Posts Tagged ‘Africa’

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The discarded bone of a chicken leg, still etched with teeth marks from a dinner thousands of years ago, provides some of the oldest known physical evidence for the introduction of domesticated chickens to the continent of Africa, research from Washington University in St. Louis has confirmed.

Based on radiocarbon dating of about 30 chicken bones unearthed at the site of an ancient farming village in present-day Ethiopia, the findings shed new light on how domesticated chickens crossed ancient roads — and seas — to reach farms and plates in Africa and, eventually, every other corner of the globe.

“Our study provides the earliest directly dated evidence for the presence of chickens in Africa and points to the significance of Red Sea and East African trade routes in the introduction of the chicken,” said Helina Woldekiros, lead author and a postdoctoral anthropology researcher in Arts & Sciences at Washington University.

The main wild ancestor of today’s chickens, the red junglefowl Gallus gallus is endemic to sub-Himalayan northern India, southern China and Southeast Asia, where chickens were first domesticated 6,000-8,000 years ago. Now nearly ubiquitous around the world, the offspring of these first-domesticated chickens are providing modern researchers with valuable clues to ancient agricultural and trade contacts.

The arrival of chickens in Africa and the routes by which they both entered and dispersed across the continent are not well known. Previous research based on representations of chickens on ceramics and paintings, plus bones from other archaeological sites, suggested that chickens were first introduced to Africa through North Africa, Egypt and the Nile Valley about 2,500 years ago.

The earliest bone-based evidence of chickens in Africa dates to the late first millennium B.C., from the Saite levels at Buto, Egypt — approximately 685-525 B.C.

This study, published in the International Journal of Osteoarchaeology, pushes that date back by hundreds of years. Co-authored by Catherine D’Andrea, professor of archaeology at Simon Fraser University in Canada, the research also suggests that the earliest introductions may have come from trade routes on the continent’s eastern coast.

“Some of these bones were directly radiocarbon dated to 819-755 B.C., and with charcoal dates of 919-801 B.C. make these the earliest chickens in Africa,” Woldekiros said. “They predate the earliest known Egyptian chickens by at least 300 years and highlight early exotic faunal exchanges in the Horn of Africa during the early first millennium B.C.”

Despite their widespread, modern-day importance, chicken remains are found in small numbers at archaeological sites. Because wild relatives of the galliform chicken species are plentiful in Africa, this study required researchers to sift through the remnants of many small bird species to identify bones with the unique sizes and shapes that are characteristic of domestic chickens.

Woldekiros, the project’s zooarchaeologist, studied the chicken bones at a field lab in northern Ethiopia and confirmed her identifications using a comparative bone collection at the Institute of Paleoanatomy at Ludwig Maximillian University in Munich.

Excavated by a team of researchers led by D’Andrea of Simon Fraser, the bones analyzed for this study were recovered from the kitchen and living floors of an ancient farming community known as Mezber. The rural village was located in northern Ethiopia about 30 miles from the urban center of the pre-Aksumite civilization. The pre-Aksumites were the earliest people in the Horn of Africa to form complex, urban-rural trading networks.

Linguistic studies of ancient root words for chickens in African languages suggest multiple introductions of chickens to Africa following different routes: from North Africa through the Sahara to West Africa; and from the East African coast to Central Africa. Scholars also have demonstrated the biodiversity of modern-day African village chickens through molecular genetic studies.

“It is likely that people brought chickens to Ethiopia and the Horn of Africa repeatedly over long period of time: over 1,000 years,” Woldekiros said. “Our archaeological findings help to explain the genetic diversity of modern Africans chickens resulting from the introduction of diverse chicken lineages coming from early Arabian and South Asian context and later Swahili networks.”

These findings contribute to broader stories of ways in which people move domestic animals around the world through migration, exchange and trade. Ancient introductions of domestic animals to new regions were not always successful. Zooarchaeological studies of the most popular domestic animals such as cattle, sheep, goats and pigs have demonstrated repeated introductions as well as failures of new species in different regions of the world.

