. He marveled as his own temperature remained at 98° Fahrenheit (approximately 37° Celsius), even as the temperature of the room approached 200°F (about 93°C).

Today, this ability to maintain a stable body temperature—called homeothermy—is known to exist among myriad species of mammals and birds. But there are also some notable exceptions. The body temperature of the fat-tailed dwarf lemur, for example, can fluctuate by nearly 45°F (25°C) over a single day.

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