Tag Archives: Darren Curnoe

We found evidence of early humans in the jungles of Borneo

The Conversation

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Digging in Traders Cave in the iconic Niah Caves archaeological complex. Darren Curnoe excavates while Roshan Peiris observes. (Photo: Mhd. S. Sauffi/Darren Curnoe) Author provided

Darren Curnoe, UNSW

I recently led a team excavating at one of the most iconic archaeological locations in Southeast Asia, Niah Caves in Malaysia.

Over a period of three weeks, we dug through what we believe to be around 20,000 years of human history. We uncovered several human bones, the remains of large mammals (probably deer and wild cattle) and marine oyster shells indicating a period of seafood meals. Stone tools and charred rocks were also unearthed.

It was exciting and a little bit daunting to be digging at Niah Caves, given its place in both the history of archaeology and more broadly of humankind.

Daily Dig Diary Day 21: ancient human bones, tools and oyster shells were found at various depths. All diary postings can be seen at https://www.facebook.com/curnoeanthropologist/.

Read more: Curious Kids: Where did the first person come from?


Famous for head hunters

Niah Caves National Park is located in the eastern part of Sarawak, a state of Malaysia that hugs the northern coastal strip of the island of Borneo.

Borneo straddles the equator, and is covered mostly by dense tropical rainforest. It’s home to a remarkable variety of wildlife, including the endangered orangutan.

Sarawak also has a rich cultural heritage with almost 40 indigenous linguistic or cultural groups living there. It is an island that was famous until the 1970s for its head hunters.

It’s also the place where Alfred Wallace, credited by history as the discoverer of evolution by means of natural selection, developed his ideas during the nineteenth century.


Read more: World’s scientists turn to Asia and Australia to rewrite human history


Sarawak also has an extraordinary history of human occupation. This stretches back at least 46,000 years ago, soon after the earliest modern humans settled the region after they made their long journey out of Africa.

Borneo is the island where these early people began island hopping across Southeast Asia and eventually settling New Guinea and Australia, making it crucial also to understanding ancient human history across the Australasian region.

Incredible caves

The massive Niah Caves complex sits within a large limestone hill in the centre of the national park. There are 21 caves in the main cave network with six large entrances or cave mouths. The largest cave is the West Mouth (Lobang Kualar) which is more than 60 metres high in parts.

The chambers of Niah Caves reverberate with the sounds of bats and birds known as swiftlets, which seem to fill almost every nook and cranny they have to offer. The swiftlets make highly sought after bird nests, used for traditional Chinese medicine and to make bird’s nest soup. These nests are collected and traded each day by local Punan men, who scale tens of metres into the highest ceilings of the cave climbing wooden poles without safety harnesses, risking their lives in the process.

Daily Dig Diary Day 16: bamboo structures allow local men to collect birds nests from the caves. All diary postings can be seen at https://www.facebook.com/curnoeanthropologist/.

The potential of Niah Caves for informing scientific understanding of human origins was first recognised during the nineteenth century, when Wallace alerted Thomas Henry Huxley – “Darwin’s bulldog” – to them. Huxley organised the first European expedition to Niah Caves, led by Alfred Hart Everett in 1878-79, but he returned to England with little to show for his efforts.

The caves had to wait almost 100 years before the first archaeological digs were done, led by Tom Harrisson from 1954, and joined soon after by his partner Barbara Harrisson. Their excavations ran for 13 years until 1967, digging in several of the caves in the Niah Caves complex and adjacent areas.

Their largest haul was found in the West Mouth, where in 1958 they unearthed the so-called “Deep Skull”. This was a partial skull, and accompanying leg bones from an individual today known to be about 35,000 years old.

The Harrissons found a total of 270 sets of human skeletons in the West Mouth, but unlike Deep Skull most of them are from an early farming or Neolithic cemetery, dated between about 2,000 and 4,000 years old.

Daily Dig Diary Day 20: cremated bones in a Neolithic cemetery. All diary postings can be seen at https://www.facebook.com/curnoeanthropologist/.

