Post by Admin on Oct 23, 2019 7:35:37 GMT
DISCUSSION
Taking into account the scarcity of postdepositional taphonomic damage and the low influence of mineral density-mediated attrition processes at Qesem, the hominid transport decisions and the ravaging by carnivores were considered as candidates in the search for the main factors to explain the bias of the anatomical profile [e.g., (15, 16)]. Destruction and subsequent ravaging are closely linked to the mineral density of the bones and their portions in the case of carnivores [e.g., (17, 18)]. For example, Madrigal and Holt (19) argued that if the limb bones are processed, the isolated shafts tend to survive carnivore ravaging, while cancellous bone portions will be removed by ravaging carnivores. The scarcity of the epiphyses of long bones, especially the least dense epiphyseal portions, such as the proximal humerus, distal femur, and proximal tibia at Qesem, could raise the possibility of carnivore attrition. However, an underrepresentation of spongy bone is not necessarily only due to carnivore attrition but may be also the result of other causes, including anthropogenic processing, such as bone grease production, or the use of bone as fuel (20). As argued in several previous works, the impact of carnivores on the faunal assemblages at Qesem is minimal [e.g., (15, 16)]; thus, the inspection of the relationship between the anatomical profile and the economic utility of elements in this case becomes relevant to the assessment of economic transport strategies.
The skeletal representation at Qesem is biased toward the high utility elements, with a predominance of limbs and mandibles compared to skulls and axial bones. The ungulate body part profile correlates positively with the UI bone marrow and UMI, pointing to the importance of marrow in hominin transport decisions. However, some specific differences between weight sizes are worth highlighting, since they precisely relate to the representativeness of the metapodials. The %MAU shows very low proportions for the metapodials of large-sized ungulates (e.g., aurochs and horse) with values between 0 and 9.7%. The trend changes completely in the case of small- and medium-sized species (e.g., fallow deer and red deer) with percentages between 65.4 and 84.6. This composition was already detected in the faunal assemblage of the central hearth area and interpreted on the basis of ethnographic parallels once postdepositional processes and carnivore ravaging were ruled out (16). According to some modern ethnographic descriptions, the pattern of disarticulation is highly variable among different hunter-gatherer groups and species. Domínguez-Rodrigo (21) documented an example of variation in the pattern of dismembering in the case of the Maasai people, which differs from the one observed by Gifford-Gonzalez (22). The ethnic group from Peninj (Tanzania) usually severs metapodials from the limbs after the first step of skinning; however, the Massai from the south-east of Kenya remove complete limbs first (without disarticulating them) after evisceration. Among the Hadza or the San, it is repeatedly observed that the preparation of carcasses for transport may involve the consumption of some viscera and marrow from long bones, especially in large ungulates (21, 23). These episodes would lead to the breaking of some marrow-rich bones, such as the metapodials, at the kill site or hunting stations for marrow extracting and immediate consumption. This internal resource would provide an extra nutritional supplement for hunters while they process the carcass and prepare it for transport (7, 24). Marrow extraction is a low-cost activity relative to fat removal in that it only requires a few minutes to completely process a bone, particularly if the bone is not covered by flesh, as is the case of metapodials (17). This phenomenon could explain why the metapodials of large-sized ungulates at Qesem were scarce compared to the quantity of the rest of the limb bones. That is, the initial consumption has been able to condition the variety of bones that were transported to the base camp. A carcass can be conceptualized as a patch of skeletal elements, each with a pursuit and handling cost (25). Nevertheless, we must take into account that other variables could also affect transport decisions and generate different body part profiles, e.g., the distance from the hunting area to the home base, the number of animals harvested simultaneously, the number of participants in the hunting party, the location and time of day when the animals are acquired (e.g., 26, 27), the technological state of development (28), the condition of the animals (7), and the risk of predation by other carnivores (29). The dynamics of carcass transport are complex, and although the degree of difficulty is evident and can vary with each carcass or situational event, major trends can emerge.
