The first hominid meat eaters?

Based of dental morphologies, it has long been believed that Australopithecus africanus subsisted on a diet of fruits and leaves—not unlike that of a chimpanzee. However, stable carbon isotope analysis by Matt Sponheimer and Julia Lee-Thorp show a different dietary story for these early hominids.

Stable isotope analysis of molar tooth enamel from A. africanus specimen from Makapansgat, South Africa show that, despite being well adapted for tree foraging, a large part of their diet consisted of carbon 13-rich foods that are found in open grasslands. This would include grasses and sedges, or possibly the animals that consumed these foods these food-sources. It is commonly believed that stone-tool wielding; large brained Homo species were the first to consume meat. But, this stable carbon isotope analysis may generate a new idea in regards to who the first meat-eating member of the hominid line really was.

To get a better idea of the ecological context of the Makapansgat africanus, Sponheimer and Lee-Thorp also analyzed the enamel of other fossil fauna in the area. The stable isotope results from A. africanus differed from the grazers and browsers of the area, while they shared similarities the carnivore Hyaena makapani. The analysis showed that all but one specimen fell outside the range that corresponds to diets that relied heavily on the consumption of fruit and leaves.

These results could suggest that A. africanus may have utilized grasses and sedges to avoid competition. However, the tooth wear patterns of A. africanus are not consistent with grass eaters. It is also possible that they were consuming plant-eating insects of young grazing mammals. To further the argument, the stable isotope analysis from early Homo specimen did not show any more indication for meat consumption then africanus, They propose, “The primary dietary difference between A. africanus and Homo may not have been the quality of their food but their manner of procuring it.”

Extent chimpanzees could be a clue to the dietary patterns of A. africanus. They occasionally supplement their diet with meat, and are known for eating C-13 rich insects. It seems likely that the dentally similar A. africanus would do the same thing.

The evidence given by Sponheimer and Lee-Thorp is not completely conclusive. It is possible that A. africanus was subsisting in grasses or on animals that consumed those grasses. However, it is compelling evidence that suggests that Homo may not have been the first meat eater. Regardless of what exactly A. africanus was eating, it does give interesting insight into their subsistence strategies. Whether they were eating grasses and sedges, termites, hunting mammals, or scavenging, this evidence shows that early hominids were broadening their resource base.

Sponheimer Matt and Julia Lee-Thorp. 1999. "Isotopic Evidence for the Diet of an Early Hominid, Australopithecus Africanus." Science 283, no. 5400: 368-70.

Late Pleistocene Prey Choice

It is often debated whether large game such as mammoth would have been an optimum resource for the Late Pleistocene hunter-gatherers of North America. While a mammoth would have provided an exuberant amount of energy in terms of caloric quality, the post-encounter handling cost that comes with frequent mammoth predation would have been quite high. Tracking, bringing down, butchering, and then transporting a mammoth, must have been an incredibly costly endeavored. It is possible that, after the extreme handling cost, the energy return of hunting mammoth may have been less then that of medium size pray like ungulates. Including a wide range of fauna into a diet may have been more desirable subsistence method.

David Byers evaluates this issue by comparing the caloric yield and handling cost of mammoths to African elephants. Using the elephant analog and by creating an estimating encounter rates (based off of body size in relation to prey density), Byers formulates an optimal diet curve for Late Pleistocene hunter. Diet breadth is predicted by analyzing the caloric value based off elephant weight and usable meat. This is coupled with an analysis of handling time and return rates.

It is concluded that the acquisition of megafauna such as mammoth would have been “profitable within a very narrow range of circumstances where such prey were extremely abundant, easily procured, and could be processed at minimal time cost.” It would have been more likely that a wide range of mammals, both large and mid-sized, were utilized. Large, high-ranking game was probably taken when possible, but it was probably never abundant enough to allow for the proposed narrow hunting specialization.

Byers’ empirical method of analyzing Late Pleistocene prey-choice is very intriguing. It puts quantitative data behind ideas that are often only speculated. However, there seems to be an unavoidable potential for error when trying to recreate such non-analog environments and groups of people.