Cemeteries and coffin boats

Three other teams of archaeologists have worked at Niah Caves since the Harrisons.

The first was from Malaysia, and dug in the West Mouth in the 1970s – the scientists found an Iron Age cemetery, dating between about 500 and 2,000 years old.

The second group, also from Malaysia, excavated a small area of an adjacent cave called Painted Cave and found yet more Iron Age cemeteries. This cave had also been dug earlier by the Harrissons, where they found numerous boat-shaped coffins and described dozens of paintings adorning the walls of the cave.

Daily Dig Diary Day 12: boat coffins in Painted Cave. All diary postings can be seen at https://www.facebook.com/curnoeanthropologist/.

The final team was from Cambridge University and focused on reassessing the earlier work of the Harrissons. Among other things they provided a detailed framework for determining the age of the archaeological finds of the Harrissons using modern geological techniques.

After six years of planning the project with colleagues at the Sarawak Museum Department, on the twentieth of November 2017 we began the next phase of archaeological research at Niah Caves. It was the fiftieth anniversary of the end of the Harrisson’s excavations, and also the year of my fiftieth birthday.

Traders Cave

We chose to dig at a site called Traders cave, which sits outside of the Great Cave complex. We had surveyed it numerous times and had always been struck by its potential.

Traders Cave is 190 metres long, about 30 metres wide and up to 15 metres high. The Harrissons dug a small pit at the entrance to it back in 1956 but found nothing of note and gave up, focusing instead on the West Mouth.

My team included people from from Australia, Malaysia and Sri Lanka, involving archaeologists, heritage specialists and student volunteers.

The team included Australians, Malaysians and Sri Lankans. Darren Curnoe, Author provided

Across the three weeks, we dug two squares in the middle of the cave, about 20 metres apart. Each one measured one metre by one metre, and we dug each layer in small units or “spits” of five centimetres.

In the first one we dug through two metres of sediment before we stopped, to continue the work next year. In the second square, we reached a depth of 1.8 metres before we hit the limestone floor of the cave and could dig no further.

Darren Curnoe digging Square A in Traders Cave. Mhd. S. Sauffi/Darren Curnoe

So, what did we find? In the first square, we found several human bones including fragments of skulls and part of a leg bone, across different layers. We also recovered the remains of large mammals, probably deer and wild cattle, and a whole layer of large marine oyster shells that were brought into the cave by people and probably consumed there. A number of stone tools and rocks that seemed to have been burned in fires made in the cave were also unearthed.

Daily Dig Diary Day 8: sorting through the findings from one of the pits. All diary postings can be seen at https://www.facebook.com/curnoeanthropologist/..

The second square was not nearly as rich but it did provide us with a collection of stone tools stretching across much of its nearly two metre depth.

At the moment, all of the evidence we have points to us having dug through Palaeolithic layers. Based on comparisons with the objects found by the Harrissons in the Great Cave complex, we think the Traders Cave deposits are mostly 20,000 years old or more.

Next year we’ll return to dig again for at least two weeks. We plan to focus on the first square, the richest one: we’ll dig until we reach the cave floor, and also open the square up, enlarging it to search for more human and animal bones and stone tools.

The ConversationA major focus of our work will also be to determine the age of the finds and the sediments at Traders Cave, using as many different techniques as we can so we can be confident of their true age.

Darren Curnoe, Associate Professor and Chief Investigator, ARC Centre of Excellence for Australian Biodiversity and Heritage, University of New South Wales, UNSW

This article was originally published on The Conversation. (Reblogged by permission). Read the original article.

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Was agriculture the greatest blunder in human history?

The Conversation

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Rice farmers near Siem Reap, Cambodia. Darren Curnoe, Author provided

Darren Curnoe, UNSW

Twelve thousand years ago everybody lived as hunters and gatherers. But by 5,000 years ago most people lived as farmers.

This brief period marked the biggest shift ever in human history with unparalleled changes in diet, culture and technology, as well as social, economic and political organisation, and even the patterns of disease people suffered.