O’Connell et al. (30) documented that the abandonment or processing of some limb bones at kill sites is often contingent on prey size. The metapodials of small- and medium-sized ungulates are well represented in both the Amudian and Yabrudian of Qesem Cave contexts, and they correlate with the other limb bones, showing relatively similar quantities. Thus, there seems to be a differential treatment according to weight size as a general trend in Qesem, where small- and medium-sized animals are mainly transported as field-butchered units to base camp. The presence of transverse cut marks on the basipodia and proximal epiphyses/metaphyses of the metapodials suggests that they were almost systematically separated from the intermediate appendicular bones (radius-ulna and tibia). This butchery pattern seems similar to that performed with the metapodials of large-sized ungulates at the kill sites, but now it was performed at the cave after the limb bones were transported whole. However, how can we know if skinning and bone breakage (and the subsequent marrow consumption) were immediate or delayed?
The metapodials of medium- and small-sized animals show the typical signs of intentional percussion to access the marrow, and therefore, a priori, we could consider immediate consumption of the marrow as a snack or additional nutrient during processing or as one of the final stages of the sequence after the extraction of the animal’s external resources. However, our experimental series do not show any differences in the morphology or location of the notches during the first 2 weeks of exposure that would enable us to identify whether the consumption was immediate or slightly delayed. The notable difference takes place from the third week onward, when the notches are less well defined and are replaced by percussion pits associated with cortical flaking and longitudinal or slightly curved fractures. Given the high level of bone fragmentation in the Qesem assemblages, and because of anthropogenic and postdepositional processes (different types of pressure loading, such as trampling and/or soil compaction), metapodial fragments do not always register the impact points (notches or pits), and therefore, our attention must turn back to the fracture planes looking for clues to the condition of the bones at the time they were broken for marrow extraction.
By applying the criteria of Villa and Mahieu (31), the metapodials in Qesem appear to mainly register characteristics of a fresh fracture, with a preference to oblique angles, longitudinal delineations, and smooth surfaces. However, these bones can remain fresh over time, as they maintain not only their collagen in high proportions but also their nutritional values, such as fat and protein (32). In relation to this, the analysis of the fractures in the experimental series revealed that the angles, outlines, and surfaces were similar to those generated by fresh breakage even in weeks 6 to 9 in natural outdoor conditions (scenarios 1 and 2). At this point, we needed to explore more variables.
Obviously, before the metapodials were fractured, they had to be skinned. The cut marks could provide us with data on the state of the skin when it was removed, since the effort to remove this tissue varies depending on whether it is fresh or dry, a circumstance that would also result in a different taphonomic signature. The same situation can be observed when the dried flesh is removed from the bone because the cut marks’ frequency and morphology can vary depending on factors such as the state and weight of attached flesh at the time butchery is undertaken [e.g., (33)]. Dry flesh is more attached to the bone, which is why more effort is required to remove it than when it is fresh, as is the case when the tool reaches the muscular insertions or tendons firmly attached to the bone. This leads not only to a greater number of marks but also to a different pattern with different morphologies and orientations from those observed in the defleshing of large, fresh muscle bundles or when the butchery is performed with a specific purpose, such as extracting long cuts or slices of flesh of roughly standardized shape (i.e., fillets) for drying [e.g., (34)].
Longitudinal and oblique incisions on the lateral sides of the metapodials similar to those that would occur when the skin is in a fresh state have been identified in Qesem. These marks were also occasionally observed in the experimental series, although they were only recorded in the first week of exposure. From the second week, the short (shallow and deep) incisions and sawing marks were predominant, with special relevance on the anterior and posterior surfaces (where the tendons are found), and it is from the fourth week onward that the number of these marks increased along with a variation in the inclination of the sections toward an almost flat oblique position. These types of marks are precisely the ones that predominate in Qesem (77.9% of the anterior/posterior surfaces of metapodial shafts showing cut marks), which would lead us to consider a possible delayed secondary skinning (by at least 2 weeks according to our experiments). Nevertheless, despite the similarity to the experimental marks, we cannot rule out equifinality, i.e., other processes could produce similar cut marks. For instance, we cannot rule out the existence of cultural patterns in processing techniques that give rise to marks with these characteristics. These specific “ways of doing” could be perpetuated over time and materialize in the archaeological record in patterns or in what Yellen (26) called “style” in the butchery among the!Kung Bushmen. However, other types of marks that could be diagnosed with possible secondary processing exist. These are the cortical scars associated with chop marks (or chipped marks), which are sometimes combined with prominent incisions and sawing marks on the anterior/posterior side, showing the same orientation and inclination almost parallel to the bone. These marks were also sporadically generated at the experimental level from the second week and systematically from the seventh week in scenario 1. This atypical damage was caused by the difficulty of removing the dry skin and tendons that remained strongly attached to the bone after outdoor exposure. The presence of these alterations does seem to suggest that some Qesem metapodials could have been processed subsequently (after 2 to 7 weeks), and it also makes the previous type of marks more relevant for this interpretation.
