̽��ֱ�� of Cambridge - hunter-gatherers

Hunter-gatherer childhoods may offer clues to improving education and wellbeing

ta385 — Tue, 07 Mar 2023 17:30:00 +0000

̽��ֱ��benefits of skin-to-skin contact for both parents and infants are already recognised, but other behaviours common in hunter-gatherer societies may also benefit families in economically developed countries, a Cambridge researcher suggests.

Parents and children may, for instance, benefit from a larger network of people being involved in care-giving, as seen in hunter-gatherer societies. Increasing staff-to-child ratios in nurseries to bring them closer to highly attentive hunter-gatherer ratios could support learning and wellbeing. And more peer-to-peer, active and mixed-age learning, as seen in hunter-gatherer communities, may help school children in developed countries.

Published today in the Journal of Child Psychology and Psychiatry, the study by Dr Nikhil Chaudhary, an evolutionary anthropologist in Cambridge's Department of Archaeology, and Dr Annie Swanepoel, a child psychiatrist, calls for new research into child mental health in hunter-gatherer societies. They explore the possibility that some common aspects of hunter-gatherer childhoods could help families in economically developed countries. Eventually, hunter-gatherer behaviours could inform ‘experimental intervention trials’ in homes, schools and nurseries.

̽��ֱ��authors acknowledge that children living in hunter-gatherer societies live in very different environments and circumstances than those in developed countries. They also stress that hunter-gatherer children invariably face many difficulties that are not experienced in developed countries and, therefore, caution that these childhoods should not be idealised.

Drawing on his own observations of the BaYaka people in Congo and the extensive research of anthropologists studying other hunter-gatherer societies, Dr Chaudhary highlights major differences in the ways in which hunter-gatherer children are cared for compared to their peers in developed countries. He stresses that “contemporary hunter-gatherers must not be thought of as ‘living fossils’, and while their ways of life may offer some clues about our prehistory, they are still very much modern populations each with a unique cultural and demographic history”.

Physical contact and attentiveness

Despite increasing uptake of baby carriers and baby massage in developed countries, levels of physical contact with infants remain far higher in hunter-gatherer societies. In Botswana, for instance, 10-20 week old !Kung infants are in physical contact with someone for around 90% of daylight hours, and almost 100% of crying bouts are responded to, almost always with comforting or nursing – scolding is extremely rare.

̽��ֱ��study points out that this exceptionally attentive childcare is made possible because of the major role played by non-parental caregivers, or ‘alloparents’, which is far rarer in developed countries.

Non-parental caregivers

In many hunter-gatherer societies, alloparents provide almost half of a child’s care. A previous study found that in the DRC, Efe infants have 14 alloparents a day by the time they are 18 weeks old, and are passed between caregivers eight times an hour.

Dr Chaudhary said: “Parents now have much less childcare support from their familial and social networks than would likely have been the case during most of our evolutionary history. Such differences seem likely to create the kind of evolutionary mismatches that could be harmful to both caregivers and children.”

“ ̽��ֱ��availability of other caregivers can reduce the negative impacts of stress within the nuclear family, and the risk of maternal depression, which has knock-on effects for child wellbeing and cognitive development.”

̽��ֱ��study emphasises that alloparenting is a core human adaptation, contradicting ‘intensive mothering’ narratives which emphasise that mothers should use their maternal instincts to manage childcare alone. Dr Chaudhary and Dr Swanepoel write that ‘such narratives can lead to maternal exhaustion and have dangerous consequences’.

Care-giving ratios

̽��ֱ��study points out that communal living in hunter-gatherer societies results in a very high ratio of available caregivers to infants/toddlers, which can even exceed 10:1.

This contrasts starkly with the nuclear family unit, and even more so with nursery settings, in developed countries. According to the UK’s Department of Education regulations, nurseries require ratios of 1 carer to 3 children aged under 2 years, or 1 carer to 4 children aged 2-3.

Dr Chaudhary said: “Almost all day, hunter-gatherer infants and toddlers have a capable caregiver within a couple of metres of them. From the infant’s perspective, that proximity and responsiveness, is very different from what is experienced in many nursery settings in the UK.”

“If that ratio is stretched even thinner, we need to consider the possibility that this could have impacts on children's wellbeing.”

Children providing care and mixed-age active learning

In hunter-gatherer societies, children play a significantly bigger role in providing care to infants and toddlers than is the case in developed countries. In some communities they begin providing some childcare from the age of four and are capable of sensitive caregiving; and it is common to see older, but still pre-adolescent children looking after infants.

By contrast, the NSPCC in the UK recommends that when leaving pre-adolescent children at home, babysitters should be in their late teens at least.

Dr Chaudhary said: “In developed countries, children are busy with schooling and may have less opportunity to develop caregiving competence. However, we should at least explore the possibility that older siblings could play a greater role in supporting their parents, which might also enhance their own social development.”

̽��ֱ��study also points out that instructive teaching is rare in hunter-gatherer societies and that infants primarily learn via observation and imitation. From around the age of two, hunter-gatherer children spend large portions of the day in mixed-age (2-16) ‘playgroups’ without adult supervision. There, they learn from one another, acquiring skills and knowledge collaboratively via highly active play practice and exploration.

Learning and play are two sides of the same coin, which contrasts with the lesson-time / play-time dichotomy of schooling in the UK and other developed countries.