“Our study also supports the African Red Sea coast as one possible early route of introduction of chickens to Africa and the Horn,” Woldekiros said. “It fits with ways in which maritime exchange networks were important for global distribution of chicken and other agricultural products. The early dates for chickens at Mezber, combined with their presence in all of the occupation phases at Mezber and in Aksumite contexts 40 B.C.- 600 A.D. in other parts of Ethiopia, demonstrate their long-term success in northern Ethiopia.”

Source: How the chicken crossed the Red Sea


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Topic: shellfish and migration

Artefacts from the African Middle Stone Age (MSA; ∼200 to ∼50 ka), provide us with the first glimpses of modern human art and culture. Approximately 50 ka, one or more subgroups of modern humans expanded from Africa to populate the rest of the world.

Significant behavioural change accompanied this expansion, and archaeologists commonly seek its roots during this period. Recognizable art objects and “jewellery” become common only in sites that postdate the MSA in Africa and Eurasia, but some MSA sites contain possible precursors, including abstractly incised fragments of ochre and perforated mollusc shells interpreted as beads.

Was population growth the driver of change?

Researchers had previously theorised that it was an increase in population that drove behavioural innovations which in turn led to the creation of these artefacts and eventually, the expansion out of Africa. However, by examining mollusc shells from Stone Age sites, Richard Klein of Stanford University and Teresa Steele of University of California, Davis, have determined that a significant population increase did not occur until the Later Stone Age (LSA), after the out of Africa migration had already begun. Their research appears in the June 2013 edition of the Proceedings of the National Academy of Sciences.

Archaeologists have found precursors of modern human artwork and jewellery, including fragments of ochre with abstract incisions and shells with perforations, in MSA sites and it is therefore concluded that the humans who made them, between 85,000 and 65,000 years ago, must have had modern cognitive abilities and behaviours. During the LSA, these abilities and behaviours allowed humans to create objects as recognizable art and spurred the migration to Eurasia.

Population growth has been the popular explanation for the innovations of the MSA. As population increases, the opportunity for innovation increases, while concurrently, the probability that an idea will be lost decreases.

Symbolic thought in the form of decorative art appears in excavations at Blombos Cave on the southern Cape coast from about 75 ka, associated with small perforated shells that retain traces of red ochre. This suggests that they had been collected and strung together as a necklace. In the underlying level dated to about 80 ka, two pieces of ochre were found, engraved with a pattern of lines that formed diamond shapes. The question to be asked is how and when this transformation to modern human behaviour began.

Testing a new hypothesis

To test the hypothesis that a large increase in population drove MSA innovation, Klein and Steele measured the shells of slow-growing molluscs found in MSA and LSA middens on the southern and western coasts of South Africa. They reasoned that selection pressure, caused by an increase in human population, would decrease median shell size. Frequent foraging by large numbers of humans would have prevented many shellfish from reaching their full size.

Pinnacle Point Cave 13B, South Africa and Bajondillo Cave, Spain show that human shellfishing began at least 160–150 ka, during the MSA in Africa and the coeval Middle Palaeolithic (also known as Mousterian) of Europe.

The researchers found that the median size of MSA shells was larger than that of LSA shells. This showed that selection pressure, and therefore human population, was greater in the LSA rather than the MSA. In addition, shellfish from smaller species were more common in LSA than in newer Stone Age sites. As selection pressure increased with population size, humans would be less likely to overlook smaller shellfish as a source of food.

Need for more data

Klein and Steele claim that because the population increase did not occur until after the migration out of Africa had already begun, there must be another explanation for the cultural advancements of the MSA. They hope that other sites around the African coasts, especially northwest Africa, can be used to investigate the possibility that MSA molluscs that were collected as a foodsource were generally larger than those in later sites and thus add weight to the evidence that MSA population growth did not underlie innovation.

Alternative explanations, particularly for the birth of cognitive and behavioural innovation at the MSA/LSA interface, include the pressure of late Pleistocene climatic fluctuations and perhaps even changes in the human genome that ancient DNA analyses promises to reveal.

Original article:
past horizons
June 22, 2013


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Topic: Early Man

In the middle of an African desert, with no water to be found for miles, scattered shells, fishing harpoons, fossilised plants and stone tools reveal signs of life from the water’s edge of another era. In 40°C heat, anthropologists Dr Marta Mirazón Lahr and Professor Robert Foley from Cambridge’s Leverhulme Centre for Human Evolutionary Studies (LCHES) are painstakingly searching for clues to the origin and diversification of modern humans, from the artefacts they left behind to the remains of the people themselves.

