The economy of hunter gatherers in the Mediterranean coasts between the Pleistocene and Holocene included exploitation of marine environment

The economy of hunter gatherers in the Mediterranean coasts between the Pleistocene and Holocene included exploitation of marine environment

The study carried out by the Universitat Jaume I, the Municipal Archaeological Museum of Cartagena, the Provincial Council of Castellón and the University of Barcelona confirms that its use during the Mesolithic period was greater than previously thought.
Pleistocene Holocene marine
The map with the sites

New discoveries and material reviews by an inter-institutional research team have confirmed that the economic context at the end of the transition between the Pleistocene and the Holocene on the Mediterranean coast were richer, more complex and more varied than was previously thought. The exploitation of marine resources was not limited to the harvesting of molluscs, but also included fishing, although not many remains have been preserved, probably because the preservation of these types of materials is more delicate or because of the eating habits of ancient human populations.

Until a few years ago, little was known about the characteristics of the economy of hunter-gatherer groups in the Mediterranean during the transition from the Pleistocene (the glacial era, the Palaeolithic) to the Holocene (post-glacial, the time we live in today). Most of the studies carried out in the Iberian Peninsula suggested that the sites of marine exploitation were located particularly in the Cantabrian and Atlantic area, but the new data and studies provided by the research team can change this paradigm.

The research and analysis work, whose conclusions have been published in The Journal of Island and Coastal Archaeology, has involved Dídac Román, doctoral researcher of excellence of the GenT Plan of the Valencian Regional Government in the Department of History, Geography and Art at the Universitat Jaume I and the Pre-EINA research group; Miguel Martínez Andreu from the Municipal Archaeological Museum of Cartagena; Gustau Aguilella from the Archaeological and Prehistoric Research Service of the Castellón Provincial Council and Josep Maria Fullola and Jordi Nadal from the Prehistoric Studies and Research Seminar (SERP) of the University of Barcelona.

Data collected during the research confirm that the use of marine resources during the late Palaeolithic and Mesolithic on the Iberian Mediterranean coast was clearly more common than was previously thought with the data available at the time. The difference regarding the presence of less evidence than in the case of the Cantabrian and Atlantic coasts, where there are more hunter-gatherer-fisherman sites catalogued, could be due to different reasons: greater richness and diversity of life due to the cold marine currents, more abundant in nutrients; presence of tides and other environmental factors and better preservation of the sites over time thanks to a coastal platform and a steeper coastline that protected them from the progressive flooding of the environment with the melting of the poles during the Holocene.

Dídac Román, Miguel Martínez-Andreu, Gustau Aguilella, Josep Maria Fullola & Jordi Nadal (2020): “Shellfish collectors on the seashore: the exploitation of the marine environment between the end of the Paleolithic and the Mesolithic in the Mediterranean Iberia”, The Journal of Island and Coastal Archaeology.

Press release from Asociación RUVID

 

The new findings and examinations of material carried out by a multi-institutional research proved the economic context at the end of the transition between the Plesitocene and the Holocene in the Mediterranean coasts to be richer, more complex and varied than what we thought. Exploitation of marine resources was not limited to a recollection of molluscs, but it also included fishing, although not many remains were preserved, probably because the preservation of such materials is more delicate or due to the eating habits of ancient human populations.

The conclusions of this research and analytical study have been published in The Journal of Island and Coastal Archaeology. Among the participants in the study are Dídac Román, researcher at Plan Gent of the Valencian Government in the Department of History, Geography and Arts of the University Jaume I and the research group Pre-EINA; Miguel Martínez Andreu, from the Archaeological Museum of Cartagena; Gustay Aguilella, from the Service of Archaeological and Prehistoric Research of Diputación de Castellón, and Josep Maria Fullola and Jordi Nadal, from the Prehistoric Studies and Research Seminar (SERP) of the University of Barcelona, in which the first signer of the study participates as well.