Dr Chaudhary and Dr Swanepoel note that “Classroom schooling is often at odds with the modes of learning typical of human evolutionary history.” ̽��ֱ��study acknowledges that children living in hunter-gatherer societies live in very different environments and circumstances than those in developed countries:

“Foraging skills are very different to those required to make a living in market-economies, and classroom teaching is certainly necessary to learn the latter. But children may possess certain psychological learning adaptations that can be practically harnessed in some aspects of their schooling. When peer and active learning can be incorporated, they have been shown to improve motivation and performance, and reduce stress.” ̽��ֱ��authors also highlight that physical activity interventions have been shown to aid performance among students diagnosed with ADHD.

Further research

̽��ֱ��study calls for more research into children’s mental health in hunter-gatherer societies to test whether the hypothesised evolutionary mismatches actually exist. If they do, such insights could then be used to direct experimental intervention trials in developed countries.

Working with a team from the Royal College of Psychiatrists, Dr Chaudhary and Dr Swanepoel hope that greater collaboration between evolutionary anthropologists and child psychiatrists/psychologists can help to advance our understanding of the conditions that children need to thrive.

Reference

N Chaudhary and A Swanepoel, ‘What Can We Learn from Hunter-Gatherers about Children’s Mental Health? An Evolutionary Perspective’, Journal of Child Psychology and Psychiatry (2023). DOI: 10.1111/jcpp.13773

Hunter-gatherers can help us understand the conditions that children may be psychologically adapted to because we lived as hunter-gatherers for 95% of our evolutionary history. Paying greater attention to hunter-gatherer childhoods may help economically developed countries improve education and wellbeing.

Parents now have much less childcare support from their familial and social networks than would likely have been the case during most of our evolutionary history

Nikhil Chaudhary

Image courtesy of Nikhil Chaudhary

BaYaka camp in Congo. Image courtesy of Nikhil Chaudhary

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Gendered play in hunter-gatherer children strongly influenced by community demographics

sc604 — Thu, 26 Sep 2019 05:15:00 +0000

Based on observations of more than one hundred children in two different hunter-gatherer communities in sub-Saharan Africa, an international team, led by researchers from the ̽��ֱ�� of Cambridge, found that younger children were generally more likely to play in mixed-gender groups. In small communities, however, boys and girls were more likely to play together, likely due to a lack of playmates of the same gender.

As children get older, they begin to imitate the adults around them and learn culturally-specific gender roles through play. ̽��ֱ��results, reported in the journal Child Development, demonstrate the similarities with and differences from Western societies, and the importance of context when studying how children acquire various gendered behaviours.

Play is a universal feature of human childhood, and contributes to children’s cultural learning, including gender roles. Studies have shown that children are more likely to play in same-gender groups, with boys more likely to participate in vigorous ‘rough-and-tumble’ play, and girls more likely to pretend in pretense, or imaginary, play such as doll play.

However, as most studies on the development of gender focus on children from Western societies, it is difficult to determine whether observed gender differences are culturally-specific or represent broader developmental trends.

“We all tend to make a lot of assumptions about the development of gender roles, mostly through a Western lens,” said the paper’s first author Sheina Lew-Levy, who recently completed her PhD in Cambridge’s Department of Psychology. “However, very few studies have been done on gender roles in hunter-gatherer communities, whose organisation is distinct from other societies.”

̽��ֱ��two hunter-gatherer communities in the study, the Hadza of Tanzania and the BaYaka of Congo, typically live in mobile groups averaging 25-45 individuals and have multiple residences. Labour is generally divided along gender lines, with men responsible for animal products and women responsible for plant products, although they are relatively egalitarian.

Earlier studies of play in hunter-gatherer children have found that children overwhelmingly play in mixed-gender groups, which is less common in Western children over the age of three. ̽��ֱ��team in the current study, which included researchers from the ̽��ֱ�� of Nevada, Las Vegas, Washington State ̽��ֱ�� and Duke ̽��ֱ��, found that children in smaller hunter-gatherer camps were more likely to play in mixed-gender groups than those in larger camps, most likely due to a lack of playmates of the same gender.

Younger boys and girls spend similar amounts of time engaged in play, and they both spent times in games, exercise and object play. Typically, girls and boys engage in gender roles through play. In the BaYaka community, for example, fathers are highly involved in childcare. ̽��ֱ��researchers found that BaYaka children’s doll play reflected adult child caretaking, with no strong differences in BaYaka boys’ and girls’ play with dolls.

“Context explains many, although not all, gender differences in play,” said Lew-Levy. “We need a more inclusive understanding of child development, including children’s gendered play, across the world’s diverse societies.”

Reference:
Sheina Lew-Levy et al. ‘Gender-typed and gender-segregated play among Tanzanian Hadza and Congolese BaYaka hunter-gatherer children and adolescents.’ Child Development (2019). DOI: 10.1111/cdev.13306

̽��ֱ��gendered play of children from two hunter-gatherer societies is strongly influenced by the demographics of their communities and the gender roles modelled by the adults around them, a new study finds.

We all tend to make a lot of assumptions about the development of gender roles, mostly through a Western lens

Sheina Lew-Levy

Alyssa N. Crittenden

Hadza children engaged in cooking play

Yes

Farmers have less leisure time than hunter-gatherers, study suggests

ta385 — Tue, 21 May 2019 08:00:00 +0000

For two years, a team including ̽��ֱ�� of Cambridge anthropologist Dr Mark Dyble, lived with the Agta, a population of small scale hunter-gatherers from the northern Philippines who are increasingly engaging in agriculture.