While there were upsides and downsides to the invention of agriculture, was it the greatest blunder in human history? Three decades ago Jarred Diamond thought so, but was he right?

Agriculture developed worldwide within a single and narrow window of time: between about 12,000 and 5,000 years ago. But as it happens it wasn’t invented just once but actually originated at least seven times, and perhaps 11 times, and quite independently, as far as we know.

Farming was invented in places like the Fertile Crescent of the Middle East, the Yangzi and Yellow River Basins of China, the New Guinea highlands, in the Eastern USA, Central Mexico and South America, and in sub-Saharan Africa.

And while its impacts were tremendous for people living in places like the Middle East or China, its impacts would have been very different for the early farmers of New Guinea.

The reasons why people took up farming in the first place remain elusive, but dramatic changes in the planet’s climate during the last Ice Age — from around 20,000 years ago until 11,600 years ago — seem to have played a major role in its beginnings.

The invention of agriculture thousands of years ago led to the domestication of today’s major food crops like wheat, rice, barley, millet and maize, legumes like lentils and beans, sweet potato and taro, and animals like sheep, cattle, goats, pigs, alpacas and chickens.

It also dramatically increased the human carrying capacity of the planet. But in the process the environment was dramatically transformed. What started as modest clearings gave way to fields, with forests felled and vast tracts of land turned over to growing crops and raising animals.

In most places the health of early farmers was much poorer than their hunter-gatherer ancestors because of the narrower range of foods they consumed alongside of widespread dietary deficiencies.

At archaeological sites like Abu Hereyra in Syria, for example, the changes in diet accompanying the move away from hunting and gathering are clearly recorded. The diet of Abu Hereyra’s occupants dropped from more than 150 wild plants consumed as hunter-gatherers to just a handful of crops as farmers.

In the Americas, where maize was domesticated and heavily relied upon as a staple crop, iron absorption was consequently low and dramatically increased the incidence of anaemia. While a rice based diet, the main staple of early farmers in southern China, was deficient in protein and inhibited vitamin A absorption.

There was a sudden increase in the number of human settlements signalling a marked shift in population. While maternal and infant mortality increased, female fertility rose with farming, the fuel in the engine of population growth.

The planet had supported roughly 8 million people when we were only hunter-gatherers. But the population exploded with the invention of agriculture climbing to 100 million people by 5,000 years ago, and reaching 7 billion people today.

People began to build settlements covering more than ten hectares – the size of ten rugby fields – which were permanently occupied. Early towns housed up to ten thousand people within rectangular stone houses with doors on their roofs at archaeological sites like Çatalhöyük in Turkey.

By way of comparison, traditional hunting and gathering communities were small, perhaps up to 50 or 60 people.

Crowded conditions in these new settlements, human waste, animal handling and pest species attracted to them led to increased illness and the rapid spread of infectious disease.

Today, around 75% of infectious diseases suffered by humans are zoonoses, ones obtained from or more often shared with domestic animals. Some common examples include influenza, the common cold, various parasites like tapeworms and highly infectious diseases that decimated millions of people in the past such as bubonic plague, tuberculosis, typhoid and measles.

In response, natural selection dramatically sculpted the genome of these early farmers. The genes for immunity are over-represented in terms of the evidence for natural selection and most of the changes can be timed to the adoption of farming. And geneticists suggest that 85% of the disease-causing gene variants among contemporary populations arose alongside the rise and spread of agriculture.

In the past, humans could only tolerate lactose during childhood, but with the domestication of dairy cows natural selection provided northern European farmers and pastoralist populations in Africa and West Asia the lactase gene. It’s almost completely absent elsewhere in the world and it allowed adults to tolerate lactose for the first time.

Starch consumption is also feature of agricultural societies and some hunter-gatherers living in arid environments. The amylase genes, which increase people’s ability to digest starch in their diet, were also subject to strong natural selection and increased dramatically in number with the advent of farming.