Until some years ago, we did not know much about the economic features of hunter-gatherer groups in the Mediterranean during the transition from the Pleistocene (ice age, Palaeolithic), to the Holocene (post-glaciation, current moment we live in). Most of the studies carried out in the Iberian Peninsula suggested that the areas of marine exploitation were specifically in the Cantabrian and Atlantic areas, but new data and studies conducted by the research team change this paradigm now.

The collected data during the research study states that the use of marine resources at the end of the Palaeolithic and Mesolithic in the Iberian Mediterranean coasts was more common than what people thought with the existing data. The difference regarding the presence of less evidence in the Cantabrian and Atlantic coasts, where there are more areas of hunter-gatherer-fishers, could be due to several reasons: more richness and life diversity due to cold marine currents, more nutrients; presence of tides and other environmental factors, and a better preservation of the areas over time (thanks to a littoral platform and an abrupt coast that protected these from a progressive flood of the environment with the melting of the poles during the Holocene).

SERP studies and Catalan records

Although the results of the article resulted from an interdisciplinary study, in which members of different research centres collaborated to obtain data from all regions, SERP-UB has led two essential aspects in this study. On the one hand, the analysis of the bioarchaeological elements –mainly faunistic remains–, on which the conclusions are based in order to show the importance of the utility of the marine resources by the communities of hunter-gatherers in the study area. On the other hand, obtaining radiocarbon dating in different sites, some excavations from years ago and others which are currently active. These datings are the ones to enable researchers to date the exploitation marine events between 13,000 and 7,000 years ago approximately. Moreover, the SERP studies carried out the interpretation of data in the Catalan area, with the examination of material from old excavations that are now in different museums.

Among these are the collections in the Archaeology Museum Salvador Vilaseca in Reus, which features material from key sites for the current study, such as Camping Salou (Salou) or the cave Cova del Solà d’en Pep (Hospitalet de l’Infant), excavated by Salvador Vilaseca. Although they are not mentioned in the article, other synchronic archaeological excavations are now a target excavation for SERP in Catalonia. The objective is to go beyond the evaluation of the importance of the subsistence of marine origins in the coastal areas but also to value the type of resources among the last populations of hunter-gatherers in the area. Thus, shells used as ornaments have been found in Priorat (El Filador and Hort de la Boquera), Moianès (Balma del Gai), La Noguera (Cova del Parco) and even in Cerdanya (Montlleó).

Ten Mediterranean sites

Researchers analysed remains from ten archaeological sites, located over the 800 kilometers of the Mediterranean coast, from Tarragona to Málaga, specifically La Cativera, Camping Salou and Solà d’en Pep (Tarragona); L’Assut and La Cova (Castellón); El Collado (Valencia); Algarrobo, Caballo and La Higuera (Murcia)and Nerja (Málaga). Contrary to what people thought, places in the south show a larger diversity of resources (the most paradigmatic is in the cave in Nerja). This would happen due to the entrance of waters from the Atlantic Ocean, its proximity, and it can be proved because there is presence of species such as L. Obtusata and species from colder climates such as cod species M. Aeglefinus and O. Pollachius. The Mediterranean is poorer regarding its biology due to salinity, temperature, lack of nutrients and unpredictable tides.

In general, the exploitation of marine resources (mainly molluscs) is related to the exploitation of terrestrial invertebrates and the presence of mammal remains (deer, Iberian ibex, rabbits, among others). However, researchers confirmed there is a decrease in terrestrial invertebrates in favour of marine resources over time. This feature has been observed in those places that conserved remains over long periods of time such as the cave in Nerja, or studied areas that show an older chronology such as Càmping Salou, La Cova, Caballo, Algarrobo and La Higuera. Among the studied molluscs are sea urchins (Solà d’en Pep and Nerja), crustaceans (Caballo), and cephalopods (Nerja), and among fish, the red sea bream is the most found in places with seasonal marsh (El Collado, Caballo and La Higuera), varieties of cod in Nerja and marine birds and mammals (Monachus and Deplhinus).