According to the nutritional analyses of the experimental sample, the marrow of the metapodials was conserved in good condition in the outdoor autumn scenario (scenario 1), preserving useful nutrients until the ninth week; however, in the indoor and outdoor spring series (scenarios 2 and 3), the marrow showed a significant decrease week by week, which was particularly noticeable from the third week. Thus, seasonality seems to be an important variable when assessing marrow degradation. This fact is interesting because in Qesem Cave, seasonal hunting peaks have been detected that specifically include late summer through autumn, during and/or after the rutting time (16, 35).
From a microbiological perspective, the delayed consumption of marrow also seems to be relatively safer than consuming dry meat, since the marrow remains encapsulated by the bone, offering protection against microbes, even when the bacteria have been injected into the circulatory system and have reached the marrow via the nutrient artery (9). The study by Smith et al. (9) showed that, in raw meat, all bacterial populations grew rapidly within 24 hours; in contrast, the number of colony-forming units in samples taken from marrow inside the bone was consistently low.
Apart from bone coverage, the skin could also provide insulation or have a protective effect against insects and/or bacteria. Insects play an important role in carcass decomposition processes. By transporting microbes and producing young that tunnel and aerate the tissues of the carcasses, insects alter the microbial and physical nature of the carrion in such a way that they promote bacterial growth (36). In the case of the metapodials, the skin and tendons are in direct contact with the bone, and in the absence of soft tissues (such as flesh) susceptible to being rapidly colonized by bacteria, they could offer preservation advantages in the case of outdoor exposure. Although this hypothesis seems logical, the truth is that in the experimental level, the metapodials exposed without skin in scenario 3 did not show statistically significant differences in nutritional degradation compared to those exposed with skin. Despite this, during the preparation of samples for chemical analysis, a different aspect was detected in the marrow that came from the skinless metapodials, which had a more gelatinous, harder, and pinker appearance. In any case, Qesem’s metapodials register marks that indicate that they were accumulated with skin to be processed secondarily and later in time in an attempt to preserve the bone marrow.
Accumulating bones for delayed consumption of grease and marrow has been documented ethnographically among Nunamiut Eskimo communities, where the bones are stored during the winter months to be processed in large batches (1). The Loucheux people also process the bones secondarily and with a slight delay, although normally they do not exceed 3 days of outdoor exposure; once the grease/fat is extracted, these groups store it inside the stomach of caribou (converted into bags), where they claim that it stays in good condition for 2 or 3 years (24). Another example of the use of ungulate organs to store bone grease after rendering comes from the Comanche and Blackfoot people, who store dried meat mixed with bone grease and marrow in stomachs, intestines, and rawhide bags sealed airtight with tallow [e.g., (37)].
Ethnographic studies have shown that a significant number of nonagrarian peoples engage in some sort of delayed consumption [e.g., (38)]. This practice often requires the development of preservation techniques (mainly in the case of meat), which can vary depending on factors such as geographical area, environmental conditions, seasonality, and/or technological capabilities [e.g., (39–41)]. Drying meat under natural temperatures, humidity, and air circulation, including direct sunlight, is perhaps one of the simplest methods. This presumably applies to smoking too, as it also involves the removal of moisture from the meat (40). Smoking meat has an added preservative effect, apart from surface drying, in that the smoke from the sawdust contains bactericidal agents, such as formaldehyde, and also inhibits fat oxidation (41). During colder seasons in northern environments, freezing is another method that would allow preservation of internal and external resources (i.e., meat and fat/grease) without much effort, permitting entire articulated carcasses (or with minimal field butchery) to be cached after skinning and gutting (39).
