Early humans ‘may have hibernated through icy winters’, research suggests

Rob Waugh
·2 min read

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 craneum of an adult Homo heidelbergensis, an extinct species of the genus Homo, dubbed 'Skull 4' is displayed at the Museum of Human Evolution (MEH) in Burgos on May 11 2016.   Discovered in July 1992, in the "Sima de los Huesos de los Yacimientos" a cave in the Atapuerca mountainsh, the skull is estimated to be around 430,000 years old. / AFP / CESAR MANSO        (Photo credit should read CESAR MANSO/AFP via Getty Images)
A skull found in 1992 in the Sima de los Huesos, a cave in the Atapuerca mountains in Spain. (Cesar Manso/AFP via Getty Images)

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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.

BURGOS, SPAIN - JULY 16:  Researcher Juan Luis Arsuaga (L) and a colleague enter the archeological site 'Pit of Bones' (La Sima de los Huesos) in Atapuerca Mountains on July 16, 2015 near Ibeas de Juarros, in Burgos province, Spain. Atapuerca Mountains' caves contain human remains from early humans that lived in Europe around a million years ago. The caves also contain the remains of animals that no longer live in Europe, as well as extint species. Although the caves were already documented in the 18th century, the archeological excavations only started on 1964.  (Photo by Pablo Blazquez Dominguez/Getty Images)
Researchers enter the Sima de los Huesos in 2015. (Pablo Blazquez Dominguez/Getty Images)

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."

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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