Another important aspect of the study was to evaluate whether the location and exploitation could be linked to the proximity to the sea, but according to the obtained data, at the time of occupation, these places were not exactly coastal areas (La Cova and El Collado, for instance); their inhabitants had to move about thirty kilometres to get supplies.

The research team used data on the fluctuations of the sea level during its activity in the late Palaeolithic and Mesolithic to calculate the distance to the coast. To estimate the distance, they combined different digital models of the area with bathymetry, which enabled a simulation of different positions of the coast in ranks, and researchers could specify whether it was within the two-hour isochrone of the sites, a distance considered the common area where hunter-gatherers carried out their activities.

The extension of the continental platform and the shape of the coast has been important for this research. The south east area of the peninsula is a relatively sheer area with a continental platform that has deep cliffs, but these features have protected it from important orographic changes. The central area (Tarragona, Castellón and Valencia) is completely different. The sedimentation of the Ebro Riber conditions the existence of a smooth and low altitude in the coast with a big continental platform that has changed its orography due to marine regression and transgression.

Reference article:

Dídac Román, Miguel Martínez-Andreu, Gustau Aguilella, Josep Maria Fullola & Jordi Nadal (2020): “Shellfish collectors donde the seashore: The exploitation of the marino environment between the end of the Paleolithic and the Mesolithic in the Mediterranean Iberia”The Journal of Island and Coastal Archaeology. tandfonline.com/doi/full/10.1080/15564894.2020.1755395

 

Press release from the University of Barcelona.


Neanderthals: pioneers in the use of marine resources

Neanderthals ate mussels, fish, and seals too

International research team with participation from University of Göttingen find it wasn't just Homo sapiens who sourced food from the sea -- impact on cognitive abilities suspected

Neanderthals marine
View on the Figueira Brava cave with its three entrances. Credits: João Zilhão

Over 80,000 years ago, Neanderthals were already feeding themselves regularly on mussels, fish and other marine life. The first robust evidence of this has been found by an international research team with the participation of the University of Göttingen during an excavation in the cave of Figueira Brava in Portugal. Dr Dirk Hoffmann at the Göttingen Isotope Geology Department dated flowstone layers - calcite deposits that form like stalagmites from dripping water - using the uranium-thorium method, and was thus able to determine the age of the excavation layers to between 86,000 and 106,000 years. This means that the layers date from the period in which the Neanderthals settled in Europe. The use of the sea as a source of food at that time has so far only been attributed to anatomically modern humans (Homo sapiens) in Africa. The results of the study were published in the journal Science.

Cracked-open and burnt fragments of pincers of the edible crab (cancer pagurus). Credits: João Zilhão

The cave of Figueira Brava is located 30 kilometres south of Lisbon on the slopes of the Serra da Arrábida. Today it is located directly on the waterfront, but at that time it was up to two kilometres from the coast. The research team, coordinated by the first author of the study, Professor João Zilhão from the University of Barcelona, found that the Neanderthals living there were able to routinely harvest mussels and fish, and to hunt seals. Their diet included mussels, crustaceans and fish as well as waterfowl and marine mammals such as dolphins and seals. Food from the sea is rich in omega-3 fatty acids and other fatty acids that promote the development of brain tissue.

Until now, it has always been suspected that this consumption increased the cognitive abilities of the human populations in Africa. "Among other influences, this could explain the early appearance of a culture of modern people that used symbolic artefacts, such as body painting with ochre, the use of ornaments or the decoration of containers made of ostrich eggs with geometric motifs," explains Hoffmann. "Such behaviour reflects human's capacity for abstract thought and communication through symbols, which also contributed to the emergence of more organised and complex societies of modern humans".