Hunter-gatherer food storage is considered a “risk-reducing mechanism” designed to offset seasonal downturns in resource availability and is typically seen as evidence of intensified subsistence activities [e.g., (42)]. Recently, Speth (43) argued the potential use of fermented and deliberately rotted meat and fish in forager diets throughout the arctic and subarctic, concluding that putrefied food was widely used as a desirable and nutritionally important component of human diets (and not solely as starvation food). Fermentation is a widespread technique used for food preparation and preservation. These types of “processed” foods can also have dietary benefits and are even considered delicious (instead of unpleasant) by people who grow up eating them (44). Speth (43) extended this approach to the Eurasian Middle Palaeolithic hominids who inhabited analogous environments, suggesting the possibility of delayed consumption among the Middle and early Late Pleistocene populations. At this point, it can be assumed that bone marrow could also have been part of this pack of resources susceptible to being processed secondarily over time. Marrow FA composition evolves with time of conservation, showing a decrease of monounsaturated FAs presumably due to its oxidation into shorter chain products, including dicarboxylic acids and short-chain FAs. These products could make fats taste and smell rancid. It is difficult to know if this rancidity could have impaired the consumption of aged marrow, but, as in the case of dry meat, we could assume that the preference for this type of aging depends on the consumer and/or group traditions (44, 45).
It is also worth mentioning that besides its dietary importance, marrow also has many other artisanal uses. For instance, the Nunamiut use the marrow of ungulates’ distal members to waterproof skins and treat bowstrings (1). It can also be used as fuel for lighting (46) and can even be used in the tanning process, as reported by the traditional peoples of Siberia (47). Whether it was consumed or used for other purposes, the important point here is the capacity to plan and forecast that arises from this fact. The deliberate accumulation of metapodials implies an anticipated concern for future needs and a capacity for “temporal displacement” that surpasses the “here and now” as a means of subsistence (34). Therefore, the study of the preservation or delayed consumption of resources, as well as possible storage systems, has great potential for detecting not only economical but also social and cognitive changes among Middle Pleistocene populations.
Science Advances 09 Oct 2019:
Vol. 5, no. 10, eaav9822
Taking into account the scarcity of postdepositional taphonomic damage and the low influence of mineral density-mediated attrition processes at Qesem, the hominid transport decisions and the ravaging by carnivores were considered as candidates in the search for the main factors to explain the bias of the anatomical profile [e.g., (15, 16)]. Destruction and subsequent ravaging are closely linked to the mineral density of the bones and their portions in the case of carnivores [e.g., (17, 18)]. For example, Madrigal and Holt (19) argued that if the limb bones are processed, the isolated shafts tend to survive carnivore ravaging, while cancellous bone portions will be removed by ravaging carnivores. The scarcity of the epiphyses of long bones, especially the least dense epiphyseal portions, such as the proximal humerus, distal femur, and proximal tibia at Qesem, could raise the possibility of carnivore attrition. However, an underrepresentation of spongy bone is not necessarily only due to carnivore attrition but may be also the result of other causes, including anthropogenic processing, such as bone grease production, or the use of bone as fuel (20). As argued in several previous works, the impact of carnivores on the faunal assemblages at Qesem is minimal [e.g., (15, 16)]; thus, the inspection of the relationship between the anatomical profile and the economic utility of elements in this case becomes relevant to the assessment of economic transport strategies.