Every day, at regular intervals between 6am and 6pm, the researchers recorded what their hosts were doing and by repeating this in ten different communities, they calculated how 359 people divided their time between leisure, childcare, domestic chores and out-of-camp work. While some Agta communities engage exclusively in hunting and gathering, others divide their time between foraging and rice farming.

̽��ֱ��study, published today in Nature Human Behaviour, reveals that increased engagement in farming and other non-foraging work resulted in the Agta working harder and losing leisure time. On average, the team estimate that Agta engaged primarily in farming work around 30 hours per week while foragers only do so for 20 hours. They found that this dramatic difference was largely due to women being drawn away from domestic activities to working in the fields. ̽��ֱ��study found that women living in the communities most involved in farming had half as much leisure time as those in communities which only foraged.

Dr Dyble, first author of the study, says: “For a long time, the transition from foraging to farming was assumed to represent progress, allowing people to escape an arduous and precarious way of life. But as soon as anthropologists started working with hunter-gatherers they began questioning this narrative, finding that foragers actually enjoy quite a lot of leisure time. Our data provides some of the clearest support for this idea yet.”

̽��ֱ��study found that on average, Agta adults spent around 24 hours each week engaged in out-of-camp work, around 20 hours each week doing domestic chores and around 30 hours of daylight leisure time. But the researchers found that time allocation differed significantly between adults.

For both men and women leisure time was lowest at around 30 years of age, steadily increasing in later life. There was also a sexual division of labour with women spending less time working out-of-camp, and more time engaged in domestic chores and childcare than men, even though men and women had a similar amount of leisure time. However, the study found that the adoption of farming had a disproportionate impact on women’s lives.

Dr Dyble says “This might be because agricultural work is more easily shared between the sexes than hunting or fishing. Or there may be other reasons why men aren’t prepared or able to spend more time working out-of-camp. This needs further examination.”

Agriculture emerged independently in multiple locations world-wide around 12,500 years ago, and had replaced hunting and gathering as the dominant mode of human subsistence around 5,000 years ago.

Co-author, Dr Abigail Page, an anthropologist at the London School of Hygiene and Tropical Medicine, adds: “We have to be really cautious when extrapolating from contemporary hunter-gatherers to different societies in pre-history. But if the first farmers really did work harder than foragers then this begs an important question – why did humans adopt agriculture?”

Previous studies, including one on the Agta, have variously linked the adoption of farming to increases in fertility, population growth and productivity, as well as the emergence of increasingly hierarchical political structures.

But Page says: “ ̽��ֱ��amount of leisure time that Agta enjoy is testament to the effectiveness of the hunter-gatherer way of life. This leisure time also helps to explain how these communities manage to share so many skills and so much knowledge within lifetimes and across generations.”

Reference:

Dyble, M., Thorley, J., Page, A.E., Smith, D. & Migliano, A.B. ‘Engagement in agricultural work is associated with reduced leisure time among Agta hunter-gatherers.’ Nature Human Behaviour (2019). DOI: 10.1038/s41562-019-0614-6

Hunter-gatherers in the Philippines who convert to farming work around ten hours a week longer than their forager neighbours, a new study suggests, complicating the idea that agriculture represents progress. ̽��ֱ��research also shows that the adoption of agriculture impacts most on the lives of women.

For a long time, the transition from foraging to farming was assumed to represent progress

Mark Dyble

Agta family relaxing in the late afternoon

Acknowledgements

This project was funded by Levehulme Trust grant RP2011-R-045.

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Opinion: No giant leap for mankind: why we’ve been looking at human evolution in the wrong way

Anonymous — Tue, 14 Jun 2016 13:21:45 +0000

Understanding exactly how and why humans evolved is clearly one of the most important goals in science. But despite a significant amount of research to date, these questions have remained a bit of a mystery. Of course, there is no shortage of theories – it has even been suggested that humans are just visiting aliens. However, most of the credible models tend to take something that is unique to humans – such as language – and show how all the other bits of being human derive from that.

But focusing on one dramatic change as an evolutionary driver in this way may not be the best approach to understanding our past. ̽��ֱ��question was discussed in a series of papers in Philosophical Transactions of the Royal Society B.

Hunting is a good example, as it is often used to explain human evolution. We eat far more meat than other primates – most of them are in fact entirely vegetarian. It has therefore been argued that meat was the high quality resource that allowed humans to evolve large and complex brains.

What’s more, it takes communication, cooperation and technology (those stone tools came in handy) to acquire it, so hunting could also explain a number of other typically human traits. Eating large animals also could also taught humans to share, leading to social cohesion and interdependence. Hunting is just one of many models that have been proposed to explain human uniqueness and cultural complexity – language, fire, cooking and grandmothers, who enhanced human success by investing in their daughters children instead of having more themselves.

Vince Smith/Flickr, CC BY-SA

̽��ֱ��problem with these theories is that they depend on evolution being a sort of one-step game, where one change produces a great leap forward, one from which other changes cascade. But the record does not support this. We split from our last common ancestor with the chimpanzees 5-6m years ago. But when we look at human ancestors between then and now, we do not find a single moment of dramatic change. Instead, it was cumulative – some 4m years ago we started walking upright on two legs, and about a million years later we started using stone tools. ̽��ֱ��size of our brains only started enlarging about 2m years ago.

Certainly there were periods that involved a more dynamic series of changes than others. For example, there was one at the beginning based on how hominins moved across the landscape, becoming bipedal and ranging over larger areas. Then about 2-3m years ago, there was another period of changes when brain size started to increase and childhood and adolescence periods started getting longer. This was coupled with boosts in technology and resource acquisition, such as hunting and gathering.