Another surprising change seen in the skeletons of early farmers is a smaller skull especially the bones of the face. Palaeolithic hunter-gatherers had larger skulls due to their more mobile and active lifestyle including a diet which required much more chewing.

Smaller faces affected oral health because human teeth didn’t reduce proportionately to the smaller jaw, so dental crowding ensued. This led to increased dental disease along with extra cavities from a starchy diet.

Living in densely populated villages and towns created for the first time in human history private living spaces where people no longer shared their food or possessions with their community.

These changes dramatically shaped people’s attitudes to material goods and wealth. Prestige items became highly sought after as hallmarks of power. And with larger populations came growing social and economic complexity and inequality and, naturally, increasing warfare.

Inequalities of wealth and status cemented the rise of hierarchical societies — first chiefdoms then hereditary lineages which ruled over the rapidly growing human settlements.

Eventually they expanded to form large cities, and then empires, with vast areas of land taken by force with armies under the control of emperors or kings and queens.

This inherited power was the foundation of the ‘great’ civilisations that developed across the ancient world and into the modern era with its colonial legacies that are still very much with us today.

The ConversationNo doubt the bad well and truly outweighs all the good that came from the invention of farming all those millenia ago. Jarred Diamond was right, the invention of agriculture was without doubt the biggest blunder in human history. But we’re stuck with it, and with so many mouths to feed today we have to make it work better than ever. For the future of humankind and the planet.

Darren Curnoe, Associate Professor and Chief Investigator, ARC Centre of Excellence for Australian Biodiversity and Heritage, University of New South Wales, UNSW

This article was originally published on The Conversation. (Reblogged by permission). Read the original article.

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Our ancestors were carnivorous super-predators, so do we really have a choice about eating meat?

The Conversation

Darren Curnoe, UNSW Australia

The internet abounds with ‘expert advice’ on what we should or shouldn’t eat. High carb or low carb diets? Grains or gluten free eating? Meat eating or veganism?

Most of it promotes our food choices as a simple binary decision – eat this don’t eat that; this is good for you, that’s bad.

Yet, the decisions we make about what to eat are a complicated affair. They’re never a simple case of eat what’s best for your health or what naturally suits our physiology.

Cultural mores, religious practices, ethical concerns, gender, stage of life and state of health, geographic location, economics and family and individual preferences all play a role in the selections we make.

One of the most confusing choices people face is whether to eat meat or not, and opinions are very strong on both sides of the debate. But is it natural to do so?

Our ancestors evolved to be super-predators with meat eating and sharing a key survival strategy for our kind for millions of years. So, do we really have a choice to eat meat today?

Things to eat and avoid

Culture is a ubiquitous force when it comes to making choices about food. All human societies, from hunter-gatherer to post-industrial ones like our own, have food preferences and fads, or restrictions and taboos.

We eat things because they taste good, even if they are bad for us. Other things we avoid have proven health benefits, but maybe they’re simply not as tasty or palatable.

Sometimes food taboos exist for good reason – such as to prevent overuse of an important resource or to reduce the risk of food poisoning at an important stage of life.

But just as often we find dietary preferences are culturally patterned behaviours, such as women changing their diet at varying times in their menstrual cycle, despite the practice having negative health consequences.

On top of this, certain nutrients like sugar activate reward pathways in the brain similar to those associated with cocaine use, making them highly sought after, and potentially addictive.

Much of the dietary advice found on the internet might be well meaning, but a substantial amount of it is misleading and frequently smacks of anti-intellectualism.

Bowls full of bullshit

More often than not though the ease with which we can post our opinions online has led to a glut of dietary advice that can only be described as ‘bullshit’.

Bullshit is defined by Princeton philosopher Harry Frankfurt to mean something espoused by someone who pretends to know a lot about it but actually knows very little.

It’s rife on the internet and fuels both anti-intellectualism and a deep mistrust of scientific authority.

The debate about meat, and whether we humans have evolved to eat it, has to be one of the best examples of bullshit seen on the web.

