Why Don’t Humans Hibernate? An Evolutionary Biologist Explains

InnovationScienceWhy Don’t Humans Hibernate? An Evolutionary Biologist ExplainsByScott Travers,Contributor.Forbes contributors publish independent expert analyses and insights. I write about biodiversity and the hidden quirks of the natural world.Follow AuthorMay 08, 2026, 08:30am EDT--:-- / --:--This voice experience is generated by AI. Learn more.This voice experience is generated by AI. Learn more.You may not know that our ancestors hibernated during the winter months. Why did we evolve out of this biologically prolific survival mechanism?gettyDeep inside a limestone cave in northern Spain, researchers made a discovery that upended what we thought we knew about our own ancestors. The bones — 430,000 years old, pulled from a shaft called Sima de los Huesos, or “the pit of bones” — were riddled with a very specific kind of damage. Tunneling through the trabecular structure. Lesions consistent with seasonal metabolic shutdown. Bone signatures, in other words, that look strikingly like those left on animals that hibernate.The implication was difficult to sit with. Early hominins, our own relatives, may have once curled up and gone dormant for the winter. A 2020 paper published in L’Anthropologie by paleoanthropologists Antonis Bartsiokas and Juan-Luis Arsuaga made the case: lesions on the fossils, including subperiosteal resorption and rickets-like deformities concentrated in adolescents, mirrored the bone pathology of hibernating cave bears found in the same deposit. These were the physiological signatures of a body that cycled through months of metabolic near-silence.And yet, you know today that no matter how harsh winter is, you won’t be shutting down for the season. So, somewhere between then and now, evolution ruled hibernation out for us. To understand why, we need to understand the process of hibernation first.What’s Happening In Bodies That Hibernate?The science of hibernation is more sophisticated than its reputation. It is not sleep, not even close. True hi...