Bears, bats, and even hedgehogs hibernate to survive the harsh winters. Now, according to fossil experts, it appears that even early humans may have hibernated as well.

According to The Guardian report, from the bones discovered at one of the most important fossil sites of the world suggests that our hominid ancestors "may have dealt with extreme cold hundreds of thousands of years go by sleeping through the winter."

The scientists contend that lesions and other signs of impairment in early humans' fossilized bones are similar to those left in other hibernating animal' bones.

These suggest that early humans survived ferocious weather at that time by "slowing down metabolism," as well as sleeping for several months.

Conclusions Based on the Excavation of a Cave

The researchers' conclusions are based on excavations in a cave known as Sima de Los Huesos, the bones' pit, at Atapuerca, near Burgos, located in northern Spain.

For the last 30 years, several dozen humans' fossilized remains have been scraped from residues discovered at the bottom of the vertiginous 50-foot shaft forming the pit's central part at Atapuerca.

The researchers who have discovered thousands of teeth and bone pieces that appear to have been intentionally dumped there explained that the cave was most likely a mass grave.

Such fossils dated back over 400,000 years and were perhaps from the Neanderthals or their ancestors. This location is one of the most essential palaeontological treasure troves of the planet.

It has also offered key understandings into the manner human evolution progressed in Europe. However, scientists now have produced an unforeseen twist.

Seasonal Variations Shown

In a study published in the L'Anthropologie journal, Juan-Luis Arsuaga, who headed the team that pioneered in the excavation of the site, and Greece-based Democritus University of Thrace's Antonis Bartsiokas, contend that the fossils discovered there exhibit seasonal variations suggesting that bone growth was interrupted for a couple of months every year.

They propose that these early humans found themselves in metabolic conditions which helped them endure long periods of time in freezing conditions. Although they have restricted food supplies, they may have adequate stores of body fat. As a result, they hibernated as evidenced by the disruptions in the development of bone.

The scientists admit that the idea may sound like science fiction, although they point out that a lot of mammals, which include primates like bushbabies and lemurs, are also hibernating.

Arsuaga and Bartsiokas proposed that the inherent "basis and psychology for such hypometabolism could be preserved" in a lot of mammalian species, which include humans.

'Hibernation' Strategy

The pattern of lesions identified in human bones at the Sima cave are aligned with lesions found in hibernating mammals' bones which include cave bears.

In their study, the authors said hibernation strategy would have been the only solution for them to endure many months of stay in a cave because of freezing conditions.

They emphasized, too, the fact that the hibernating cave bear or Ursus deningeri's remains have been also been discovered in the Sima pit. This makes it more credible to propose that humans did the same thing "to survive freezing conditions" and shortage of food as did the cave bears.

Lastly, the authors investigated numerous counter-arguments. Essentially, they found that the somewhat modern Inuit and Sami people, even though they live in harsh, cold conditions, are not hibernating. But evidence point out that those who lived earlier than them in the same area might have.

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