It has largely lost all sense of the complex reality of food choice behaviours, and far too often tries to rewrite our evolutionary history by invoking pseudoscience.

Some pro-vegetarian or vegan promoting websites mistakenly claim that humans shouldn’t eat meat because we evolved to be herbivores.

The substance of their arguments is often traceable back to the influential but pseudoscientific views of vegan physician Milton R. Mills.

Some vegan sites even claim support from anthropology for their anti-meat agenda.

We also find bogus arguments like these promoted in the mainstream media where some columnists push an anti-intellectual agenda by misrepresenting the views of scientists themselves such as fellow anthropologist Richard Leakey.

For the record, here’s what he has actually written about meat eating and human evolution.

But if you love a good steak, don’t take the moral high ground just yet. There’s plenty of bullshit in the pro-meat camp as well.

One need only read internet debates on the subject of meat eating to see barnyards full of it on both sides.

As an interesting aside, social anthropologists have found meat to be the one food that’s subject to food taboos across a large number of cultures.

So, there might be a much deeper (genetic?) origin to our varying opinions towards meat, with some people loving it, and others repulsed by it, across the world.

Humans evolved as super-predators

No matter what the most militant of vegans or vegetarians would like to think, there’s an abundance of scientific evidence that we humans evolved to be predator apes.

Our ancestors were highly skilled hunters and meat was widely eaten and highly prized.

While hunter-gatherers varied considerably in terms of how much meat they consumed, none of them was vegan, and such diets simply wouldn’t have been available or viable options for them anyway.

Our human ecological and life history strategy evolved around acquiring and sharing hard to catch, but large pay-off, foods such as big mammals and fish.

We humans rely on culture for everything we do, whether it be the values and shared ideas we have about the world, social relationships, or the methods and tools we use to aid with the catching and processing food.

The earliest examples of stone tools used for acquiring and processing food have been found in Africa and date to around 3.3 million years old.

Butchered and defleshed bones from around the same time indicate clearly that early humans were butchering large bodied mammals for food.

Fire was probably used in an at least an ad hoc way from around 1.6 million years ago – probably much earlier – but became a regular tool for pre-modern humans from at least 400,000 years ago.

Cooking played a major role in making both meat and starchy foods palatable and digestible, providing our ancestors with a huge survival advantage.

Food cooking, especially of meat, may even have contributed to the evolution of our large brains.

Endurance running, persistence hunting

Humans are the only living primate adapted for running – particularly endurance running, and during the hottest time of the day. This seems also to be a universal pattern among the species belonging to the human genus Homo; all dozen or more of us.

The organs of balance – our vestibular system – are designed to help keep the head stable because of its tendency to pitch forward when running.

Humans possess a nuchal ligament to connect the base of the skull to the spinal column and help keep the head balanced as we run.

We have long lower limbs and a narrow trunk and pelvis. Our rib-cage is barrel shaped rather than shaped like a funnel with a bulging gut, like chimpanzees.

The muscles of our shoulder are decoupled from those of our neck because they aren’t used for climbing, aiding the need to counterbalance the legs and reduce rotation of the head when running.

Many of our lower limb muscles and their tendons – like the gluteus maximus, iliotibial tract and Achilles tendon– are also adapted for running.

We have large ankle bones, arches across two directions of the foot, and the ligaments of the foot absorb energy when we run releasing it during toe-off.

Our big toe has been brought into line with the other toes, losing its branch grasping abilities.

Humans have sparse and short body hair and between 5 and 12 million appocrine sweat glands that can produce up to 12 litres of water a day to help prevent hyperthermia.

The only other African mammals that are active during the heat of the day, running long distances, are dogs and hyenas.

Our species also has uniformly pigmented skin – the exception being people living at high latitude who probably lost their skin colour very recently.

Pigmentation protects the outer layers of the skin against sun damage and ultimately skin cancer, so is vital for a mammal that has sparse body hair and is active in the heat of the day.

