Bears do. Bats do. Even European hedgehogs do. And now it turns out that the first humans may have been there too. According to fossil experts, they hibernated.
Tests of bones found at one of the world’s most important fossil sites suggest that our hominid predecessors may have dealt with the extreme cold hundreds of thousands of years ago sleeping through winter.
Scientists argue that the lesions and other signs of damage to the fossilized bones of early humans are the same as those left in the bones of other hibernating animals. This suggests that our predecessors coped with the fierce winters of that time by slowing down their metabolism and sleeping for months.
The findings are based on excavations in a cave called Sima de los Huesos, the pit of bones, in Atapuerca, near Burgos, in northern Spain.
Over the past three decades, the fossilized remains of several dozen humans have been swept away by sediments at the bottom of the dizzying 50-foot axis that forms the central part of the Atapuerca pit. The cave is indeed a mass grave, say researchers who have found thousands of teeth and pieces of bone that appear to have been deliberately dumped into it. These fossils date back more than 400,000 years and were probably from early Neanderthals or their predecessors.
Map of Burgos
The site is one of the most important paleontological treasures on the planet and has provided key information on how human evolution evolved in Europe. But now researchers have made an unexpected turn in this tale.
In an article published in the journal Anthropology, Juan-Luis Arsuaga – who led the team that first excavated the site – and Antonis Bartsiokas, of the Democritus University in Thrace in Greece, argue that the fossils found show seasonal variations that suggest that the bone growth was interrupted for several months each. course.
They suggest that these early humans found themselves “in metabolic states that helped them survive for long periods of time in refrigerated conditions with limited food supplies and sufficient body fat reserves.” They hibernated and this is recorded as interruptions in bone development.
Researchers admit that the notion “may sound like science fiction,” but point out that many mammals, including primates such as bushbabies and lemurs, do. “This suggests that the genetic basis and physiology of this hypometabolism could be preserved in many species of mammals, including humans,” Arsuaga and Bartsiokas state.
The pattern of lesions found in human bones in the Sima Cave is consistent with the lesions found in bones of wintering mammals, including cave bones. “A hibernation strategy would have been the only solution to survive having to spend months in a cave due to icy conditions,” the authors state.
They also point to the fact that the remains of a bear in a hibernating cave (Ursus goodbye) have also been found in the Sima pit, which makes it more credible to suggest that humans were doing the same “to survive the cold conditions and food shortages as the bears in the caves did”.
The authors examine several counterarguments. Modern Inuit and Sami people, although living in cold and equally harsh conditions, do not hibernate. So why the people of Sima Cave?
The answer, according to Arsuaga and Bartsiokas, is that fatty fish and reindeer fats provide food for Inuit and Sami people during the winter and therefore prevent the need to hibernate. In contrast, the area around the Sima enclosure half a million years ago would not have provided anything like enough food. As they state, “The aridification of Iberia could not have provided enough fat-rich food for the inhabitants of Sima during the harsh winter, which led them to resort to hibernation in the caves.”
“It’s a very interesting argument and will certainly stimulate debate,” said forensic anthropologist Patrick Randolph-Quinney of Northumbria University in Newcastle. “However, there are other explanations about the variations that are seen in the bones found in Sima and that must be fully addressed before realistic conclusions can be reached. I don’t think that’s done yet. “
Chris Stringer of the Natural History Museum in London noted that large mammals like bears do not actually hibernate, because their large bodies cannot lower the core temperature enough. Instead, they fall into a deeper sleep known as a torpor. In this condition, the energy demands of the human-sized brains of the people of Sima would have been very large, which would have created an additional survival problem for them during the torpedo.
“However, the idea is fascinating and could be tested by examining the genomes of the Sima people, Neanderthals and Denisovans to detect signs of genetic changes related to torpedo physiology,” he added.