Energy Use by Eem Neanderthals

A paper in the Journal of Archaeological Science by Bent Sørensen of the University of Roskilde in Denmark, discusses how European Neanderthals living in the Eemian interglacial, dated to around 125,000 years bp  might have Neanderthaler fitted clothesconserved much needed energy by drying and storing meat,  wearing fitted clothing, and sleeping beneath blankets of mammoth skin, behaviours that would have greatly increased their chances of surviving decreasing temperatures with the onset of ice ages.

Because Neanderthals were far more robust than ourselves and experienced lives of great physical duress, energy acquisition and conservation would have been of prime importance to them, especially when we consider that hunting trips in pursuit of large herbivores would have involved the physical challenges of attacking the prey at close quarters,  transportation of large quantities of meat back to camp  – drying large quantities of freshly killed lean meat greatly reduces the weight burden, and moreover prevents it from quickly rotting. Fatty meat on the other hand does not preserve well, and rots more quickly than lean meat.

The paper also presents a good case for the idea that contrary to many depictions of barefooted archaic humans draped in ill-fitting animal skins, (which would have afforded little in the way of protection from the elements) it seems more likely from the scarce archaeological evidence, that they wore clothes that fit and sturdy foot-wear to boot. Not only would this have been the case during colder glacial eras, but also during warmer spells, when sleeping at night would have required the use of covers or blankets, when night-time temperatures would have dropped.

Abstract:

An analysis of energy use by Neanderthals in Northern Europe during the mild Eem interglacial period is carried out with consideration of the metabolic energy production required for compensating energy losses during sleep, at daily settlement activities and during hunting expeditions, including transport of food from slain animals back to the settlement. Additional energy sources for heat, security and cooking are derived from fireplaces in the open or within shelters such as caves or huts. The analysis leads to insights not available from archaeological findings that are mostly limited to durable items such as those made of stone:

Even during the benign Eem period, Neanderthals faced a considerable heat loss problem. Wearing tailored clothes or some similar measure was necessary for survival. An animal skin across the shoulder would not have sufficed to survive even average cold winter temperatures and body cooling by convection caused by wind. Clothes and particularly footwear had to be sewn together tightly in order to prevent intrusion of water or snow.

The analysis of hunting activity evolvement in real time further shows that during summer warmth, transport of meat back to the base settlement would not be possible without some technique to avoid that the meat rots. The only likely technique is meat drying at the killing site, which indicates further skills in Neanderthal societies that have not been identified by other routes of investigation.


Although only the abstract is available at the Journal of Archaeological Science, the paper is reproduced (PDF) in its entirety at Professor Sørensen’s website, affording us the opportunity of gleaning further insights into the lives of Neanderthals living in north-western Europe 125,000 years ago, a time when the climate is estimated to have been fairly similar to the current conditions, and one that was capable of supporting plenty of food on the hoof, and extensive woodlands which in turn allowed Neanderthals to exploit timber, not only as fuel for the fire, but quite possibly for the occasional hut as well – suggestions that they built wind-breaks for example, is further testament to their technological prowess.

Additionally, consideration is given as to how they would have coped with the cold during long glaciations, when the fauna they hunted would have changed, focussing more on mammoth, which appear to have been virtually absent from this part of Europe during warm intervals. Here’s an excerpt from the paper addressing this very topic:

The minimum endurable temperature calculations presented in Table 1 show, that sleeping naked in a cave or hut (sheltered from wind) requires temperatures above 27 or 28 °C (male and female), and 5 °C more if sleeping outside, even in a place with low wind (1.5 m s-1). Wearing one layer of clothes, the minimum endurable temperatures change to 13 and 15 °C inside, 16 and 20 °C outside, and with a mammoth-equivalent skin cover to –15 and –10 °C inside and -9 and –4 °C outside in a 5 m s-1 wind. Clothes plus mammoth-equivalent skin cover lowers the endurable temperatures by another 13-14 °C.

The implication is that bed cover equivalent to a large mammoth skin would have been indispensable at nearly all times during the year, and that hunters on a multi-day winter hunting expedition would have had to bring some form of cover to use when sleeping along on the trip. Exposed body areas such as the face would need heat transfer from adjacent areas. Extremities are more cold-sensitive than the whole-body average, and only small exposed areas would receive enough heat transfer from covered parts of the body. Thus, the conclusion drawn is that in average winter conditions, the clothes worn must have been capable of preventing air flow from penetrating to more than small body surface areas, and that footwear in particular must have been tailored to wrap the feet entirely during the long walks associated with day-long hunting trips.