All of this points to hunting, and a particular style called the persistence hunt. It would have been widespread prior to the invention of weapons like bows and arrows around 60,000 years ago.

David Attenborough’s Life of Mammals series has some wonderfully engaging footage of San men undertaking a persistence hunt. It’s well worth a look.

A gutsy move

To claim we shouldn’t eat meat because we aren’t anatomically identical to carnivores demonstrates a profound misunderstanding of how evolution has worked.

Humans and carnivores, like dogs and hyenas, are very different kinds of mammals, separated by around 100 million years of evolutionary history.

We are primates, and our basic body plan is constrained genetically by our primate heritage. You can’t turn an ape into a wolf in just 3 million years!

While much has been made of our sacculated colon, this is a feature common to all apes, and is the result of common evolutionary inheritance.

We have all evolved from plant eating apes regardless of what we eat today. A sacculated colon in no way suggests we are herbivores.

Besides, humans do eat a lot more than just meat and clearly require a wide range of foods for a balanced diet. For example, no apes can synthesise vitamin C in their bodies so it must be acquired from plant food sources.

However, the human gut differs substantially from other apes in a couple of key respects: first, we have a small total gut for our body size, and second, our greatest gut volume lies in the small intestine, while in other apes it lies in the colon.

A bigger small intestine indicates we absorb most of our nutrients there, and that we obtain them from high quality, nutrient dense, sources like meat and starchy foods.

While a large colon, as seen in all other apes, fits with their strongly plant based diet (87-99% of foods) and the need to ferment it. Humans simply can’t survive on the type of diet we see chimpanzees, gorillas, orangutans or gibbons eating.

Another disturbing piece of evidence worth noting is tapeworms. Each year millions of people around the world are infected with them through eating under-cooked or raw meat.

And here’s the rub: without infecting a human host, at least four species of tapeworm would be unable to reproduce. Humans are a definitive host for them.

The only other mammals to be definitive hosts for tapeworms are carnivores like lions and hyenas.

Molecular clocks suggest human tapeworms evolved about the time our ancestors began to hunt.

Briefly, two other human features need mentioning because they have been widely used to mislead people on the issue of meat eating.

Our teeth are very similar to those of other apes in terms of the size, shape and number we posses – all apes and Old World monkeys have 32.

But there’s one important difference: we humans have small canine teeth.

The canine teeth of apes are not used for catching prey or chewing food. Instead they are for display and are used by males to battle it out for dominance in a social hierarchy or for access to mates.

A small canine tooth evolved in human evolution sometime after 5 million years ago and represents a shift in the social structure and mating behaviour of our ancestors.

It shows us that male-to-male conflict had reduced. Perhaps because males were sharing food with females and each other. Males and females may even have been monogamous at this time.

Lastly, humans have nails instead of claws because we are primates. No primates have claws. So to claim that our lack of claws shows we shouldn’t eat meat again indicates a clear lack of familiarity with our biology.

Besides, early human hunters used tools, their big brains and understanding of their environment and cooperative tendencies to catch food, not their brawn.

Making informed choices

There is a danger in taking our evolutionary history as fate. We are no longer hunter-gatherers and our lifestyle is about as far removed from that of our ancestors as can be imagined.

We need to adapt to our changing circumstances and find a diet that healthily supports it, like we have always done as a species.

Whether we choose to eat meat or not is not just a question of biology. It involves a complex set of cultural, social, ethical, health, personal and economic factors as well. It is not binary.

The best guide for most people on how to eat comes from science itself, for example, as presented in guidelines like those from the Australian Government.

But many millions of people today survive on low or no meat diets, by choice, or otherwise. In this sense, vegetarianism or veganism is like any other culturally situated dietary choice.

It should be both understood and respected as such and can’t be explained away or justified by appealing to a particular narrative of our evolutionary past.

In the end, my gripe is not with vegetarians or vegans or with those people who choose to eat animal food. My beef is with people who set out to promote their beliefs by appealing to anti-intellectualism.

Dishonest people who eschew the evidence and contestability of ideas that lie at the heart of science for personal, political or financial gain.