The study emphasizes the importance of encounter rates when discussing diet breadth. Although the body size of an animal may play a large role in prey density, many more environmental factors are involved. It would be reasonable to assume that environmental factors may have resulted in different prey-density in different areas. It is likely that some Late Pleistocene hunters had a larger diet-breadth then others. Also, the handling costs that were estimated through modern ethnographic comparison may be drastically different from that of Pleistocene hunter-gatherers.

In addition, there are many factors that go into diet choice, such as the social stigma of a particular food choice and taste that are impossible to account for when recreating diets of the distant past. If resources were abundant enough, the people of the Late Pleistocene may have had cultural influences that played a role in their diet choice.

Despite the unavoidable problems that come with implementing modern analog, the conclusion that North American Late Pleistocene relied on a wide range of resources is a reasonable one. It seems unlikely that they would focus on only large game—especially when handling cost are so high. Mammoths and other large game may have been a very desirable food source, but that does not negate the fact that other protein sources were probably more abundant and came with lower post-encounter handling costs.

Byers, David A. 2005 “Should we expect large game specialization in the late Pleistocene? An optimal foraging perspective on early Paleoindian prey choice.” Journal of Archaeological Science. 32:1624-1640

Evolutionary History of Hunter-Gatherer Marriage Practices

Robert Walker’s article starts out “Marriage is a human universal that unites males and females in socially recognized reproductive units.” Marriage goes beyond reproductive significance as a principle form of economic, social and kinship ties. By framing marriage in this manner he hopes to figure out if reciprocal marriage is the original form of marriage, or whether it is a more recent phenomenon

In a comparative study of 190 hunter-gatherer socities, 85% had arranged marriages. 80% of the total sample employed a bride price, and less than 17% of marriages are polygynous. The common forms of marriage across hunter-gatherer cultures suggests an underlying structure for marriage.

Combining mitochondrial genetics and phylogenic reconstructions show interesting relationships about the evolution of marriage. There are low levels of polygyny in early humans, with the exception of Australian aborigines. The practice of brideprice seems to be a common state for all early humans. Determining the role of courtship versus arranged marriages is more difficult to determine. Three of four African hunter-gatherer groups employ courtship rituals, making ancestral determination a mix of both.

Statistical associations between types of marriages indicate that polygyny is more likely to occur in larger families when the kin, and not the parents, arrange the marriages. When hunter-gatherers with arranged marriages are related the ecological variables used by Binford to construct his hunter gatherer database, no associations can be seen. It more likely that marriage traits change slowly through time, and only rapidly change when pressure is put on by outside cultures.

There are a few problems with the methods employed by Walker in this article. He created a basic phylogeny structure by using studies that have tracked mitochondrial DNA to create branches from a common African ancestor. These mitochondrial studies have suffered from many inaccuracies and different studies will create different human population offshoots.

On to this phylogenic tree he overlays known marriage practices of hunter-gatherer groups onto the ends of the branches. Then treating arranged and courtship marriages like genetic traits, he plots back cultural inheritance back to a common African ancestral group, despite the fact that cultural transmission does not follow genetic pathways. This leads him to have to put in “equivocal” nodes when it leads to both courtship and arranged marriages.

It seems like he puts in an obligatory section on how modern hunter-gatherers are not simple relics from the Pleistocene to cover how modern hunter-gatherers don’t create a straight phylogeny. But in the next sentence he disempowers hunter-gatherers by stating how marginal habitats, pressure from agricultural neighbors, and acculturation have all affected HG life-ways to destabilize their marriage practices. In sum, the concept of tracing marriage practices through time is novel, but the methods employed leave a lot to be desired. I remain skeptical about the conclusions of this article until further methodology and analysis can confirm.

Walker RS, Hill KR, Flinn MV, Ellsworth RM (2011) Evolutionary History of Hunter-Gatherer Marriage Practices. PLoS ONE 6(4): e19066

Oral Traditions as Survival Strategies

The lifeways of hunter-gatherer groups may be considered to be precarious.  These highly mobile groups of foragers and hunters lived close to the earth and resource scarcity was often a recurring theme in their lives.  In response to scarcity, these groups needed the ability to deal with short and long-term recource fluctuations.