A final such period occurred in the last half million years, when cognitive changes associated with language, cooperation and cumulative culture – such as the development of more complex and composite technology, and the use of material culture for symbolic purposes – came to the fore. But even these periods, each lasting hundreds of thousands of years, were multi-event processes.

̽��ֱ��big picture

As far as we can tell, human evolution is like a mosaic of change, made up of many small steps, each of which adds a piece to what it is to be human. Only at the end do we see the full configuration, but had we stopped the clock at any point along that continuum, we would have seen a different mosaic. Human evolution is not one great transition, therefore, but many smaller ones.

Part of the problem in trying to see the big pattern of human evolution is that we look at it through the lens of the present – how we are today is the guide to how we were in the past. But the past was different in so many ways, and our extinct relatives show some surprising departures from what we expect when we base those expectations on ourselves.

̽��ֱ��remains of a Neanderthal wikimedia, CC BY-SA

Take body size. In the developed world, we are big, and sadly getting bigger in unhealthy ways. Better nutrition has led to increased body mass in many populations across the world. We also associate being large with being human, as it was thought that our ultimate ancestors, the australopithecines (living in Africa between about 4m and 2m years ago) were small, and that our own genus, Homo, marked a substantial increase in body size.

But that may not have been the case. In fact, nearly all the early, extinct species and subspecies of Homo were small, if not very small. ̽��ֱ��global average human body weight (combined sexes) now is over 60kg. No fossil hominin until the Neanderthals and modern humans reached an average of 50 kg, and most were below 40 kg – half the size of the average American male. Pygmy populations in Africa and Asia also weigh about 40kg, which means that most early and extinct hominins were pygmy sized. There are many advantages to large body size – such as resisting predators, access to larger prey – and the fact that our earliest ancestors did not become large tells us a lot about the energetic constraints under which they lived and reproduced.

We may picture our ancestors as rugged versions of ourselves, tall and strong, but they were not. We need to start thinking of them as creatures that were as unique as ourselves, but in different ways.

Understanding more about human evolution will depend on finding more fossils and applying more and more powerful scientific techniques. Ancient DNA, for example, is revealing extraordinary new details about our recent past. As important, however, will be using our greater knowledge of the overall pattern of human evolution, its tempo and mode, to inform us about the cumulative processes by which we became human, rather than expecting that with one great evolutionary bound, our hero was free.

Robert Foley, Professor of Human Evolution, ̽��ֱ�� of Cambridge

This article was originally published on ̽��ֱ��Conversation. Read the original article.

̽��ֱ��opinions expressed in this article are those of the individual author(s) and do not represent the views of the ̽��ֱ�� of Cambridge.

Robert Foley (Department of Archaeology and Anthropology) discusses the cumulative processes by which we became human.

Wikimedia Commons

Australopithecus afarensis reconstruction

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

For image use please see separate credits above.

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Let’s go wild: how ancient communities resisted new farming practices

amb206 — Wed, 06 Jan 2016 11:01:15 +0000

A box of seemingly unremarkable stones sits in the corner of Dr Giulio Lucarini’s office at the McDonald Institute for Archaeological Research where it competes for space with piles of academic journals, microscopes and cartons of equipment used for excavations. These palm-sized pebbles were used as grinding tools by people living in North Africa around 7,000 years ago. Tiny specks of plant matter recently found on their surfaces shine light on a fascinating period of human development and confirm theories that the transition between nomadic and settled lifestyles was gradual.

̽��ֱ��artefacts in Lucarini’s office come from a collection held in the store of the Museum of Archaeology and Anthropology (MAA) just a couple of minutes’ walk away. In the 1950s the well-known Cambridge archaeologist Sir Charles McBurney undertook an excavation of a cave called Haua Fteah located in northern Libya. He showed that its stratigraphy (layers of sediment) is evidence of continuous human habitation from at least 80,000 years ago right up to the present day. Finds from McBurney’s excavation were deposited at MAA.

In 2007, Professor Graeme Barker, also from Cambridge, started to re-excavate Haua Fteah with support from the ERC-funded TRANS-NAP Project. Until 2014, Barker and his team had the chance to spend more than one month each year excavating the site and surveying the surrounding Jebel Akhdar region, in order to investigate the relationships between cultural and environmental change in North Africa over the past 200,000 years.

Now an analysis of stone grinders from the Neolithic layers of Haua Fteah (dating from 8,000-5,500 years ago), carried out by Lucarini as his Marie Skłodowska-Curie Project ‘AGRINA’, in collaboration with Anita Radini ( ̽��ֱ�� of York) and Huw Barton ( ̽��ֱ�� of Leicester), yields new evidence about people living at a time seen as a turning point in human exploitation of the environment, paving the way for rapid expansion in population.

Around 11,000 years ago, during the early phase of the geological period known as Holocene, nomadic communities of Near Eastern regions made the transition from a hunter-gatherer lifestyle to a more settled farming existence as they began to exploit domesticated crops and animals developed locally. ̽��ֱ��research Lucarini is carrying out in Northern Libya and Western Egypt is increasingly revealing a contrasting scenario for the North African regions.