Lithic remains from the Eem include awl-like points suited for making holes in skin material (found e.g. at the Stuttgart-Untertürkheim site; Wenzel, 2007), as well as knife-like blades suited for cutting strips of animal skin, that could be inserted and weaved through the holes, in order to convert plain furs into fitting clothes.

The last paragraph details the use of stone blades and awls, and despite a recent story which asserted that the earliest known stone blades date back half a million years, it transpires that both stone blades and awls are associated with Oldowan and Acheulean lithic industries, which also included scrapers, all of which could have been used in the treatment or modification of animal hides.

Although the necessary tools may have been available, this doesn’t necessarily mean that archaic species such as H. erectus definitely made their own clothes and shoes, but if they had already lost their body hair, sleeping under covers at night would have been just as necessary for them as their Neanderthal descendants. It may well have been that the first clothes were invented after archaic humans had realised that the material used for their nocturnal coverings could be further modified and stitched together to make the first clothes – it would have been apparent from very early on that simply draping themselves with animal hides would have been more a hindrance than an aid to survival. Whether aesthetic factors were also involved, isn’t known…….

The question of the earliest footwear has been addressed amongst others by Erik Trinkaus, who suggested that the appearance of more gracile toe-bones found with dated human fossil remains, seen at around 30,000 years bp, possibly earlier, indicated that people first began wearing shoes or boots at that time. However, there doesn’t appear to have been any reduction in the size of Neanderthal phalanges that would support this theory,which holds that shoe wearers use their big toe to gain traction, passing less energy through the four smaller toes, leading to a decrease in their size.

This story also receives coverage over at Discovery, and the article there includes further musings and a few quotes from Bent Sørensen:

According to the study, Neanderthals sported “one or two layers of skins/furs and wrapped skins/furs for shoes, held together by leather strings.”

Author Bent Sorensen told Discovery News that chewing clothing materials wasn’t beneath these members of the Homo genus.  “Neanderthal tooth marks indicate chewing hides for softening, which is essential for clothes making,” said Sorensen, a researcher in the Department of Environmental, Social and Spatial Change at Roskilde University.

Using the body surface area of Neanderthals, based on their skeletal remains, along with known climate condition averages for Northern Europe at the time, he calculated the metabolic body energy required to compensate for energy losses during sleep, daily settlement activities and hunting expeditions.  Even with warm fires lit in caves and at other home sites, Sorensen believes Neanderthals must have slept underneath mammoth skins and other coverings.  Tools found for making clothes, such as hide scrapers and points for poking holes in animal skins, support his contention that Neanderthals dressed in well-fitted layers.

And on the subject of how and why Neanderthals might have dried fresh meat:

Taking into consideration basic movements needed for hunting and survival, such as walking and wood cutting, Sorensen believes Neanderthal groups would have needed about 1,792 pounds of meat per month, requiring one mammoth — or other big game kill — every seven weeks.  Animal bones and stone tools at Neanderthal sites indicate they hunted away from home. In order to transport meat, Sorensen thinks they must have dried it somehow. But, he said, “I do not know of any evidence for (them) using salt.”

“As for preparation, boiling is much more efficient and nutrient-conserving than frying, and evidence from more recent Stone Age settlements confirm that meat was boiled in ceramic pots or skin bags,” he said. “However, it is still likely that frying over the camp fire was the usual method in Neanderthal communities, since no containers for boiling have been found.”  “Carrying dried meat from a mammoth home could now be done by seven to eight round trips (over) 14 to 16 days,” he added.

This last observation depicts Neanderthals as spending much of their precious time lugging heavy loads across the landscape, chopping and gathering timber when climate permitted, as well as much time and effort preparing animal hides by chewing, rather than living an idyllic lifestyle of nomadic people hunting and gathering plentiful supplies of food, leaving plenty of time on their hands for recreational activities.

