The Middle Pleistocene (125,000-780,000 years ago) was marked by periodic oscillations between a climate similar to today’s and much cooler phases, [according to new research] published in the Journal of Human Evolution.
[H]umans had to withstand very low temperatures during this period and, surprisingly, not only during the glacial phases, but also at milder times, even at places in the Iberian Peninsula such as Ambrona or Atapuerca.
“That humans were able to endure such harsh conditions is difficult for us to imagine if we bear in mind that evidence for the use of fire in Europe during this period is extremely sparse. In fact, many researchers think that they were not capable of generating and using fire habitually,” explains [researcher Jesús] Rodríguez.
Exposure to cold, especially at night, would represent a real challenge for thermoregulation. There is a limit to the metabolic response cold temperatures at night elicit, but where physiological mechanisms do not reach, human behaviors can plug the gap, as [researcher Ana] Mateos says:
“They could put up with very low nighttime temperatures if they slept covered in furs, especially if they did this as a group in a spot where they were sheltered from the wind.”