Neanderthals marine
Horizontal exposure of a mussel shell bed. Credits: João Zilhão

The recent results of the excavation of Figueira Brava now confirm that if the habitual consumption of marine life played an important role in the development of cognitive abilities, this is as true for Neanderthals as it is for anatomically modern humans. Hoffmann and his co-authors previously found that Neanderthals made cave paintings in three caves on the Iberian Peninsula more than 65,000 years ago and that perforated and painted shells must also be attributed to the Neanderthals.

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Original publication: J. Zilhão et al., Last Interglacial Iberian Neandertals as fisher-hunter-gatherers, Science, 10.1126/science.aaz7943

See: https://science.sciencemag.org/cgi/doi/10.1126/science.aaz7943

 

 

Press release from the University of Göttingen

 

Science publishes study on Neanderthals as pioneers in marine resource exploitation

Neanderthals marine
Cracked-open and burnt fragments of Cancer pagurus pincer? Credits: José Paulo Ruas © João Zilhão

The journal Science has published a study led by the ICREA researcher João Zilhão, from the University of Barcelona, which presents the results of the excavation in Cueva de Figueira Brava, Portugal, which was used as shelter by Neanderthal populations about between 86 and 106 thousand years ago. The study reveals fishing and shellfish-gathering contributed significantly to the subsistence economy of the inhabitants of Figueira Brava. The relevance of this discovery lies in the fact that so far, there were not many signs of these practices as common among Neanderthals.

Regarding the consequences of this study, João Zilhão notes that "an influent model on our origins suggests the common consumption of water resources -rich in Omega3 and other fatty acids that favour the development of brain tissues- would have increased the cognitive skills of modern anatomy humans. That is, those humans who, in Africa, were contemporaries of Neanderthals and are usually regarded as the only ancestors of the current Homo sapiens". But the results of the excavation of Figueira Brava state that, if this common consumption of marine resources played an important role in the development of cognitive skills, it did so on the entire humanity, including Neanderthals, and not only the African population that spread later".

Zilhão member of the Prehistoric Studies and Research Seminar (SERP-UB), lists the research study in the line of "proof that accumulated over the last decade to show Neanderthals had a symbolic material culture". Two years ago, in 2018, the journals Science and Science Advances published two studies co-led by João Zilhão which showed that more than 65,000 years ago, Neanderthals made cave paintings in at least three caves in the Iberian Peninsula: La Pasiega, Maltravieso and Ardales (Science). Furthermore, more than 115,000 years ago, they used perforated marine shells and with ocher remains, such as the ones from Cueva de los Aviones (Murcia, Spain), as pendants and shell containers with residues of complex mixes of pigment (Science Advances). These findings, the most recent one being the one in Figueira Brava, "support a view on human evolution in which the known fossil variants, such as Neanderthals' in Europe and its African anatomy contemporaries -more similar to ours-, should be understood as remains from our ancestors, not as different higher-lower species", notes Zilhão.

Pieces of clam Ruditapes decussatus, found in the site. Credits: Mariana Nabais © João Zilhão

A 50% of the diet of the inhabitants in Figueira Brava was built by coastal resources: molluscs (limpet, mussel and clams; crustaceans (brown crab and spider crab); fish (shark, eel, sea bream, mullet); birds (mallard, common scoter, goose, cormorant, gannet, shag, auk, egret, loon), and mammals (dolphin, seal). This was completed with the hunt of deer, goats, horses, aurochs and other small preys such as tortoises. Among the other carbonised plants were olive trees, vines, fig trees and other Mediterranean climate typical species, among which the most abundant was the stone pine -its wood was used as combustible. Pine forests were exploited as fruit tree gardens: mature pines, albeit closed, were taken from the branches and stored in the cave, where the fire could open them so as to take the pines.

The study also provides other results, such as the idea of the concept of Neanderthals as cold and tundra peoples, experts on hunting mammoths, rhinos, buffalos and reindeers, is biased. "Most Neanderthals would have lived in southern regions, specially in Italy and in the Iberian Peninsula, and its lifestyle would have been very similar to those in Figueira Brava", notes Zilhão.