Those self-appointed experts who set out to deliberately deceive us by using pseudoscience or plain old bullshit to construct their own version of our past.

The ConversationDarren Curnoe, ARC Future Fellow and Director of the Palaeontology, Geobiology and Earth Archives Research Centre (PANGEA), UNSW Australia

This article was originally published on The Conversation. (Reblogged by permission). Read the original article.

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Bone suggests ‘Red Deer Cave people’ a mysterious species of human

The Conversation

Darren Curnoe, UNSW Australia

It’s been an exciting year for human evolution with several discoveries dramatically rewriting major episodes of our ancient past.

Some of this progress stems from major advances in fields like ancient genomics, while much has resulted from new fossil and archaeological discoveries made in Africa and China.

What’s interested me the most has been the discovery of archaic humans living in northern China until perhaps 70,000 years ago and the oldest anatomically modern humans in the region appearing at least 80,000 years ago.

This is because they fall squarely within my own area of research: human evolution over the past few hundred thousand years in East Asia and Australasia.

Unlike anything else

In 2012, we announced the discovery of the ‘Red Deer Cave people’ in Southwest China, a mysterious human group we identified from cranial and jaw bones and teeth from two cave sites located in Southwest China.

Today, a team I co-lead with Professor Ji Xueping of the Yunnan Institute of Cultural Relics and Archaeology, and involving colleagues from a range of institutions in China and Australia, announced the discovery of yet another highly unusual bone from the Red Deer Cave people. And it seems to confirm they were a mysterious group of pre-modern humans.

The Red Deer Cave (Maludong) during research in 2008.
Ji Xueping & Darren Curnoe, Author provided

Our previous work showed that the features of their bones and teeth possess a remarkable number of similarities to archaic humans. This is despite them having lived only between about 14,000 and 11,000 years ago from radiocarbon dating of charcoal.

Their anatomy was nothing like we’d seen before in modern humans, whether they lived 200,000 or 200 years ago: they were truly unique and a real mystery to us and many of our colleagues.

We suggested they could represent either a very early modern human population, perhaps one that settled the region more than 100,000 years ago and became isolated. Or, they could be a late surviving archaic species, akin to a population of Neanderthals surviving in isolation until the end of the Ice Age in Southwest China.

Some of our colleagues also proposed at the time that they might be hybrids between modern humans and an unknown archaic species as an explanation for their peculiar traits.

We had focused our work on the skulls and teeth, representing four or five individuals, thinking they would offer the best insights into just who these mysterious people might be.

But, alas, we were left with considerable uncertainty. There was no clear answer about which species they might belong to or whether they could be hybrids. So back to work we went.

Archaic or hybrid?

A couple of months ago we published a new study of the Longlin or Laomaocao Cave specimen, which we had also placed in the Red Deer Cave people in 2012.

We’re now treating it as part of a separate group, distinct from the bones from Red Deer Cave, or Maludong, and one that we now think is indeed very likely to be a hybrid. And direct dating on human bone now confirms that the specimen is only 10,500 years old.

The Longlin Cave cranium.
Darren Curnoe, Author provided

If we’re correct, then either there were archaic humans still around at that time in Southwest China who interbred with modern humans, or their hybrid features persisted longer after interbreeding occurred because of isolation and perhaps through the action of natural selection or genetic drift.

Our study published this week outlines detailed work on a thigh bone or femur from Maludong, located only 6km Southwest of the city of Mengzi, near the Northern Vietnam border.

Like the skull bones from the site, it is also dated to about 14,000 years old. But unlike them, it provides a much clearer indication of what at least some of the Red Deer Cave people bones might be.

Our work shows that the thigh bone strongly resembles very ancient species like early Homo erectus or Homo habilis, which lived around 1.5 million years ago or more in Africa.

