Lidar survey 'compels' revaluation of aspects of ancient Maya society

An airborne laser mapping survey of over 2,000 square kilometers of northern Guatemala - the largest such survey to date of this region - "compels" a revaluation of Maya demography, agriculture, and political economy, according to its authors.

The lidar survey data, which identified over 61,000 ancient structures hidden amidst the dense tropical forests of the region, was further analyzed by multi-national, interdisciplinary teams, whose interpretations of urban and rural density and transportation networks, among other facets, suggest that future field work should involve a reevaluation of settlement and land use of the Classic lowland Maya.

Lidar, a technology that uses pulses of laser light to map land cover and topography in 3-D, has allowed archaeologists to study ancient Maya society on a regional scale. Due to the heavily forested areas throughout much of the central Maya Lowlands, discovering new sites is difficult - fully mapping and characterizing a single settlement can take many years. As such, data concerning ancient Maya urbanism, population, land use and socio-political complexity has been limited.

Aerial lidar survey, however, can map large areas of the ground surface below the forest canopy quickly and in detail, recording ancient structures, roadways or agricultural features at a landscape scale. Here, Marcello Canuto and colleagues present the results of what they call the largest lidar survey to date of the lowland Maya region. Canuto et al. mapped 12 separate areas in Petén, Guatemala, to characterize Maya settlement, from cities to hinterland, across varied regions of the Maya Lowlands.

Using the data, authors estimate upwards of 11 million people lived throughout the Maya Lowlands during the Late Classic Period (650 - 800 CE), numbers in agreement with previous estimates. But populations of such scale would have required some degree of agricultural intensification - the extent of which has previously been unknown for the region - to sustain them, say the authors.

Their work now demonstrates that a great deal of the wetlands throughout the region were heavily modified for agricultural use. What's more, networks of roadways connected distant cities and towns - some of which were heavily fortified, an unexpected finding according to the authors. In a related Perspective, Anabel Ford and Sherman Horn caution against relying solely on lidar data and suggest it should not replace traditional "boots on the ground" archaeological survey methods.

Violence in pre-Columbian Panama

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One of two cases of healed blows to the cranium from the Playa Venado excavations. Most of the evidence of violence was interpreted by Harvard archaeologist, Samuel Lothrop based on body positioning in graves at the site. Smithsonian post-doctoral fellow, Nicole Smith-Guzmán, found no examples of trauma that occurred near the time of death among the skeletons in the collection.

Credit: Nicole Smith-Guzmán, STRI

Buried alive. Butchered. Decapitated. Hacked. Mutilated. Killed. Archaeologist Samuel K. Lothrop did not obfuscate when describing what he thought had happened to the 220 bodies his expedition excavated from Panama's Playa Venado site in 1951. The only problem is that Lothrop likely got it wrong. A new evaluation of the site's remains by Smithsonian archaeologists revealed no signs of trauma at or near time of death. The burial site likely tells a more culturally nuanced story.

 

The "long-overdue" reexamination of the Playa Venado site, which dates to 500-900 A.D. and is located near the Pacific entrance to the Panama Canal, revealed no evidence of ritual killing, said Nicole E. Smith-Guzmán, post-doctoral fellow at the Smithsonian Tropical Research Institute (STRI). Lothrop's misinterpretations are likely due to the era of "Romantic archaeology," underdeveloped methods for mortuary studies and literal readings of Spanish accounts of indigenous peoples after European contact.

"We now realize that many of these Spanish chroniclers were motivated to show the indigenous populations they encountered as 'uncivilized' and in need of conquering," said Smith-Guzmán, adding that many accounts of sacrifice and cannibalism have not been confirmed by the archaeological record. "Rather than an example of violent death and careless deposition, Playa Venado presents an example of how pre-Columbian societies in the Isthmo-Colombian area showed respect and care for their kin after death."