The skeletal representation at Qesem is biased toward the high utility elements, with a predominance of limbs and mandibles compared to skulls and axial bones. The ungulate body part profile correlates positively with the UI bone marrow and UMI, pointing to the importance of marrow in hominin transport decisions. However, some specific differences between weight sizes are worth highlighting, since they precisely relate to the representativeness of the metapodials. The %MAU shows very low proportions for the metapodials of large-sized ungulates (e.g., aurochs and horse) with values between 0 and 9.7%. The trend changes completely in the case of small- and medium-sized species (e.g., fallow deer and red deer) with percentages between 65.4 and 84.6. This composition was already detected in the faunal assemblage of the central hearth area and interpreted on the basis of ethnographic parallels once postdepositional processes and carnivore ravaging were ruled out (16). According to some modern ethnographic descriptions, the pattern of disarticulation is highly variable among different hunter-gatherer groups and species. Domínguez-Rodrigo (21) documented an example of variation in the pattern of dismembering in the case of the Maasai people, which differs from the one observed by Gifford-Gonzalez (22). The ethnic group from Peninj (Tanzania) usually severs metapodials from the limbs after the first step of skinning; however, the Massai from the south-east of Kenya remove complete limbs first (without disarticulating them) after evisceration. Among the Hadza or the San, it is repeatedly observed that the preparation of carcasses for transport may involve the consumption of some viscera and marrow from long bones, especially in large ungulates (21, 23). These episodes would lead to the breaking of some marrow-rich bones, such as the metapodials, at the kill site or hunting stations for marrow extracting and immediate consumption. This internal resource would provide an extra nutritional supplement for hunters while they process the carcass and prepare it for transport (7, 24). Marrow extraction is a low-cost activity relative to fat removal in that it only requires a few minutes to completely process a bone, particularly if the bone is not covered by flesh, as is the case of metapodials (17). This phenomenon could explain why the metapodials of large-sized ungulates at Qesem were scarce compared to the quantity of the rest of the limb bones. That is, the initial consumption has been able to condition the variety of bones that were transported to the base camp. A carcass can be conceptualized as a patch of skeletal elements, each with a pursuit and handling cost (25). Nevertheless, we must take into account that other variables could also affect transport decisions and generate different body part profiles, e.g., the distance from the hunting area to the home base, the number of animals harvested simultaneously, the number of participants in the hunting party, the location and time of day when the animals are acquired (e.g., 26, 27), the technological state of development (28), the condition of the animals (7), and the risk of predation by other carnivores (29). The dynamics of carcass transport are complex, and although the degree of difficulty is evident and can vary with each carcass or situational event, major trends can emerge.
O’Connell et al. (30) documented that the abandonment or processing of some limb bones at kill sites is often contingent on prey size. The metapodials of small- and medium-sized ungulates are well represented in both the Amudian and Yabrudian of Qesem Cave contexts, and they correlate with the other limb bones, showing relatively similar quantities. Thus, there seems to be a differential treatment according to weight size as a general trend in Qesem, where small- and medium-sized animals are mainly transported as field-butchered units to base camp. The presence of transverse cut marks on the basipodia and proximal epiphyses/metaphyses of the metapodials suggests that they were almost systematically separated from the intermediate appendicular bones (radius-ulna and tibia). This butchery pattern seems similar to that performed with the metapodials of large-sized ungulates at the kill sites, but now it was performed at the cave after the limb bones were transported whole. However, how can we know if skinning and bone breakage (and the subsequent marrow consumption) were immediate or delayed?
The metapodials of medium- and small-sized animals show the typical signs of intentional percussion to access the marrow, and therefore, a priori, we could consider immediate consumption of the marrow as a snack or additional nutrient during processing or as one of the final stages of the sequence after the extraction of the animal’s external resources. However, our experimental series do not show any differences in the morphology or location of the notches during the first 2 weeks of exposure that would enable us to identify whether the consumption was immediate or slightly delayed. The notable difference takes place from the third week onward, when the notches are less well defined and are replaced by percussion pits associated with cortical flaking and longitudinal or slightly curved fractures. Given the high level of bone fragmentation in the Qesem assemblages, and because of anthropogenic and postdepositional processes (different types of pressure loading, such as trampling and/or soil compaction), metapodial fragments do not always register the impact points (notches or pits), and therefore, our attention must turn back to the fracture planes looking for clues to the condition of the bones at the time they were broken for marrow extraction.
By applying the criteria of Villa and Mahieu (31), the metapodials in Qesem appear to mainly register characteristics of a fresh fracture, with a preference to oblique angles, longitudinal delineations, and smooth surfaces. However, these bones can remain fresh over time, as they maintain not only their collagen in high proportions but also their nutritional values, such as fat and protein (32). In relation to this, the analysis of the fractures in the experimental series revealed that the angles, outlines, and surfaces were similar to those generated by fresh breakage even in weeks 6 to 9 in natural outdoor conditions (scenarios 1 and 2). At this point, we needed to explore more variables.