Another important affirmation in the study is the familiarity of humans with the sea and its resources as something older and wider than what was thought. "This could probably help explain how, between 45,000 and 50,000 years ago, humans could cross the Timor Sea to colonize Australia and New Guinea, and then, about 30,000 years ago, the closest islands to the western Pacific", says Zilhão.

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Article reference:

J. Zilhão, D. E. Angelucci, M. Araújo Igreja, L. J. Arnold, E. Badal, P. Callapez, J. L. Cardoso, F. d'Errico, J. Daura, M. Demuro, M. Deschamps, C. Dupont, S. Gabriel, D. L. Hoffmann, P. Legoinha, H. Matias, A. M. Monge Soares, M. Nabais, P. Portela, A. Queffelec, F. Rodrigues, P. Souto. "Last Interglacial Iberian Neandertals as fisher-hunter-gatherers", Science, 367, March 27, 2020.

 

Press release from the University of Barcelona

 

Neanderthals: Pioneers in the use of marine resources

Neanderthals slurping seashells by the seashore? This scene may startle those accustomed to imagining Homo neanderthalensis as a people of cold climes who hunted large herbivores. Yet an international team including scientists from three laboratories affiliated with the CNRS and partner institutions* have just demonstrated that Neanderthals hunted, fished, and gathered prodigious volumes of seafood and other marine animals: they discovered remains of molluscs, crustaceans, fish, birds, and mammals in a Portuguese cave (Figueira Brava) occupied by Neanderthals between 106,000 and 86,000 BCE. The diversity of marine food resources found there even exceeds that observed at other, much more recent Portuguese sites, dated to 9,000-7,500 BCE. The team's findings, published in Science (27 March 2020), suggest that many Neanderthal groups--living in Mediterranean climates far from the mammoth hunts of the frigid steppes--shared these dietary habitats.

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Researchers from Centre de recherche en archéologie, archéosciences, Histoire (CNRS/Université de Rennes), from De la préhistoire à l'actuel : culture, environnement et anthropologie laboratory (CNRS/Université de Bordeaux/Ministère de la Culture) and Travaux de recherches archéologiques sur les cultures, les espaces et les sociétés laboratory (CNRS/Université de Toulouse Jean Jaurès/Ministère de la Culture).

 

Press release from the CNRS


Dramatic change in ancient nomad diets coincides with expansion of networks across Eurasia

Dramatic change in ancient nomad diets coincides with expansion of networks across Eurasia

nomad pastoralists diets
Map of millet and wheat/barley consumption over time: a) 1000-500 cal BC, b) 500-200 cal BC, and c) 200 BC-AD 400. Credit: Map of millet and wheat/barley consumption over time: a) 1000-500 cal BC, b) 500-200 cal BC, and c) 200 BC-AD 400

A meta-analysis of dietary information recorded in the bones of ancient animals and humans recovered from sites scattered across the Eurasian steppe, from the Caucasus region to Mongolia, demonstrates that pastoralists spread domesticated crops across the steppe through their trade and social networks. Researchers from Kiel University sifted through previously published stable isotopic data and applied new quantitative analyses that calibrate human dietary intake against environmental inputs. The results have allowed them to better isolate the timing of the incorporation of agricultural products into the diets of pastoral nomads and, crucially, link burgeoning socio-political networks to this dietary transformation.

Through a big data project that explored over a thousand stable isotope data points, researchers were able to find evidence for an early transition to agriculture - based on dietary intake across Eurasia. "Our understanding of the pace of crop transmission across the Eurasian steppe has been surprisingly unclear due in part to a focus on the excavation of cemeteries, rather than settlements where people threw out their food," says Alicia Ventresca Miller, lead author, formerly of Kiel University and currently at the Max Planck Institute for the Science of Human History. "Even when settlement sites are excavated, the preservation of carbonized seed remains is often poor. This is what makes stable isotope analyses of human remains from this region so valuable - it provides direct insights into the dietary dynamics of ancient pastoralists who inhabited diverse environments."