The article, co-authored by STRI staff archaeologist Richard Cooke, was published in Latin American Antiquity. But Lothrop's 1954 paper, "Suicide, sacrifice and mutilations in burials at Venado Beach, Panama," left its mark on the annals of Panamanian archaeology. It has been cited more than 35 times as evidence of violence, cannibalism or trophy decapitation. Some authors have used the paper to suggest Playa Venado is a mass burial site or a manifestation of conflict.
In defense of Lothrop, who was an archaeologist with Harvard University's Peabody Museum of Archaeology and Enthnology, bioarchaeology (the study of human remains from archaeological contexts) did not exist as a sub-discipline until two decades after his work concluded at Playa Venado. Today's practitioners also benefit from methods developed in the 1980s and 1990s.
Lothrop's careful documentation and preservation of remains made reevaluation possible. Remains from more than 70 individuals from Playa Venado are at the Smithsonian's National Museum of Natural History, sent there by Lothrop for osteological evaluation.
Upon examination, Smith-Guzmán found only wounds that showed signs of healing well before the individuals died, including blows to the head and a dislocated thumb. Various broken bones and disarticulated remains discovered by Lothrop more likely explained by normal processes of decomposition and secondary burial of remains, which is believed to have a common ancestor-veneration practice in pre-Colombian Panama.
Evidence suggests certain people's remains were preserved for long periods of time before being buried in ritual contexts. "At Playa Venado, we see a lot of evidence of adults being buried next to urns containing children, multiple burials including one primary and one secondary burial, and disturbance of previously laid graves in order to inter another individual in association," said Smith-Guzmán.
"The uniform burial positioning and the absence of perimortem (around the time of death) trauma stands in contradiction to Lothrop's interpretation of violent death at the site," said Smith-Guzmán, who also used evidence from other archaeological sites around Panama about burial rites as part of the investigation. "There are low rates of trauma in general, and the open mouths of skeletons Lothrop noted are more easily explained by normal muscle relaxation after death and decay."
Smith-Guzmán and Cooke's reassessment of the Playa Venado burials suggests that ideas about widespread violence in pre-Columbian Panama need to be reconsidered. The research is part of a larger, interdisciplinary site reanalysis that will be published by the Dumbarton Oaks Museum in Washington, D.C..

South East Asian population boom 4,000 years ago

Researchers at The Australian National University (ANU) have uncovered a previously unconfirmed population boom across South East Asia that occurred 4,000 years ago, thanks to a new method for measuring prehistoric population growth.

Using the new population measurement method, which utilises human skeletal remains, they have been able to prove a significant rapid increase in growth across populations in Thailand, China and Vietnam during the Neolithic Period, and a second subsequent rise in the Iron Age.

Lead researcher Clare McFadden, a PhD Scholar with the ANU School of Archaeology and Anthropology, said the population trend was consistent across samples taken from 15 locations.

"We saw huge population growth associated with the agricultural transition," McFadden said.

"Up until about 4,000 years ago you have hunter gatherer type populations, then you have the introduction and intensification of agriculture.

"Agricultural transition has been widely studied around the world and we consistently see significant population growth as a result."

The reason these population changes have never been quantified before is the tools used to measure prehistoric populations were all designed for Europe and the Americas where archaeological conditions are different to Asia.

Ms McFadden said the difference comes down to how children are represented in population numbers.

"For skeletal remains in Europe and America we often see the complete absence of infants and children, they are very poorly represented," she said.

"The preservation isn't good - small bones don't preserve well. Children are also thought to often be buried in a different cemetery to adults.

"So the method researchers used to measure populations excluded children because they didn't have accurate representation."

Ms McFadden said her new method for determining the rate of natural population increase takes into account the proportion of infants and children compared to the total population. This way researchers were able to bring population growth figures in line with other archaeological evidence in the region which suggested a rapid rise.

"In South East Asia and the Pacific, we actually have pretty good preservation of bones from children," she said.

"The skeletal evidence was there, we were seeing populations with huge numbers of infants and children compared to the adult populations, which suggests it was a growing population at that time. But the existing tools weren't detecting that growth.

"The trends the new tool found aligned perfectly with what researchers expect to see in response to agriculture."

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The study has been published in a paper in the Journal of Archaeological Science.

Wild animals were routinely captured and traded in ancient Mesoamerica

New evidence from the Maya city of Copan, in Honduras, reveals that ancient Mesoamericans routinely captured and traded wild animals for symbolic and ritual purposes, according to a study published September 12, 2018 in the open-access journal PLOS ONE by Nawa Sugiyama from George Mason University, Virginia, USA, and colleagues: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0202958.

Ancient Mesoamerican cultures used wild animals such as puma and jaguar for many purposes, including in symbolic displays of status and power, as subjects of ritual sacrifice, and as resources for processing into venison or craft products. Evidence of wild animal use in ancient Mesoamerica dates back to the Teotihuacan culture in what is now central Mexico (A.D. 1-550).

Archaeological findings of indigenous Mesoamerican animal management strategies have traditionally been underemphasized, due to the paucity of large domesticated game in the New World in comparison to the devastating impact of European livestock introduced in the 1500s. In this study, the research team analyzed archaeological samples of wild animals excavated from five ritual sites in the Maya city of Copan (A.D. 426-822), in Honduras.