Moreover, had Neanderthals used salt for drying the meat, they would not only have needed access to rock salt deposits, but would have needed to transport it in bulk to kill sites, which would further have expended their energy, so I’m not sure if salt was the solution. Although there are rock salt deposits in Germany, Austria and Poland, I’m not aware of any archaeology which demonstrates Palaeolithic exploitation of this resource, and in any case, only groups living nearby would likely have been able to make use of whatever they found to hand. It’s generally thought that Neanderthals groups lived in relative isolation to one another, meaning that salt was unlikely to have formed part of a trade network, not least because regular transportation in quantity would have required the use of animals to carry it.

Drying large quantities of meat with smoke would have required intense activity at the kill site, the erection of a wooden structure and construction and maintenance of a fire would have required a hypothetical hunting party of 5 or 6 people to have set up a secondary kill-camp, thus expending more energy, which in turn would have been supplied in part from fatty meat from the kill which would presumably have been eaten instead of the lean cuts set aside for drying. Smoke from a small camp fire wouldn’t have been sufficient for drying out the meat from a mammoth for example.

The least labour intensive methods of drying meat would have been sun and wind, involving the building of wooden frames or structures on which to place it, but of course local weather conditions would have dictated how often and for how long this would have been a viable option.

The suggestion that Neanderthals made their own fitted clothes and kept food in storage rather than eating as much as they could on the spot, before heading off in search of the next meal, certainly seems to indicate complexity of thought that allowed for long-term planning and innovatory behaviours  – and as we have seen from previous reports, they made a type of adhesive from heat-treated birch resin around 80,000 years ago, with which they may have hafted their hunting spears.

Over recent years the perception of Neanderthals has significantly altered, with strong indications that they may have been just as adept at survival as their anatomically modern counterparts, with one or two key differences that may have caused their downfall.

As mentioned in the paper, Neanderthals weren’t capable of throwing spears, which meant that big game had to be tackled close up, increasing  the risks of injury and death over someone launching a spear from a relatively safe distance, but the energy expenditure would also have been considerably greater. This might not have been to detrimental in the absence of competition, but once that competition arrived in the guise of anatomically modern humans (AMH), it’s likely that the balance tipped in favour of the moderns.

Not only would AMH have had to spend less energy hunting, but it would also have been relatively easy for AMH to rob Neanderthals of their own food. In the paper, Sørensen proposes a model for Neanderthal groups and their seasonal hunting and gathering activities. The basic group might have comprised 25 people, of which about 15 would have been children, leaving about 5 or 6 individuals available for hunting trips, who exploited territories of between 10 and 50 square kilometers. Seasonal base camps would have been established, with fresh or dried meat being transported from kill sites, meaning that rather than being nomadic, the Neanderthals would have relied heavily upon the same resources being in place at the same stages of each year, every year. Climate change might have been quick, but presumably slow enough for Neanderthals to adapt and survive.

Greater problems may well have arisen with the advent of AMH at the same time as climate change as Upper Palaeolithic cooling kicked in, meaning that not only would Neanderthals have been obliged to alter their own hunting strategies, but they found themselves in competition with AMH for the prime sites. We can imagine how the somewhat rigid strategies of Neanderthals would have made them vulnerable to being out-hunted by AMH, and at risk of ambush when guarding or transporting freshly killed meat. The fact that AMH could have thrown spears not only at prey but Neanderthals too would have given them a doubly competitive edge, and although such events may have been rare at first, over the course of about 15,000 years that AMH and Neanderthals shared Eurasia, deteriorating climate and AMH populations which were increasing, could between them have been major contributory causes in the downfall of Neanderthals.

Demography and the Extinction of the European Neanderthals (PDF) is another paper by Professor Sørensen, which addresses these and other potential factors as disease, spread by AMH and transported by migratory groups of Neanderthals, and provides yet more food for thought for those attempting to explain the mysterious demise of our enigmatic cousins.

References:

Energy Use by Eem Neanderthals by Bent Sørensen, Department of Environmental, Social and Spatial Change, Roskilde University, DK 4000 Roskilde, Denmark, Journal of Archaeological Science Article in Press, Accepted Manuscript, 2009.

Demography and the Extinction of the European Neanderthals by Bent Sørensen, Department of Environmental, Social and Spatial Change, Roskilde University, DK 4000 Roskilde, Denmark.

image from: A Brief History of World Costume

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