In a paper published today, Lucarini and colleagues explain that the surfaces of the grinders show plant use-wear and contain tiny residues of wild plants that date from a time when, in all likelihood, domesticated grains would have been available to them. These data are consistent with other evidence from the site, notably those from the analysis of the plant macro-remains carried out by Jacob Morales ( ̽��ֱ�� of the Basque Country), which confirmed the presence of wild plants alone in the site during the Neolithic. Together, this evidence suggests that domesticated varieties of grain were adopted late, spasmodically, and not before classical times, by people who lived in tune with their surroundings as they moved seasonally between naturally-available resources.

Lucarini is an expert in the study of stone tools and has a particular interest in the beginning of food production economies in North Africa. Using an integrated approach of low and high-power microscopy in the George Pitt-Rivers Lab at the McDonald Institute, and in the BioArCh Lab at the ̽��ֱ�� of York, he and his colleagues were able to spot plant residues, too small to be visible to the naked eye, caught in the pitted surface of several of the stones from Haua Fteah. Some of the grinders themselves exhibit clear ‘use-wear’ with their surfaces carrying the characteristic polish of having been used for grinding over long periods.

“It was thrilling to discover that microscopic traces of the plants ground by these stones have survived for so long, especially now that we’re able to use powerful high-power microscopes to look at the distinctive shape of the starch granules that offer us valuable clues to the identities of the plant varieties they come from,” says Lucarini.

By comparing the characteristic shape and size of the starch found in the grinders’ crevices to those in a reference collection of wild and domestic plant varieties collected in different North African and Southern European countries, Lucarini and Radini were able to determine that the residues most probably came from one of the species belonging to the Cenchrinae grasses. Various species of the genus Cenchrus are still gathered today by several African groups when other resources are scarce. Cenchrus is prickly and its seed is laborious to extract. But it is highly nutritious and, especially in times of severe food shortage, a highly valuable resource.

“Haua Fteah is only a kilometre from the Mediterranean and close to well-established coastal routes, giving communities there access to commodities such as domesticated grain, or at least the possibility to cultivate them. Yet it seems that people living in the Jebel Akhdar region may well have made a strategic and deliberate choice not to adopt the new farming practices available to them, despite the promise of higher yields but, instead, to integrate them into their existing practices,” says Lucarini.

“It’s interesting that today, even in relatively affluent European countries, the use of wild plants is becoming more commonplace, complementing the trend to use organically farmed food. Not only do wild plants contribute to a healthier diet, but they also more sustainable for the environment.”

Lucarini suggests that North African communities delayed their move to domesticated grains because it suited their highly mobile style of life. “Opting to exploit wild crops was a successful and low-risk strategy not to rely too heavily on a single resource, which might fail. It’s an example of the English idiom of not putting all your eggs in one basket. Rather than being ‘backward’ in their thinking, these nomadic people were highly sophisticated in their pragmatism and deep understanding of plants, animals and climatic conditions,” he says.

Evidence of the processing of wild plants at Haua Fteah challenges the notion that there was a sharp and final divide between nomadic lifestyles and more settled farming practices – and confirms recent theories that the adoption of domesticated species in North Africa was an addition to, rather than a replacement of, the exploitation of wild resources such as the native grasses that still grow wild at the site.

“Archaeologists talk about a ‘Neolithic package’ – made up of domestic plants and animals, tools and techniques – that transformed lifestyles. Our research suggests that what happened at Haua Fteah was that people opted for a mixed bag of old and new. ̽��ֱ��gathering of wild plants as well as the keeping of domestic sheep and goats chime with continued exploitation of other wild resources – such as land and sea snails – which were available on a seasonal basis with levels depending on shifts in climatic conditions,” says Lucarini.

“People had an intimate relationship with the environment they were so closely tuned to and, of course, entirely dependent on. This knowledge may have made them wary of abandoning strategies that enabled them to balance their use of resources – in a multi-spectrum exploitation of the environment.”

Haua Fteah continues to pose puzzles for archaeologists. ̽��ֱ��process of grinding requires two surfaces – a hand-held upper grinding tool and a base grinding surface. Excavation has yielded no lower grinders which made have been as simple as shallow dish-shaped declivities in local rock surfaces. “Only a fraction of the extensive site has been excavated so it may be that lower grinders do exist but they simply haven’t been found yet,” says Lucarini.

̽��ֱ��uncertain political situation in Libya has resulted in the suspension of fieldwork in Haua Fteah, in particular the excavation of the Neolithic and classical layers of the cave. Lucarini hopes that a resolution to the current crisis will allow work to resume within the next few years. He says: “Haua Fteah, with its 100,000 years of history and continuous occupation by different peoples, is a symbol of how Libya can be hospitable and welcoming. We trust in this future for the country.”

Inset images: Giulio Lucarini analysing the artefacts at the microscope, George Pitt-Rivers Laboratory, McDonald Institute for Archaeological Research (Aude Gräzer Ohara); Upper grinder found in the Neolithic layers of the cave, with plant residues stuck inside a crevice (Giulio Lucarini); Anita Radini collecting plants and algae for reference collection in Fezzan, Libya (Muftah Haddad); Cenchrinae starch granules from the Haua Fteah archaeological tools (a-c) and modern starch granules of Cenchrus biflorus (d) scale 20 µm (Anita Radini); Cenchrus ciliaris L., Burkina Faso (Arne Erpenbach, African plants - A Photo Guide www.africanplants.senckenberg.de).

Analysis of grinding stones reveals that North African communities may have moved slowly and cautiously from hunter-gatherer lifestyles to more settled farming practices. Newly published research by Cambridge archaeologist Dr Giulio Lucarini suggests that a preference for wild crops was a strategic decision.