Foraging and hunting has been the economic pattern of hominids (modern humans and their bipedal ancestros) for almost three million years until the Neolithic Revolution which began the domestication of plants and animals, shifting groups economies to a more sedentary and agricultural lifestyle.  Over this span of several million years these hunting and foraging groups must have developed and maintained strategies that allowed their sociocultural systems to survive cycles of resource scarcity (Minc  1986:40) both short and long term.

During times of scarcity, behaviors and alternatives that had maintained group survival and reproduction in the past would result in the formation of adaptive knowledge that would provide a survival strategy.  This knowledge or information would be maintained within societies because it would be a, "prerequisite to decision making at a given moment in time" (Minc 1986:41).  This information, crucial to the survival and reproduction of the group would be retained in some form that could be culturally conveyed through time (Minc 1986:41).

One way this transmission occurs is through the oral tradition of the society.  Michell Sugiyama (2001) speaks to the universality of themes within folklore worldwide.  This universality would indicate that folklore is an adaptive means of treating adaptive problems.  It is Sugiyama's contention that this universality, "lends support to the hypothesis that storytelling originally emerged as a means of storing and transmitting certain types of fitness-related inforomation" (Sugiyama 2001:242).  Amyth, according to Sugiyama, may seem an impossible tale with talking animals and imaginary beings yet they contain accuracy in their descriptions of geography and plants as well as knowledge of where animals are located and how to kill and process them (Sugiyama 2001:239).

The universality of folklore is mainly at the "macro" level, dealing with issues common to all cultures such as survival and reproduction.  Variation would occur at the "micro" level where individual cultures deal with adaptive problems unique to their particular habitation areas or lifeways (Sugiyama 2001:243).

The environment is a major factor in the structuring and organizing of societies.  Intimate knowledge of the environment that continued social reproduction would be important to maintain and transmit.  Oral traditions are references to what was done in the past.  They are the repositories of past events and their outcomes and are able to provide information in formulating survival strategies to meet current conditions.

I submit oral tradition provides the information necessary in decision-making that results in adaptive survival strategies in how to deal with environmental variability and is one way of surviving resource scarcities.

Minc, Leah D.
    1986 Scarcity and survival: The role of oral tradition in mediating subsistencew crises. Journal of
       Anthropological Archaeology 5:39-113.

Sugiyama, Michelle Scalise
    2001 Narrative theory and function: Why evolution matters. Philosophy and Literature 25(2):233-250.

Core Use-Lives and the Problems That Could Arise When Using Core/Biface Ratios

In the article, “Core/Biface Ratios, Mobility, Refitting, and Artifact Use-Lives,” Douglas Bamforth and Mark Becker take off where Parry and Kelly left off with the use of core/biface ratios. They analyze another group of southwestern Paleo-Indian sites to show that variability within these groups such a great extent that using core/biface ratios alone will not account for. They restate what Parry and Kelly found, which shows that mobile hunter-gatherers typically have more bifaces while sedentary groups have more cores. Therefore, low core/biface ratios illustrate a highly mobile group, while high core/biface ratios show a more sedentary lifestyle.

They present many arguments against Parry and Kelly’s analysis by showing that assumptions can lead to errors. First, they claim that the assumption that artifacts accurately represent the tool kits used by prehistoric people is very unreliable. Sites with short occupations will leave behind fewer artifacts than groups that stay in one spot. Therefore, highly mobile groups will never leave an accurate portrayal of their tool kit at one site. Also, the use-lives of portable bifaces tend to be longer, leading towards its discard at the site it was used very unlikely. Bamforth and Becker also state that cores tend to pass through sites more often, leading to more instances of expedient reduction sequences.

They also show that there are regional differences between Paleo-Indian sites, even in the southwest Plains area. In their results, they show that higher core/biface ratios occur in the north and east, while lower values occur in the southern and western portions of the western United States. Bamforth and Becker show that this has nothing to do with raw material availability, but rather errors in the method of using cores only. They claim that other production debris should also be considered in the analysis of lithics to determine mobility. This way you can determine the frequencies of retouched pieces in an assemblage.