Millet spreads across the Eurasian steppe

Millet, originally domesticated in China, appears to have been occasionally consumed at low levels by pastoralists inhabiting the far-flung regions of Siberia and southeastern Kazakhstan, possibly as early as the late third millennium. This initial uptake of millet coincided with the expansion of trans-regional networks across the steppe, when objects and ideas were first regularly exchanged over long-distances.

However, it was not until a thousand years later that millet became a regular feature of pastoralist diets. This timing coincides with the intensification of complex political structures at the transition to the Iron Age. Burgeoning socio-political confederations drove a marked increase in the exchange of costly prestige goods, which strengthened political networks - and facilitated the transfer of cultigens.

Wheat and Barley in the Trans-Urals

Despite taking part in these political networks, groups in the Trans-Urals invested in wheat and barley farming rather than millet. A dietary focus on wheat and barley may have been due to different farming techniques, greater water availability, or a higher value on these cultigens. "Our research suggests that cultigens were converted from a rare luxury during the Bronze Age to a medium demarcating elite participation in political networks during the Iron Age," states Cheryl Makarewicz of Kiel University.

Regional variation in millet consumption

While herding of livestock was widespread, not all regions adopted millet. In southwest Siberia, dietary intake was focused on pastoral animal products and locally available wild plants and fish. In contrast, the delayed adoption of millet by populations in Mongolia during the Late Iron Age coincides with the rise of the Xiongnu nomadic empire. "This is particularly interesting because it suggests that communities in Mongolia and Siberia opted out of the transition to millet agriculture, while continuing to engage with neighboring groups," explains Ventresca Miller.

This study shows the great potential of using the available isotope record to provide evidence for human dietary intake in areas where paleobotany is understudied. Further research should clarify the exact type of grains, for example broomcorn or foxtail millet, were fundamental to the shift in dietary intake and how networks of exchange linked different regions.

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Original publication:

Ventresca Miller and Makarewicz, Intensification in pastoralist cereal use coincides with the expansion of trans-regional networks in the Eurasian Steppe, Scientific Reports (2019). DOI: https://doi.org/10.1038/s41598-018-35758-w

 

Press release from Kiel University / Christian-Albrechts-Universität zu Kiel


Earliest evidence of the cooking and eating of starch

Earliest evidence of the cooking and eating of starch

Early human beings who lived around 120,000 years ago in South Africa were 'ecological geniuses' who were able to exploit their environment intelligently for suitable food and medicines

starch Klasies River Cave South Africa
The Klasies River cave in the southern Cape of South Africa. Credit: Wits University

New discoveries made at the Klasies River Cave in South Africa's southern Cape, where charred food remains from hearths were found, provide the first archaeological evidence that anatomically modern humans were roasting and eating plant starches, such as those from tubers and rhizomes, as early as 120,000 years ago.

The new research by an international team of archaeologists, published in the Journal of Human Evolution, provides archaeological evidence that has previously been lacking to support the hypothesis that the duplication of the starch digestion genes is an adaptive response to an increased starch diet.

"This is very exciting. The genetic and biological evidence previously suggested that early humans would have been eating starches, but this research had not been done before," says Lead author Cynthia Larbey of the Department of Archaeology at the University of Cambridge. The work is part of a systemic multidisciplinary investigation into the role that plants and fire played in the lives of Middle Stone Age communities.

The interdisciplinary team searched for and analysed undisturbed hearths at the Klasies River archaeological site.

"Our results showed that these small ashy hearths were used for cooking food and starchy roots and tubers were clearly part of their diet, from the earliest levels at around 120,000 years ago through to 65,000 years ago," says Larbey. "Despite changes in hunting strategies and stone tool technologies, they were still cooking roots and tubers."

starch Klasies River Cave South Africa
Cynthia Larbey points to an area where parenchyma were found in 65,000 year old hearths at Klasies River Cave. Credit: Wits University

Professor Sarah Wurz from the School of Geography, Archaeology and Environmental Studies at the University of the Witwatersrand in Johannesburg, South Africa (Wits University) and principal investigator of the site says the research shows that "early human beings followed a balanced diet and that they were ecological geniuses, able to exploit their environments intelligently for suitable foods and perhaps medicines".