Rather than being ‘backward’ in their thinking, these nomadic people were highly sophisticated in their pragmatism and deep understanding of plants, animals and climatic conditions

Giulio Lucarini

Haua Fteah, Cyrenaica, Libya. ̽��ֱ��cave’s entrance.

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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Millet: the missing piece in the puzzle of prehistoric humans’ transition from hunter-gatherers to farmers

jeh98 — Mon, 14 Dec 2015 11:08:15 +0000

̽��ֱ��domestication of the small-seeded cereal millet in North China around 10,000 years ago created the perfect crop to bridge the gap between nomadic hunter-gathering and organised agriculture in Neolithic Eurasia, and may offer solutions to modern food security, according to new research.

Now a forgotten crop in the West, this hardy grain – familiar in the west today as birdseed – was ideal for ancient shepherds and herders, who carried it right across Eurasia, where it was mixed with crops such as wheat and barley. This gave rise to ‘multi-cropping’, which in turn sowed the seeds of complex urban societies, say archaeologists.

A team from the UK, USA and China has traced the spread of the domesticated grain from North China and Inner Mongolia into Europe through a “hilly corridor” along the foothills of Eurasia. Millet favours uphill locations, doesn’t require much water, and has a short growing season: it can be harvested 45 days after planting, compared with 100 days for rice, allowing a very mobile form of cultivation.

Nomadic tribes were able to combine growing crops of millet with hunting and foraging as they travelled across the continent between 2500 and 1600 BC. Millet was eventually mixed with other crops in emerging populations to create ‘multi-crop’ diversity, which extended growing seasons and provided our ancient ancestors with food security.

̽��ֱ��need to manage different crops in different locations, and the water resources required, depended upon elaborate social contracts and the rise of more settled, stratified communities and eventually complex ‘urban’ human societies.

Researchers say we need to learn from the earliest farmers when thinking about feeding today’s populations, and millet may have a role to play in protecting against modern crop failure and famine.

“Today millet is in decline and attracts relatively little scientific attention, but it was once among the most expansive cereals in geographical terms. We have been able to follow millet moving in deep history, from where it originated in China and spread across Europe and India,” said Professor Martin Jones from the ̽��ֱ�� of Cambridge’s Department of Archaeology and Anthropology, who is presenting the research findings today at the Shanghai Archaeological Forum.

“These findings have transformed our understanding of early agriculture and society. It has previously been assumed that early agriculture was focused in river valleys where there is plentiful access to water. However, millet remains show that the first agriculture was instead centred higher up on the foothills – allowing this first pathway for ‘exotic’ eastern grains to be carried west.”

̽��ֱ��researchers carried out radiocarbon dating and isotope analysis on charred millet grains recovered from archaeological sites across China and Inner Mongolia, as well as genetic analysis of modern millet varieties, to reveal the process of domestication that occurred over thousands of years in northern China and produced the ancestor of all broomcorn millet worldwide.

“We can see that millet in northern China was one of the earliest centres of crop domestication, occurring over the same timescale as rice domestication in south China and barley and wheat in west China,” explained Jones.

“Domestication is hugely significant in the development of early agriculture – humans select plants with seeds that don’t fall off naturally and can be harvested, so over several thousand years this creates plants that are dependent on farmers to reproduce,” he said.

“This also means that the genetic make-up of these crops changes in response to changes in their environment – in the case of millet, we can see that certain genes were ‘switched off’ as they were taken by farmers far from their place of origin.”

As the network of farmers, shepherds and herders crystallised across the Eurasian corridor, they shared crops and cultivation techniques with other farmers, and this, Jones explains, is where the crucial idea of ‘multi-cropping’ emerged.

“ ̽��ֱ��first pioneer farmers wanted to farm upstream in order to have more control over their water source and be less dependent on seasonal weather variations or potential neighbours upstream,” he said. “But when ‘exotic’ crops appear in addition to the staple crop of the region, then you start to get different crops growing in different areas and at different times of year. This is a huge advantage in terms of shoring up communities against possible crop failures and extending the growing season to produce more food or even surplus.

“However, it also introduces a more pressing need for cooperation, and the beginnings of a stratified society. With some people growing crops upstream and some farming downstream, you need a system of water management, and you can’t have water management and seasonal crop rotation without an elaborate social contract.”

Towards the end of the second and first millennia BC larger human settlements, underpinned by multi-crop agriculture, began to develop. ̽��ֱ��earliest examples of text, such as the Sumerian clay tablets from Mesopotamia, and oracle bones from China, allude to multi-crop agriculture and seasonal rotation.

But the significance of millet is not just in transforming our understanding of our prehistoric past. Jones believes that millet and other small-seeded crops may have an important role to play in ensuring future food security.

“ ̽��ֱ��focus for looking at food security today is on the high-yield crops, rice, maize and wheat, which fuel 50% of the human food chain. However, these are only three of 50 types of cereal, the majority of which are small-grained cereals or “millets”. It may be time to consider whether millets have a role to play in a diverse response to crop failure and famine,” said Jones.

“We need to understand more about millet and how it may be part of the solution to global food security – we may have a lot still to learn from our Neolithic predecessors.”

Inset images: Martin Jones with millet in North China (Martin Jones); Inner Mongolian millet farmer in Chifeng (Martin Jones).

New research shows a cereal familiar today as birdseed was carried across Eurasia by ancient shepherds and herders laying the foundation, in combination with the new crops they encountered, of ‘multi-crop’ agriculture and the rise of settled societies. Archaeologists say ‘forgotten’ millet has a role to play in modern crop diversity and today’s food security debate.