Bamforth and Becker claim that retouch frequencies are a better proxy for technological change, rather than Parry and Kelly’s core/biface method. When analyzing cores only, it only accounts for changes in sedentism. People can remain in one spot and never change their reduction strategy; however, core/biface ratios will not account for this because of the amounts of lithics that come with staying put in one spot. Therefore, even if this was the case, the core/biface ratios of the cores on site will indicate an expedient reduction regardless of the technological strategy utilized. By analyzing retouched pieces would show an increase in retouched frequencies if a formal strategy is used in a logistical setting. Therefore, retouch frequencies are a better indication of technological change.

Bamforth and Becker show that at the Allen Site in North America, the core/biface ratios show that the site was occupied for a short duration. However, several large bifacial cores as well as knives are available at the site. They also refitted a sequence of lithics which show that higher ratios were calculated then just the recovered artifacts. This shows that including debitage and other production debris is important in the analysis of mobility. Cores will only lead to faulty conclusions since they only represent a small portion of a given assemblage. Bamforth and Becker did an excellent job of pointing out the flaws and errors with the use of cores as a proxy of both technological change and prehistoric land-use strategies. By showing that the variation in Paleo-Indian assemblages can lead to different results when analyzing their lithics, they illustrated the point to never use one sole method to determine prehistoric lifestyles.

Douglas B. Bamforth and Mark S. Becker. Core/biface ratios: Mobility, refitting, and artifact use-lives: A Paleoind. Plains Anthropologist, Aug 2000; 45, 173, 273-290.

The Organization of Core Technology - Cores and Sedentism

William Parry and Robert Kelly offer great insights into core classification with their chapter, “Expedient Core Technology and Sedentism” in the book, The Organization of Core Technology. They begin by explaining how bifacial production leaves patterned traces in the archaeological record. As time passed into the late prehistoric and contact phases, assemblages began to reflect a more expedient core reduction technique. In these contexts, formal cores and retouched elements tend to become rare. They feel this is both a shift in response to a decreased mobility strategy, as well as a major change in technological organization.

They then explain the differences between expedient and formal reduction techniques. Expedient reduction tends to have no secondary retouch, and they are manufactured with a specific task in mind. This differs from formal technology which has a prepared form in mind. Therefore, form selection in groups associated with expedient core technology is not stressed. In this reduction sequence, flakes are struck off randomly from the core which is referred to as bipolar technique. This particularly technique, as Parry and Kelly indicate, requires no previous training or practice whatsoever. It requires little expenditure of time, and very little effort on the knapper’s part. The tools themselves that are flaked from the core are typically only used once and then discarded.

This contrasts with formal techniques, where bifaces are much harder to learn how to manufacture and take a great deal of time to do so. They also are typically used several times for a variety of tasks by retouching the edges to extend its use-life, making their cutting edges much more useful. These cores are typically standardized as well, resulting in a specific tool form. Bifaces also are very portable, allowing highly mobile groups to carry them with ease compared to large cores. This is considered a more efficient use of raw material as well, as expedient reduction is fairly wasteful since the use-lives of tools are typically very short and must be replaced with a new flake.

After describing these types of cores, they show through different groups how mobility can be determined by analyzing this type of lithic technology. The three groups they analyzed were: various North American Paleo-Indian groups (Eastern Woodlands, Plains, and Southwest groups), Mesoamerican cultures (particularly Archaic and Early Formative), and Neolithic European groups. They found that with the Paleo-Indian groups, a change towards expedient core reduction occurred around AD 500 (AD 300 for the Plains, and AD 600 for the Southwest). In some regions, the change was dramatic. In others, it was a long drawn-out process. Regardless of the speed, the shift seemed to correspond with changes in settlement patterns (i.e. – the first large permanent villages). This seemed to be the case with the other groups studied as well. Though very late (1500-1000BC), there is an emphasis on expedient core technology when very large settlements began to sprout in the region. However, the sample is small due to rarity of lithic samples from the area. Also, it has been found that in some areas, such as the Tehuacan Valley, there was an increase in formal tools. Parry and Kelly claim that this is probably a lack of sufficient data or a bias in sampling. And last but not least, the Neolithic period indicates a shift to expedient reduction compared to the Mesolithic preceding it. They claim that this is also indicative of a change in sedentism.