The team performed stable isotope analyses on bone and teeth from puma, jaguar and other unidentified felids along with deer, owl, spoonbill, and crocodile, to determine the diet and geographical origin of the animals. Some of the felid specimens tested, including puma and jaguar, had high levels of C4 intake indicative of an anthropogenic diet despite the absence of indicators of captive breeding. Oxygen isotope levels in deer and felid specimens suggest that some animals and derived craft products (e.g. pelts) used in ritual practices originated in distant regions of the Copan Valley.

These findings confirm previous research showing that Mesoamerican cultures kept wild animals in captivity for ritual purposes and reveal that animal trade networks across ancient Mesoamerica were more extensive than previously thought.

Sugiyama summarizes: "Encoded into the bones of jaguars and pumas at the Maya site of Copan was evidence of both captivity and of expansive trade networks trading ritualized carnivores across the dynamic Mesoamerican landscape."

Multimedia graphic design -- 73,000 years ago

Drawing on a piece of silcrete found in Blombos Cave in South Africa predates previous human-made drawings by at least 30,000 years

The earliest evidence of a drawing made by humans has been found in Blombos Cave in the southern Cape in South Africa.

The drawing, which consists of three red lines cross-hatched with six separate lines, was intentionally drawn on a smooth silcrete flake about 73 000 years ago. This predates previous drawing from Africa, Europe and Southeast Asia by at least 30 000 years.

The drawing on the silcrete flake was a surprising find by archaeologist Dr Luca Pollarolo, an honorary research fellow at the University of the Witwatersrand (Wits), while he painstakingly sifted through thousands of similar flakes that were excavated from Blombos Cave at the Wits University satellite laboratory in Cape Town.

Blombos Cave has been excavated by Professor Christopher Henshilwood and Dr Karen van Niekerk since 1991. It contains material dating from 100 000 - 70 000 years ago, a time period referred to as the Middle Stone Age, as well as younger, Later Stone Age material dating from 2000 - 300 years ago.

Henshilwood holds a Research Chair at the University of Witwatersrand in South Africa, and is the Director of a newly granted Centre of Excellence at the University of Bergen, Centre for Early Sapiens Behaviour (SapienCE). Van Niekerk is a Principal Investigator at SapienCE. The team's findings on the 73 000-year-old drawing was published in the high impact journal, Nature, on 12 September.

Realising that the lines on the flake were unlike anything that the team had come across from the cave before, they set out to answer the questions it posed. Were these lines natural, or a part of the matrix of the rock? Were they, perhaps, made by humans living in Blombos Cave 73 000 years ago? If humans made the lines, how did they make them, and why?

Under the guidance of Professor Francesco d'Errico at the PACEA lab of the University of Bordeaux, France (the second author of the paper) the team examined and photographed the piece under a microscope to establish whether the lines were part of the stone or whether it was applied to it. To ensure their results, they also examined the piece by using RAMAN spectroscopy and an electron microscope. After confirming the lines were applied to the stone, the team experimented with various paint and drawing techniques and found that the drawings were made with an ochre crayon, with a tip of between 1 and 3 millimetres thick. Further, the abrupt termination of the lines at the edge of the flake also suggested that the pattern originally extended over a larger surface, and may have been more complex in its entirety.

"Before this discovery, Palaeolithic archaeologists have for a long time been convinced that unambiguous symbols first appeared when Homo sapiens entered Europe, about 40 000 years ago, and later replaced local Neanderthals," says Henshilwood. "Recent archaeological discoveries in Africa, Europe and Asia, in which members of our team have often participated, support a much earlier emergence for the production and use of symbols."

The earliest known engraving, a zig-zag pattern, incised on a fresh water shell from Trinil, Java, was found in layers dated to 540 000 years ago and a recent article has proposed that painted representations in three caves of the Iberian Peninsula were 64,000 years old and therefore produced by Neanderthals. This makes the drawing on the Blombos silcrete flake the oldest drawing by Homo sapiens ever found.

Although abstract and figurative representations are generally considered conclusive indicators of the use of symbols, assessing the symbolic dimension of the earliest possible graphisms is tricky.
Symbols are an inherent part of our humanity. They can be inscribed on our bodies in the form of tattoos and scarifications or cover them through the application of particular clothing, ornaments and the way we dress our hair.