By combining cooked roots and tubers as a staple with protein and fats from shellfish, fish, small and large fauna, these communities were able to optimally adapt to their environment, indicating great ecological intelligence as early as 120 000 years ago.

"Starch diet isn't something that happens when we started farming, but rather, is as old as humans themselves," says Larbey. Farming in Africa only started in the last 10 000 years of human existence.

Humans living in South Africa 120 000 years ago formed and lived in small bands.

"Evidence from Klasies River, where several human skull fragments and two maxillary fragments dating 120 000 years ago occur, show that humans living in that time period looked like modern humans of today. However, they were somewhat more robust," says Wurz.

Klasies River is a very famous early human occupation site on the Cape coast of South Africa excavated by Wurz, who, along with Susan Mentzer of the Senckenberg Institute and Eberhard Karls Universität Tübingen, investigated the small (c. 30cm in diameter) hearths.

The research to look for the plant materials in the hearths was inspired by Prof Hilary Deacon, who passed on the Directorship of the Klasies River site on to Wurz. Deacon has done groundbreaking work at the site and in the 1990's pointed out that there would be plant material in and around the hearths. However, at the time, the micro methods were not available to test this hypothesis.

The Klasies River cave in the southern Cape of South Africa. Credit: Wits University

Press release from the University of the Witwatersrand


Ancient fish ponds in the Bolivian savanna supported human settlement

Ancient fish ponds in the Bolivian savanna supported human settlement

Detailed study of taxa supports intentional maintenance of fish habitat for food

Interior of circular pond with canal exit visible in the center of the far margin. Credit: Prestes-Carneiro et al., 2019

A network of fish ponds supported a permanent human settlement in the seasonal drylands of Bolivia more than one thousand years ago, according to a new study published May 15, 2019 in the open-access journal PLOS ONE by Gabriela Prestes-Carneiro of Federal University of Western Para, Brazil, and colleagues. The study is the first to document the full range of fish species likely kept in these constructed ponds, and provides new insights into how humans modified the savannah environment to cope with the months-long droughts that characterize this region of the Amazon Basin.

The Llanos de Mojos region in central Bolivia is a vast plain which receives flooding rains from October to April, and then virtually no precipitation the rest of the year. Beginning about 500 AD, humans began to create monumental earthen mounds in the region, on which permanent settlements were established. One, called Loma Salavtierra, located more than 50 kilometers from the nearest major river, has become an important archaeological site. Previous work has established the existence of a series of shallow ponds rimmed by low earthen walls and connected by canals, which are believed to have captured rainfall and stored it throughout the dry season, potentially built to serve multiple purposes including water storage, drainage, and fish management.

fish ponds Bolivia
Fish remains from Loma Salvatierra. Credit: Prestes-Carneiro et al., 2019

In the current study, the authors conducted osteological and taxonomic identifications on the remains of over 17,000 fish found in midden piles at the site with the aid of a comparative collection. They identified more than 35 different taxa of fish, with four types of fish predominating: swamp-eels, armored catfish, lungfish, and tiger-fish, all of which are adapted to conditions of low oxygen and fluctuating water levels, as would be expected to arise in the ponds during the long dry period between annual rains.

Together with evidence of similar pond networks elsewhere in the region, the authors suggest that their results point to the use of these ponds for harvesting fish year-round, far from any rivers, permanent natural ponds, or other open-water habitat. Further studies will be needed to investigate fish storage and holding activities, and whether these activities changed in response to precipitation and landscape fluctuations.

The authors add: "The savanna, in contrast to the large Amazonian rivers, presents a distinct set of fishing habitats where humans likely established specific fishing strategies."

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