Parry and Kelly offer a great explanation for their results and claims. They show that the changes in core technologies is not related to other technological innovations, local conditions, raw material availability, progress, or even a shift toward agriculture. They found that in all contexts, these scenarios were not applicable. The shift was only in regard to changes in settlement patterns. As people began to become more and more sedentary, they began to change their technology in a way that would best suite their particular lifestyles. Parry and Kelly provide great examples of different groups in different regions that support their arguments.

Parry, W. and R. Kelly. Expedient Core Technology and Sedentism. In: The Organization of Core Technology, edited by J. Johnson and C. Morrow, 285-308. Westview Press, Boulder, Colorado, 1987.

Core Technology in the Levant

Ian Wallace and John Shea’s article, “Mobility Patterns and core technologies in the Middle Paleolithic of the Levant,” discusses the correlation between core types and land use management. They state that expedient core patterns in lithic assemblages are indicative of decreased mobility and a shift towards logistical mobility strategies, or what they refer to as radiating mobility (collectors). This is because most expedient cores indicate little core preparation, as well as little retouch and reuse of tools from these cores. Because formal cores tend to be portable bifaces, curated assemblages indicate a more mobile strategy on the land, or circulating mobility strategies (foragers). These tools tend to be used time and time again for a variety of tasks.

Levantine Middle Paleolithic assemblages typically are dominated by this type of core technique, though cores are typically the least common part of a lithic assemblage. Wallace and Shea believe that the final core forms found at sites are an accurate depiction of core reduction techniques utilized by prehistoric people. However, they do acknowledge that cores are by no means static. A core can start out its use-life as an expedient core reduction strategy and later be used as a biface (formal). This could lead to potential errors when only analyzing cores at a given site. Mobility strategies are also not static, as Wallace and Shea point out. If logistical strategies are less costly than residential for a group of people, then the switch to a different mobility strategy would make sense.

The authors also analyze these cores according to both temporal and spatial scales. They analyze the sites according to their location on the map (i.e. – interior, coastal, and ecotone), and try to see if any differences exist according to the site’s location in the Levant. They also include an analysis of different phases within the Middle Paleolithic. They call these early, middle and late Middle Paleolithic, and they seem to correspond with changes in temperatures and climate. What they conclude is that there is a general increase in the emphasis on expedient core strategies. The coastal sites show more expedient cores, while the interior had fewer expedient cores. The ecotone region, or the intermediate region between the interior and coast, had fewer formal cores, but more cores-on-flakes.

But this could reflect Wallace and Shea’s potential errors with their core classifications. They have two categories which do not fit their formal/expedient classes: others and cores-on-flakes. They claim that cores-on-flakes could be either a formal or expedient reduction strategy because it does not reflect either exclusively. However, the amount of cores-on-flakes at each site is rather large compared to the other two core values. If they were incorporated into either expedient or formal, then we might see some major differences in results. They also leave out a good deal of layers and sites in the region, which must be included for a complete view of prehistoric life in the Levant.

Regardless of some of these issues, Wallace and Shea provide a thorough lithic analysis of the Levant and several of its sites. They show that easy calculations can lead to some insightful trends between given assemblages. They also provide a unique analysis of the differences in Levant regions, and the changes it has experienced over time, and at the same time, indicating these changes and different zones played an important role in land-use strategies in prehistory. They also seem to address most of the potential errors in their work, which is always a positive when using only one method to determine lifestyles far into the past. This will always be problematic unless correlated to other forms of evidence to support it.

Wallace, I.J., and Shea, John J., 2006. Mobility patterns and core technologies in the Middle Paleolithic of the Levant. Journal of Archaeological Science 33, 1293–1309.