The discoveries in the Spanish cave Sima de los Huesos in the Sierra de Atapuerca have generated an interesting and controversial hypothesis among paleoanthropologists. They hypothesized that the distant ancestors of man, in order to survive during cold and hungry winters, tried to plunge into a kind of suspended animation, prolonged sleep with minimal energy consumption. Let us clarify right away that they did not succeed, but the very possibility of such a procedure without complex technologies does not seem absurd.
The ability to hibernate is also present in large animals, such as bears, and in small rodents, even crocodiles can hibernate by freezing into the ice. That is, people have a genetic basis, a physiological ability to repeat this. The problem is in the conditions of the process - even with a very slow metabolism, the body still expends energy. Therefore, the bear actively feeds itself before hibernation, gains a huge fat reserve, but the human body cannot pull off such a trick.
Fat is extremely important for suspended animation, its deficiency leads to illnesses upon awakening, which is repeatedly observed in the same bears. For a person, this is fraught with rickets, fibrous osteitis, renal osteodystrophy and other dangerous ailments. On the bones of the remains of ancient hominids in a Spanish cave, just such traces were found, plus unexplained signs of explosive growth in adolescents. As if they did not grow for six months at all, and then "catch up" the gap in a matter of months.
The main difficulty of this study is the age of the remains, which exceeds 430, 000 years. These are hominids, but not the fact that they were our direct ancestors. Perhaps, in ancient times, these creatures really gathered on the eve of winter in deep caves with a stable microclimate and covered the whole tribe for several months. This did not work for them, they were very sick after waking up, but this method of wintering allowed them to avoid starvation of most members of the community.