Obviously, before the metapodials were fractured, they had to be skinned. The cut marks could provide us with data on the state of the skin when it was removed, since the effort to remove this tissue varies depending on whether it is fresh or dry, a circumstance that would also result in a different taphonomic signature. The same situation can be observed when the dried flesh is removed from the bone because the cut marks’ frequency and morphology can vary depending on factors such as the state and weight of attached flesh at the time butchery is undertaken [e.g., (33)]. Dry flesh is more attached to the bone, which is why more effort is required to remove it than when it is fresh, as is the case when the tool reaches the muscular insertions or tendons firmly attached to the bone. This leads not only to a greater number of marks but also to a different pattern with different morphologies and orientations from those observed in the defleshing of large, fresh muscle bundles or when the butchery is performed with a specific purpose, such as extracting long cuts or slices of flesh of roughly standardized shape (i.e., fillets) for drying [e.g., (34)].
Longitudinal and oblique incisions on the lateral sides of the metapodials similar to those that would occur when the skin is in a fresh state have been identified in Qesem. These marks were also occasionally observed in the experimental series, although they were only recorded in the first week of exposure. From the second week, the short (shallow and deep) incisions and sawing marks were predominant, with special relevance on the anterior and posterior surfaces (where the tendons are found), and it is from the fourth week onward that the number of these marks increased along with a variation in the inclination of the sections toward an almost flat oblique position. These types of marks are precisely the ones that predominate in Qesem (77.9% of the anterior/posterior surfaces of metapodial shafts showing cut marks), which would lead us to consider a possible delayed secondary skinning (by at least 2 weeks according to our experiments). Nevertheless, despite the similarity to the experimental marks, we cannot rule out equifinality, i.e., other processes could produce similar cut marks. For instance, we cannot rule out the existence of cultural patterns in processing techniques that give rise to marks with these characteristics. These specific “ways of doing” could be perpetuated over time and materialize in the archaeological record in patterns or in what Yellen (26) called “style” in the butchery among the!Kung Bushmen. However, other types of marks that could be diagnosed with possible secondary processing exist. These are the cortical scars associated with chop marks (or chipped marks), which are sometimes combined with prominent incisions and sawing marks on the anterior/posterior side, showing the same orientation and inclination almost parallel to the bone. These marks were also sporadically generated at the experimental level from the second week and systematically from the seventh week in scenario 1. This atypical damage was caused by the difficulty of removing the dry skin and tendons that remained strongly attached to the bone after outdoor exposure. The presence of these alterations does seem to suggest that some Qesem metapodials could have been processed subsequently (after 2 to 7 weeks), and it also makes the previous type of marks more relevant for this interpretation.
According to the nutritional analyses of the experimental sample, the marrow of the metapodials was conserved in good condition in the outdoor autumn scenario (scenario 1), preserving useful nutrients until the ninth week; however, in the indoor and outdoor spring series (scenarios 2 and 3), the marrow showed a significant decrease week by week, which was particularly noticeable from the third week. Thus, seasonality seems to be an important variable when assessing marrow degradation. This fact is interesting because in Qesem Cave, seasonal hunting peaks have been detected that specifically include late summer through autumn, during and/or after the rutting time (16, 35).
From a microbiological perspective, the delayed consumption of marrow also seems to be relatively safer than consuming dry meat, since the marrow remains encapsulated by the bone, offering protection against microbes, even when the bacteria have been injected into the circulatory system and have reached the marrow via the nutrient artery (9). The study by Smith et al. (9) showed that, in raw meat, all bacterial populations grew rapidly within 24 hours; in contrast, the number of colony-forming units in samples taken from marrow inside the bone was consistently low.
Apart from bone coverage, the skin could also provide insulation or have a protective effect against insects and/or bacteria. Insects play an important role in carcass decomposition processes. By transporting microbes and producing young that tunnel and aerate the tissues of the carcasses, insects alter the microbial and physical nature of the carrion in such a way that they promote bacterial growth (36). In the case of the metapodials, the skin and tendons are in direct contact with the bone, and in the absence of soft tissues (such as flesh) susceptible to being rapidly colonized by bacteria, they could offer preservation advantages in the case of outdoor exposure. Although this hypothesis seems logical, the truth is that in the experimental level, the metapodials exposed without skin in scenario 3 did not show statistically significant differences in nutritional degradation compared to those exposed with skin. Despite this, during the preparation of samples for chemical analysis, a different aspect was detected in the marrow that came from the skinless metapodials, which had a more gelatinous, harder, and pinker appearance. In any case, Qesem’s metapodials register marks that indicate that they were accumulated with skin to be processed secondarily and later in time in an attempt to preserve the bone marrow.