Language, writing, mathematics, religion, laws could not possibly exist without the typically human capacity to master the creation and transmission of symbols and our ability to embody them in material culture. Substantial progress has been made in understanding how our brain perceives and processes different categories of symbols, but our knowledge on how and when symbols permanently permeated the culture of our ancestors is still imprecise and speculative.

The archaeological layer in which the Blombos drawing was found also yielded other indicators of symbolic thinking, such as shell beads covered with ochre, and, more importantly, pieces of ochres engraved with abstract patterns. Some of these engravings closely resemble the one drawn on the silcrete flake.

"This demonstrates that early Homo sapiens in the southern Cape used different techniques to produce similar signs on different media," says Henshilwood. "This observation supports the hypothesis that these signs were symbolic in nature and represented an inherent aspect of the behaviourally modern world of these African Homo sapiens, the ancestors of all of us today."

A prehistoric thirst for craft beer

Evidence suggests that stone mortars from Raqefet Cave, Israel, were used in brewing cereal-based beer millennia before the establishment of sedentary villages and cereal agriculture

Elsevier

This is the site location and artifacts analyzed. (A) The location of Raqefet Cave and three additional Natufian sites in Mt. Carmel; (B) field photos of the studied boulder mortars (BM1,2) and the location of BM3 on the cave floor (scale bar and arrow: 20 cm); (C) a functional reconstruction of the mortars: a boulder mortar used to store plants in a basket with a stone slab on top, and a bedrock mortar used for pounding and cooking plants and brewing beer.

Credit: Credits to Elsevier, Journal of Archaeological Science: Reports Credits for photos: Dror Maayan; Graphic design: Anat Regev-Gisis

A new study published in the Journal of Archaeological Science: Reports suggests beer brewing practices existed in the Eastern Mediterranean over five millennia before the earliest known evidence, discovered in northern China. In an archaeological collaboration project between Stanford University in the United States, and University of Haifa, Israel, archeologists analyzed three stone mortars from a 13,000-year old Natufian burial cave site in Israel. Their analysis confirmed that these mortars were used for brewing of wheat/barley, as well as for food storage.

"Alcohol making and food storage were among the major technological innovations that eventually led to the development of civilizations in the world, and archaeological science is a powerful means to help reveal their origins and decode their contents," said Li Liu, PhD, Department of East Asian Languages and Cultures, Stanford University, USA. "We are excited to have the opportunity to present our findings, which shed new light on a deeper history of human society."

The earliest archaeological evidence for cereal-based beer brewing even before the advent of agriculture comes from the Natufians, semi-sedentary, foraging people, living in the Eastern Mediterranean between the Paleolithic and the Neolithic periods, following the last Ice Age. The Natufians at Raqefet Cave collected locally available plants, stored malted seeds, and made beer as a part of their rituals.

"The Natufian remains in Raqefet Cave never stop surprising us," said Prof. Dani Nadel, Zinman Institute of Archaeology, University of Haifa, Israel, who was also an excavator of the site. "We exposed a Natufian burial area with about 30 individuals; a wealth of small finds such as flint tools, animal bones and ground stone implements, and about 100 stone mortars and cupmarks. Some of the skeletons are well-preserved and provided direct dates and even human DNA, and we have evidence for flower burials and wakes by the graves.

"And now, with the production of beer, the Raqefet Cave remains provide a very vivid and colorful picture of Natufian lifeways, their technological capabilities and inventions."

After five seasons of excavations and a wide range of studies, the current study employed experimental archaeology, contextual examination, use-wear and residue analyses. The results indicate that the Natufians exploited at least seven plant types associated with the mortars, including wheat or barley, oat, legumes and bast fibers (including flax). They packed plant-foods in fiber-made containers and stored them in boulder mortars. They used bedrock mortars for pounding and cooking plant-foods, and for brewing wheat/barley-based beer, likely served in ritual feasts 13,000 years ago.
The use-wear patterns and microbotanical assemblage suggest that two of the three examined boulder mortars were used as storage containers for plant foods - including wheat/barley malts. Likely, they were covered with lids, probably made of stone slabs and other materials. The foods are likely to have been placed in baskets made of bast fibers for easy handing. The deep narrow shafts may have provided cool conditions suitable for storing food, especially for keeping cereal malts.

Combining use-wear and residue data, the third mortar studied was interpreted as a multi-functional vessel for food preparation, which included pounding plant foods and brewing wheat/barley-based beer, probably with legumes and other plants as additive ingredients.

