Towards an understanding of the costs of fire

Abstract

The ability to produce fire at will and to maintain it for a long duration is considered one of the major advances in human evolution. The exact process by which hominins first learned to use and to create fire is still hotly debated, with some arguing for a sudden transformative event that was quickly followed by a biological and cultural dependence on fire, such as a reliance on the extra calories saved through cooking food and an external source of heat. Others suggest that the 'domestication' of fire was a long and drawn-out process, with hominins using fire when it was available on the landscape but perhaps not having the ability to produce fire until much later in human history. In this paper we propose a third option, that fire should be considered like other technologies-that is, it certainly comes with benefits but also with costs, and that hominins functioned as optimal foragers who chose to use this tool only when the costs were less than the benefits. The potential benefits of fire have been welldescribed in other publications. Here we discuss in detail the various kinds of costs associated with fire and how these costs could, and do, structure human fire-use behavior. We then describe a small experiment to 'put some numbers on' the potential costs of fire, by quantifying one of the most expensive costs (fuel collection) and comparing it to one of the most-praised benefits (cooking of food). The results suggest that the costs of fuel collection are very high in less-forested environments, and that excessively large amounts of cooked foods are needed to match the total costs of fuel collection and the act of cooking. Overall, the costs of fire can be quite high and must be considered when proposing models for pre-modern human adoption and regular use of fire technologies.

Aspects of human physical and behavioural evolution during the last 1 million years

“…The procurement of fuel for fires can incur very high energetic costs, particularly in sparsely forested areas, and therefore the potential benefits of fire would need to outweigh these costs (Henry et al ., ), as has been suggested for the introduction of cooking during the last million years (Carmody et al ., ; Fonseca‐Azevedo and Herculano‐Houzel, ). However, body mass was not found to be a significant constraint in encephalization, but instead was more influenced by foraging efficacy (Cornélio et al ., ).…”

“…In fact, hominins were probably able to obtain the requisite number of calories for encephalization through the consumption of raw, rather than cooked, meats (Cornélio et al, 2016). The amount of cooked meat that would be required to counteract the effect of potentially costly fuel procurement was extremely high, indicating that creating fire may not have been a consistently beneficial strategy (Henry et al, 2018).…”

The use of ash at Late Lower Paleolithic Qesem Cave, Israel—An integrated study of use-wear and residue analysis

“…The adaptive role of fire in human evolution has inspired a rich archaeological debate focused on “when” and “where” fire had originated, as well as its benefits in facilitating light, heat, security and other aspects of human life [ 1 – 3 ]. The general use of fire is commonly dated back to the Early-Middle Pleistocene [ 4 , 5 ] whereas the habitual use of fire seems, at large, to have emerged during the later Middle Pleistocene [ 6 , 7 ].…”

The Significance of Air Circulation and Hearth Location at Paleolithic Cave Sites

“…However, recent studies have also pointed out the possible drawbacks of using fire on a daily basis. Hearth maintenance demanded significant investment of energy for tasks such as wood collection and storage (Goudsblom 1992;Henry 2017;Henry, Büdel & Bazin 2018;Mallol & Henry 2017;Pryor et al 2016;Twomey 2014). In addition, gathering around the hearth might have contributed to the spread of disease (Cisholm et al 2016).…”