We have been able to follow millet moving in deep history, from where it originated in China and spread across Europe and India

Martin Jones

John Moore

Foxtail millet

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‘Fourth strand’ of European ancestry originated with hunter-gatherers isolated by Ice Age

fpjl2 — Mon, 16 Nov 2015 10:33:13 +0000

̽��ֱ��first sequencing of ancient genomes extracted from human remains that date back to the Late Upper Palaeolithic period over 13,000 years ago has revealed a previously unknown “fourth strand” of ancient European ancestry.

This new lineage stems from populations of hunter-gatherers that split from western hunter-gatherers shortly after the ‘out of Africa’ expansion some 45,000 years ago and went on to settle in the Caucasus region, where southern Russia meets Georgia today.

Here these hunter-gatherers largely remained for millennia, becoming increasingly isolated as the Ice Age culminated in the last ‘Glacial Maximum’ some 25,000 years ago, which they weathered in the relative shelter of the Caucasus mountains until eventual thawing allowed movement and brought them into contact with other populations, likely from further east.

This led to a genetic mixture that resulted in the Yamnaya culture: horse-borne Steppe herders that swept into Western Europe around 5,000 years ago, arguably heralding the start of the Bronze Age and bringing with them metallurgy and animal herding skills, along with the Caucasus hunter-gatherer strand of ancestral DNA – now present in almost all populations from the European continent.

̽��ֱ��research was conducted by an international team led by scientists from Cambridge ̽��ֱ��, Trinity College Dublin and ̽��ֱ�� College Dublin. ̽��ֱ��findings are published today in the journal Nature Communications.

“ ̽��ֱ��question of where the Yamnaya come from has been something of a mystery up to now,” said one of the lead senior authors Dr Andrea Manica, from Cambridge’s Department of Zoology.

“We can now answer that as we’ve found that their genetic make-up is a mix of Eastern European hunter-gatherers and a population from this pocket of Caucasus hunter-gatherers who weathered much of the last Ice Age in apparent isolation. This Caucasus pocket is the fourth major strand of ancient European ancestry, one that we were unaware of until now,” he said

Professor Daniel Bradley, leader of the Trinity team, said: “This is a major new piece in the human ancestry jigsaw, the influence of which is now present within almost all populations from the European continent and many beyond.”

Previously, ancient Eurasian genomes had revealed three ancestral populations that contributed to contemporary Europeans in varying degrees, says Manica.

Following the ‘out of Africa’ expansion, some hunter-gatherer populations migrated north-west, eventually colonising much of Europe from Spain to Hungary, while other populations settled around the eastern Mediterranean and Levant, where they would develop agriculture around 10,000 years ago. These early farmers then expanded into and colonised Europe.

Lastly, at the start of the Bronze Age around 5,000 years ago, there was a wave of migration from central Eurasia into Western Europe – the Yamnaya.

However, the sequencing of ancient DNA recovered from two separate burials in Western Georgia – one over 13,000 years old, the other almost 10,000 years old – has enabled scientists to reveal that the Yamnaya owed half their ancestry to previously unknown and genetically distinct hunter-gatherer sources: the fourth strand.

By reading the DNA, the researchers were able to show that the lineage of this fourth Caucasus hunter-gatherer strand diverged from the western hunter-gatherers just after the expansion of anatomically modern humans into Europe from Africa.

̽��ֱ��Caucasus hunter-gatherer genome showed a continued mixture with the ancestors of the early farmers in the Levant area, which Manica says makes sense given the relative proximity. This ends, however, around 25,000 years ago – just before the time of the last glacial maximum, or peak Ice Age.

At this point, Caucasus hunter-gatherer populations shrink as the genes homogenise, a sign of breeding between those with increasingly similar DNA. This doesn’t change for thousands of years as these populations remain in apparent isolation in the shelter of the mountains – possibly cut off from other major ancestral populations for as long as 15,000 years – until migrations began again as the Glacial Maximum recedes, and the Yamnaya culture ultimately emerges.

“We knew that the Yamnaya had this big genetic component that we couldn’t place, and we can now see it was this ancient lineage hiding in the Caucasus during the last Ice Age,” said Manica.

While the Caucasus hunter-gatherer ancestry would eventually be carried west by the Yamnaya, the researchers found it also had a significant influence further east. A similar population must have migrated into South Asia at some point, says Eppie Jones, a PhD student from Trinity College who is the first author of the paper.

“India is a complete mix of Asian and European genetic components. ̽��ֱ��Caucasus hunter-gatherer ancestry is the best match we’ve found for the European genetic component found right across modern Indian populations,” Jones said. Researchers say this strand of ancestry may have flowed into the region with the bringers of Indo-Aryan languages.

̽��ֱ��widespread nature of the Caucasus hunter-gatherer ancestry following its long isolation makes sense geographically, says Professor Ron Pinhasi, a lead senior author from ̽��ֱ�� College Dublin. “ ̽��ֱ��Caucasus region sits almost at a crossroads of the Eurasian landmass, with arguably the most sensible migration routes both west and east in the vicinity.”

He added: “ ̽��ֱ��sequencing of genomes from this key region will have a major impact on the fields of palaeogeneomics and human evolution in Eurasia, as it bridges a major geographic gap in our knowledge.”

David Lordkipanidze, Director of the Georgian National Museum and co-author of the paper, said: “This is the first sequence from Georgia – I am sure soon we will get more palaeogenetic information from our rich collections of fossils.”