The evidence of beer brewing at Raqefet Cave 13,000 years ago provides yet another example of the complex Natufian social and ritual realms. Beer brewing may have been, at least in part, an underlying motivation to cultivate cereals in the southern Levant, supporting the beer hypothesis proposed by archaeologists more than 60 years ago.

Understanding 6th-century barbarian social organization & migration

Applying a comprehensive analysis of genetic, historical, and archeological factors in two 6th-century barbarian cemeteries, researchers have gleaned new insights into a key era known as the Migration Period that laid the foundation for modern European society. Spanning the 4th to 8th centuries, this epoch followed the decline of the Western Roman Empire and was a time of major socioeconomic and cultural transformation in Europe. However, despite more than a century of scholarly work by historians and archaeologists, much about the period still remains unknown or is hotly debated, as reliable written accounts are lacking.

A paper, published today in Nature Communications, seeks to shed new light on how these communities were formed, how people lived, and how they interacted with the local populations they supposedly came to dominate. The international team of geneticists, historians, and archaeologists led by Professor Patrick Geary of the Institute for Advanced Study and Professor Krishna Veeramah of Stony Brook University in the U.S., Professor Johannes Krause of the Max Planck Institute for the Science of Human History in Jena, Germany, and Professor David Caramelli of the University of Florence in Italy, have for the first time sequenced the genomes of entire ancient cemeteries--one in Hungary and one in Italy.

This research provides the clearest picture yet of the lives and population movements of communities associated with the Longobards, a barbarian people that ruled most of Italy for more than two hundred years after invading from the Roman Province of Pannonia (modern-day Hungary) in 568 C.E. The team's data from the Hungarian cemetery, Szólád, almost doubles the number of ancient genomes obtained from a single ancient site to date. This in-depth genomic characterization allowed the team to examine the relationship between the genetic background of the community and the archaeological material left behind.

Professor Patrick Geary, of the Institute for Advanced Study, a senior author of the paper said, "Prior to this study, we would not have expected to observe such a strong relationship between genetic background and material culture. This appears to suggest that these particular communities contained a mix of individuals with different genetic backgrounds, that they were aware of these differences, and that it likely influenced their social identity."

A somewhat surprising result was that in both cemeteries, individuals buried with elaborate grave goods, like swords and shields for the men and beaded necklaces and broaches for the women, tended to have a genetic ancestry associated with modern northern and central Europeans today, while grave goods in individuals with more southern European-looking genomes were much less abundant. The individuals with abundant grave goods also tended to consume more protein rich diets.

"What we have presented in this study is a unique cross-discipline framework for the future," added Geary, "uniting experts from different disciplines to reinterpret and reconcile historical, genomic, isotopic, and archaeological evidence to enhance our knowledge of the past, compile new information on how populations move, how culture is transmitted, how to better understand identity, and new ways of understanding the complexity, heterogeneity, and malleability of Europe's population in the past and the present."

The approach also allowed researchers for the first time to reconstruct comprehensive genealogies of the people who were buried in these cemeteries, finding that family relations spanning multiple generations were likely key to establishing these communities. "It looks like both these cemeteries organized themselves around one or two large groups of biologically related kin, with the vast majority of these individuals being men" said Veeramah. "In addition, these related individuals tended to share the northern/central genetic ancestry associated with rich grave goods."

The team concluded that it was unusual to see this genetic ancestry type in Hungary and certainly in Italy in the 6th century. "Though we really need more data, our current results are consistent with the idea of barbarians migrating from north of Danube and east of the Rhine, which would suggest we are observing the invasions previously described by the Romans," said Veeramah. "It is also likely that social organization was based around large high-status male biological kinship groups, and these were key to establishing communities following the migration into Italy."

Veeramah, Caramelli, Krause, and Geary stressed that these results represented mere snapshots of the period and that more work in other cemeteries in other regions is vital for truly understanding this period. "It could be that we look at some new cemeteries 50 km away or that are 100 years older or younger and find very different patterns of social organization. People are complicated now, and they almost certainly were during the Migration Period," said Geary. "There are thousands of medieval cemeteries out there for us to look at. This is hopefully just the beginning of our work."

Genetic secrets of high-ranked warriors at a medieval German burial site

Researchers studying human remains of high-ranked warriors recovered from an Early Medieval Germanic cemetery have finally gleaned insight into these individuals' sex and kinship relationships.