Accumulating bones for delayed consumption of grease and marrow has been documented ethnographically among Nunamiut Eskimo communities, where the bones are stored during the winter months to be processed in large batches (1). The Loucheux people also process the bones secondarily and with a slight delay, although normally they do not exceed 3 days of outdoor exposure; once the grease/fat is extracted, these groups store it inside the stomach of caribou (converted into bags), where they claim that it stays in good condition for 2 or 3 years (24). Another example of the use of ungulate organs to store bone grease after rendering comes from the Comanche and Blackfoot people, who store dried meat mixed with bone grease and marrow in stomachs, intestines, and rawhide bags sealed airtight with tallow [e.g., (37)].
Ethnographic studies have shown that a significant number of nonagrarian peoples engage in some sort of delayed consumption [e.g., (38)]. This practice often requires the development of preservation techniques (mainly in the case of meat), which can vary depending on factors such as geographical area, environmental conditions, seasonality, and/or technological capabilities [e.g., (39–41)]. Drying meat under natural temperatures, humidity, and air circulation, including direct sunlight, is perhaps one of the simplest methods. This presumably applies to smoking too, as it also involves the removal of moisture from the meat (40). Smoking meat has an added preservative effect, apart from surface drying, in that the smoke from the sawdust contains bactericidal agents, such as formaldehyde, and also inhibits fat oxidation (41). During colder seasons in northern environments, freezing is another method that would allow preservation of internal and external resources (i.e., meat and fat/grease) without much effort, permitting entire articulated carcasses (or with minimal field butchery) to be cached after skinning and gutting (39).
Hunter-gatherer food storage is considered a “risk-reducing mechanism” designed to offset seasonal downturns in resource availability and is typically seen as evidence of intensified subsistence activities [e.g., (42)]. Recently, Speth (43) argued the potential use of fermented and deliberately rotted meat and fish in forager diets throughout the arctic and subarctic, concluding that putrefied food was widely used as a desirable and nutritionally important component of human diets (and not solely as starvation food). Fermentation is a widespread technique used for food preparation and preservation. These types of “processed” foods can also have dietary benefits and are even considered delicious (instead of unpleasant) by people who grow up eating them (44). Speth (43) extended this approach to the Eurasian Middle Palaeolithic hominids who inhabited analogous environments, suggesting the possibility of delayed consumption among the Middle and early Late Pleistocene populations. At this point, it can be assumed that bone marrow could also have been part of this pack of resources susceptible to being processed secondarily over time. Marrow FA composition evolves with time of conservation, showing a decrease of monounsaturated FAs presumably due to its oxidation into shorter chain products, including dicarboxylic acids and short-chain FAs. These products could make fats taste and smell rancid. It is difficult to know if this rancidity could have impaired the consumption of aged marrow, but, as in the case of dry meat, we could assume that the preference for this type of aging depends on the consumer and/or group traditions (44, 45).
It is also worth mentioning that besides its dietary importance, marrow also has many other artisanal uses. For instance, the Nunamiut use the marrow of ungulates’ distal members to waterproof skins and treat bowstrings (1). It can also be used as fuel for lighting (46) and can even be used in the tanning process, as reported by the traditional peoples of Siberia (47). Whether it was consumed or used for other purposes, the important point here is the capacity to plan and forecast that arises from this fact. The deliberate accumulation of metapodials implies an anticipated concern for future needs and a capacity for “temporal displacement” that surpasses the “here and now” as a means of subsistence (34). Therefore, the study of the preservation or delayed consumption of resources, as well as possible storage systems, has great potential for detecting not only economical but also social and cognitive changes among Middle Pleistocene populations.
Science Advances 09 Oct 2019:
Vol. 5, no. 10, eaav9822