Animals keep food and hibernate for the winter. They escape the cold in a hole. Scientists think early humans also did this. They looked at the bones from our ancestors who lived 430,000 years ago. The scientists know a lot about ancient bones. Cuts and other damage on the bones were like those on the bones of animals who hibernate. Early humans hibernated to escape the cold. Winters were much colder hundreds of thousands of years ago.
There is evidence to show that early humans slowed down their metabolism. They could survive longer in winter without food. Humans could not do this like a bear. Bears can wake up after months of sleeping and their body will be the same. The bones showed that hibernating gave early humans health problems. Many of these were because of not getting enough vitamin D from sunlight. This made their bones weaker.