These findings offer a unique understanding of the Alemanni, a group of Germanic tribes that occupied a region spanning parts of present-day Germany, France, Switzerland and Austria. After the Alemanni were defeated by the Franks in 497 AD, the tribes' burial practices changed, with households (familia) buried in richly furnished graves known as Adelsgrablege. An example of Alemannic Adelsgrablege can be seen in the 7th century AD Alemannic burial site at Niederstotzingen in southern Germany, where, decades ago, the skeletal remains of 13 individuals, as well as collections of goods, were uncovered from 12 graves.

Despite analysis on the site since its discovery in 1962, some questions remain: namely, the individuals' genetic sex, kinship and genetic origin. Using ancient genome-wide analyses techniques - including 1240K - Niall O'Sullivan and colleagues sought to reconstruct familial relationships of the Niederstotzingen individuals, as well as to estimate their genetic sex. At least 11 of the individuals were likely male, they say, suggesting that burial rites were sex-biased.

What's more, in terms of origin, the site is divided into two groups, the authors say: Niederstotzingen North, comprised of six individuals genetically most like modern northern and eastern European populations, and Niederstotzingen South, two individuals most similar to modern-day Mediterraneans, but genetically unrelated.

Of the Niederstotzingen North, five were second degree relatives. Finally, the strontium and oxygen isotope content of the individuals' dental enamel in the northern burials indicated that they were born locally, while the southern burials were born in other regions. These findings suggest that other social processes, such as personal fealty to powerful families, might have also influenced the composition of these cemeteries.

Evidence of 7,200-year-old cheese making found on the Dalmatian Coast

IMAGE: Selection of rhyta from Neolithic sites in Dalmatia. view more 

Credit: Sibenik City Museum

Analysis of fatty residue in pottery from the Dalmatian Coast of Croatia revealed evidence of fermented dairy products -- soft cheeses and yogurts -- from about 7,200 years ago, according to an international team of researchers.

"This pushes back cheese-making by 4,000 years," said Sarah B. McClure, associate professor of anthropology.

The presence of milk in pottery in this area is seen as early as 7,700 years ago, 500 years earlier than fermented products, said the researchers. DNA analysis of the populations in this area indicate that the adults were lactose-intolerant, but the children remained able to consume milk comfortably up to the age of ten.

"First, we have milking around, and it was probably geared for kids because it is a good source of hydration and is relatively pathogen-free," said McClure. "It wouldn't be a surprise for people to give children milk from another mammal."

However, about 500 years later, the researchers see a shift not only from pure milk to fermented products, but also in the style and form of pottery vessels.

"Cheese production is important enough that people are making new types of kitchenware," said McClure. "We are seeing that cultural shift."

When only meat, fish and some milk residue is found in pottery, during the Early Neolithic, the pottery is a style called "Impressed Ware" found throughout the area.

500 years later, in the Middle Neolithic, another pottery style using different technology existed -- Danilo pottery -- which defines the era in this area and includes plates and bowls. There are three subtypes of Danilo pottery.

Figulina makes up five percent of this type and is highly fired and buff-colored, often slipped and decorated. All this pottery contained milk residue. The other Danilo wares contained animal fats and fresh water fish residue.

Rhyta, which are footed vessels with round bodies and are often animal- or human-shaped, have large openings on the sides and distinctive handles. The researchers found that three of the four rhyta in their sample showed evidence of cheese.

The third category of Danilo ware is sieves, which are often used in cheese-making to strain treated milk when it separates into curds and whey. Three of the four sieves in the sample showed evidence of secondary milk processing into either cheese or other fermented dairy products.

"This is the earliest documented lipid residue evidence for fermented dairy in the Mediterranean region, and among the earliest documented anywhere to date," the researchers report today (Sept. 5) in PLOS One.

The researchers looked at pottery from two sites in Croatia in Dalmatia -- Pokrovnik and Danilo Bitinj. When possible, they selected samples from unwashed pottery, but because some pottery forms are rarer, used washed samples for the sieves. They tested the pottery residue for carbon isotopes, which can indicate the type of fat and can distinguish between meat, fish, milk and fermented milk products. They used radiocarbon dating on bone and seeds to determine the pottery's age.

According to the researchers, dairying -- and especially cheese and fermented milk products -- may have opened northern European areas for farming because it reduced infant mortality and allowed for earlier weaning, decreasing the birth interval and potentially increasing population. It also supplied a storable form of nutrition for adults, because the fermentation of cheese and yogurt reduce the lactose content of milk products, making it palatable for adults as well as children.

With a food source that could buffer the risk of farming in colder northern climates, farmers could expand their territories.