Inset image: the view from the Satsurblia cave in Western Georgia, where a human right temporal bone dating from over 13,000 years ago was discovered. DNA extracted from this bone was used in the new research.

Reference:
E.R. Jones et. al. ‘Upper Palaeolithic genomes reveal deep roots of modern Eurasians.’ Nature Communications (2015). DOI: 10.1038/ncomms9912

Populations of hunter-gatherers weathered Ice Age in apparent isolation in Caucasus mountain region for millennia, later mixing with other ancestral populations, from which emerged the Yamnaya culture that would bring this Caucasus hunter-gatherer lineage to Western Europe.

This Caucasus pocket is the fourth major strand of ancient European ancestry, one that we were unaware of until now

Andrea Manica

Eppie Jones

DNA was extracted from the molar teeth of this skeleton, dating from almost 10,000 years ago and found in the Kotias Klde rockshelter in Western Georgia.

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Distance running may be an evolutionary ‘signal’ for desirable male genes

fpjl2 — Wed, 08 Apr 2015 18:05:25 +0000

Pre-birth exposure to high levels of the male sex hormone testosterone has already been shown to confer evolutionary advantages for men: strength of sex drive, sperm count, cardiovascular efficiency and spatial awareness, for example.

Now, latest research on marathon runners using finger length as a marker for hormone exposure shows that people who experienced higher testosterone in the womb are also better at distance running – a correlation particularly strong in men, although also present in women.

Researchers say the finding that males with greater “reproductive potential” from an evolutionary standpoint are better distance runners suggests females may have selected for such athletic endurance when mating during our hunter-gatherer past, perhaps because ‘persistence hunting’ – exhausting prey by tirelessly tracking it – was a vital way to get food.

Distance running may also have acted as a positive ‘signal’ for females of desirable male genetics more generally, say researchers: good runners were likely to be better persistence hunters and consequently better providers. This increases the likelihood they would have other key traits of good providers such as intelligence and generosity.

̽��ֱ��study was conducted by researchers at the ̽��ֱ�� of Cambridge’s Division of Biological Anthropology and is published today in the journal PLOS ONE.

“ ̽��ֱ��observation that endurance running ability is connected to reproductive potential in men suggests that women in our hunter-gatherer past were able to observe running as a signal for a good breeding partner,” said the study’s lead author Dr Danny Longman.

“It was thought that a better hunter would have got more meat, and had a healthier – and larger – family as a consequence of providing more meat for his family. But hunter-gatherers may have used egalitarian systems with equal meat distribution as we see in remaining tribes today. In which case more meat is not a factor, but the ability to get meat would signal underlying traits of athletic endurance, as well as intelligence – to track and outwit prey – and generosity – to contribute to tribal society. All traits you want passed on to your children,” he said.

Using the largest sample of marathon runners of any study of its kind, Longman and colleagues tested for specific finger lengths known as the 2D:4D digit ratio. Previous studies have showed that those exposed to more prenatal testosterone have a longer ring finger (4th digit) in comparison to their index finger (2nd digit).

This digit ratio is the most accurate known way to tell if an adult was exposed to higher levels of testosterone as a foetus – a proven predictor of the “potential for reproductive success” in men, say researchers.

̽��ֱ��team analysed 542 runners (439 men; 103 women) at the Robin Hood half marathon in Nottingham by photocopying hands and taking run times and other key details just after runners crossed the line.

They found that the 10% of men with the most masculine digit ratios were, on average, 24 minutes and 33 seconds faster than the 10% of men with the least masculine digit ratios.

̽��ֱ��correlation was also found in women, but was much more pronounced in men, suggesting a stronger evolutionary selection in men for running ability. ̽��ֱ��10% of women with the most masculine digit ratios were, on average, 11 minutes and 59 seconds faster than the 10% with the least masculine.

Longman points out that prenatal testosterone exposure is a very small influence on running ability that doesn’t compete with training and muscle strength when it comes to performance, but their unprecedentedly large sample size of over 500 people enabled the team to gather conclusive evidence.

“Humans are hopeless sprinters. Rabbits, for example, are much faster sprinters, despite being fat and round. But humans are fantastically efficient long-distance runners, comparable to wolves and wild coyotes,” said Longman.

“We sweat when most animals would overheat; our tendons and posture are designed to propel our next strides – there was likely a selective pressure for all these benefits during our evolution.”

Persistence hunting is thought to have been one of the earliest forms of human hunting, evolving approximately two million years ago, said Longman.

“You can still see examples of persistence hunting in parts of Africa and Mexico today. Hunters will deliberately choose the hottest time of day to hunt, and chase and track an antelope or gnu over 30 to 40 kilometres for four or five hours. ̽��ֱ��animal recovers less and less from its running until it collapses exhausted and is easy to kill,” Longman said.

“This may sound crazy, but when a hunter is relatively fit the amount of energy they expend is actually tiny compared to the energy benefits of an antelope-sized animal, for example. Before the domestication of dogs, persistence hunting may have been one of the most efficient forms of hunting, and as a consequence may have shaped human evolution.”

New research shows that males with higher ‘reproductive potential’ are better distance runners. This may have been used by females as a reliable signal of high male genetic quality during our hunter-gatherer past, as good runners are more likely to have other traits of good hunters and providers, such as intelligence and generosity.

Persistence hunting may have been one of the most efficient forms of hunting, and as a consequence may have shaped human evolution

Danny Longman

Warein

Running

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