Watch: Early human ancestors may have hibernated the winters away
Could early human beings once have “shut down” in the winter months, hibernating through winter just like bears?
It’s a radical idea, but researchers at the Democritus University of Thrace in Greece say tell-tale damage in bones of human ancestors found in Spain hint that early hominins possessed something akin to an ability to hibernate.
“Shutting down” in this way made the early humans ill, though – with the bones showing that hibernating through months with low food supplies caused kidney problems and other health difficulties.
Researchers Juan-Luis Arsuaga and Antonis Bartsiokas wrote in WIO News that the hominins found themselves “in metabolic states that helped them to survive for long periods of time in frigid conditions with limited supplies of food and enough stores of body fat”.
The researchers found distinctive marks hinting that the early humans suffered from an annual cycle of disease.
The research paper Hibernation In Hominins From Atapuerca, Spain, Half A Million Years Ago was published in L’Anthropologie.
The researchers said in their pre-print paper that this suggests a period of hibernation, Science Alert reports.
The researchers wrote: "We have to emphasise that hibernations are not always healthy.
"Hibernators may suffer from rickets, hyperparathyroidism, and osteitis fibrosa if they do not possess sufficient fat reserves.
“These diseases are all expressions of renal osteodystrophy consistent with chronic kidney disease."
The theory is based on bones found in a Spanish cave known as Sima de los Huesos, the Chasm of Bones.
The deep shaft contains fossils including thousands of hominin skeletal remains from around 430,000 years ago.
The researchers say that bones show signs of Vitamin D deficiency – caused by lack of exposure to sunlight – hinting at prolonged periods inside.
The researchers wrote: "The hypothesis of hibernation is consistent with the genetic evidence and the fact that the Sima de los Huesos hominins lived during a glacial period."
Not everyone is convinced, however.
Forensic anthropologist Patrick Randolph-Quinney of Northumbria University told The Guardian: "It is a very interesting argument and it will certainly stimulate debate.
"However, there are other explanations for the variations seen in the bones found in Sima and these have to be addressed fully before we can come to any realistic conclusions."
Watch: Idaho wildlife cameras capture the moment grizzly bears emerge from hibernating