Red Deer Cave people thigh bone compared with a modern human (not to scale).
Darren Curnoe, Ji Xueping & Getty Images, Author provided

Like these pre-modern humans, the Maludong femur is very small. The shaft is narrow, with the outer layer of the shaft (or cortex) very thin, the walls of the shaft are reinforced (or buttressed) in areas of high strain, the femur neck is long, and the place of muscle attachment for the primary flexor muscle of the hip (the lesser trochanter) is very large and faces strongly backwards.

Surprisingly, we reconstructed its body mass to be about 50 kilograms, making the the individual very small by pre-modern and Ice Age human hunter-gatherer standards.

We need to be a bit careful though, as it is only one bone. Still, when seen in the context of the archaic looking skull bones and teeth from Maludong, our results are very compelling.

Controversies

How is it that such an ancient looking species could have survived until so recently in Southwest China? Well, the environment and climate of Southwest China is unique owing to the tectonic uplift of the Qinghai-Tibetan Plateau.

Yunnan Province today has the greatest biodiversity of plants and animals in the whole of China. It is one of 20 floristic endemic centres as a result of its complex landscape of high mountains, deep valleys, rift lakes and large rivers.

The region around Maludong is also biogeographically on the northern edge of tropical Southeast Asia and many species found there today are very ancient indeed. The area is a biological refugium owing to its variable topography and tropical location.

The Maludong femur might therefore represent a relic, tropically adapted, archaic population that survived relatively late in this biogeographically complex, highly diverse and largely isolated region.

Now, we can’t deny that our work is controversial, with some our colleagues simply unable to accept the possibility that archaic looking bones could be so young, especially in East Asia.

Yet, when Homo floresiensis was found a decade ago the same kinds of comments were made. This species looks a lot like Australopithecus skeletons, like Lucy), that lived in Africa 3 or 4 million years ago. While not everyone has accepted the so-called “Hobbit” from Flores as a valid new species, most anthropologists and archaeologists have.

At a conference in Shanghai this week, which I attended, scientists from the Russian Academy of Science in Siberia presented evidence about the cave of Denisova in southern Siberia. Coincidentally, a new article by the same team on Denisovan DNA also come out this week in the Proceedings of the National Academy of Sciences of the USA.

It was a big surprise to me to learn that they have found rather similar kinds of things at Denisova Cave, except that the bones are 30,000-40,000 years older than at Maludong.

They’ve recovered evidence for multiple archaic species like the Neanderthals and Denisovans in the same cave layers as modern human dating to about 50,000 year ago. And in a slightly older unit in the cave they have found Neanderthal, Denisovan and possible Homo erectus bones, again together from a single layer.

Within this context, and the Hobbit from Indonesia, our finds don’t look so out of place after all.

The author and colleague Ji Xueping at a Palaeolithic cave in southern China.
Ji Xueping & Darren Curnoe, Author provided

Riddles

We need to also keep in mind that most of what we know about human evolution is based on the fossil records of Europe and some parts of Africa, like the East African Rift Valley, and caves in South Africa.

We’re quickly learning that Europe and Africa may not provide the best model for us to use to interpret the fossil record of East Asia. For example, Denisova Cave is as far east as we’ve found the Neanderthals, and they don’t seem to have occupied Siberia permanently. This is unlike Europe, where they lived until about 40,000 years ago. And so far, no Neanderthals have been found in China or anywhere further South of Denisova Cave.

The fact is that we’ve really only scratched the surface in East Asia. We still have an enormous amount to learn about which species were living there when the first modern humans arrived, and about how they interacted with the Palaeolithic ancestors of living East Asians.

Despite the progress we’re making about these and other ancient humans in Southwest China, we’re left with many riddles still about the Red Deer Cave people. Just who exactly were these mysterious Stone Age people? Why did they survive so late? Why are they found only in tropical Southwest China?

What did modern humans make of them? And how did they interact with them when they encountered them? Did they interbreed with them?

We hope to be able to answer more of these questions soon.

The ConversationDarren Curnoe, ARC Future Fellow, UNSW Australia

This article was originally published on The Conversation. (Reblogged by permission). Read the original article.

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