Kenya, East Africa, has long been known as the ‘cradle of mankind’ following the discovery of fossils thought to be of the first members of the human family, which arose in Africa around 6–7 million years ago. Various distinct species evolved from these ancestors over millions of years, including our own – Homo sapiens – around 250,000 years ago.

Tip of a massive population expansion

“A lot of the research on the origins of modern humans has focused on defining their point of origin, then understanding why humans left Africa about 60,000 years ago to colonise the rest of the world – known as the Out of Africa model,” said Mirazón Lahr. “But we have no idea what happened between 200,000 years and 60,000 years ago. We also have very little information on what occurred inside Africa after 60,000 years, when the different population groups and languages we see today evolved. The genetics suggest that the expansion out of Africa is just the tip of a massive population expansion inside the continent.”

Mirazón Lahr’s In Africa project, recently awarded five-year funding from the European Research Council, is investigating the evolutionary history of modern human populations. “The challenge is to find the sites where evidence of these early people can be recovered – their stone tools, the animals they hunted, their ornaments and, ultimately, the fossils of the people themselves,” she said.

East Africa has played a central role in all earlier phases of human evolution. She has chosen to focus on this region based on the theory that its past environment was suitable for sustained occupation over time. But East Africa is huge, and finding the right place to look is absolutely crucial. Mirazón Lahr used satellite technology to find the first clues.

Using satellite images

“In the past there were periods of enormous rainfall in the tropics. When glaciers melted in the northern hemisphere, due to climate change, the water evaporated and then fell in the tropics as monsoon rains,” she said. “The lakes were much higher and their margins were wider. We are using satellite images of the region to reconstruct where the ancient lake margins would have been when the lakes were last high, and that’s where we look.”

Mirazón Lahr and Foley have already carried out three field expeditions, in 2009, 2010 and 2011, to investigate their two chosen sites: the Turkana and the Nakuru-Naivasha basins of the Rift Valley in Kenya, and have made some spectacular finds on the ancient Turkana beaches.

“Ten thousand years ago, this area was wetter, with gazelles, hippos and lions, and the beaches are still there even though the water is long gone. We’ve found shells on the surface, and harpoons the people used to fish with. We go there and we just walk,” said Mirazón Lahr. “A lot has already been exposed by the wind, and occasionally we find sites where things are buried, and then we dig.”

“We’re looking at the lithics – stone tools – and how these relate to times of particularly high lake levels,” said Mirazón Lahr. “Then we’re looking at the fauna and, if we’re lucky, we find actual human fossils. The oldest fossil ever found that looks like a modern human is 200,000 years old, and comes from the basin of Lake Turkana. We’re trying to find the fossils that mark the origin of Homo sapiens. The ancient Turkana beach is an incredibly fossil-rich site, and we’ve already found such exciting things!

“We have many human remains – about 700 fragments – mostly dating from between 12,000 and 7,000 years ago, which match the age of this beach. To do the population biology and answer the questions about diversity we need these large numbers. This is already the biggest collection of this age in Africa.”

Changing technologies

The primitive technologies that our early ancestors left behind change over time, and comparing finds dated to different times can advance understanding of our evolutionary trajectory. “We think the evolution to modern humans is associated with changes in behaviour and in technology, for example in their tool use,” said Mirazón Lahr. “We’ve already found evidence that they started using animal bones to make tools, which was rare in earlier populations.”

“The people who lived around this lake 10,000 years ago used microliths – a form of miniaturised stone tool technology,” said Foley. “Instead of producing one or two big flakes like the earliest modern humans, they produced lots of very small flakes to make composite tools. This is a sign of the flexibility of the way modern humans adapted to different conditions. We’ve also found a beach in the Turkana Basin from about 200,000 years ago and that has its own very different fossilised fauna, and very different stone tools. The technology and the people changed a lot over the past 200,000 years.”

Geography and climate played a critical role

Mirazón Lahr emphasises that geography and climate played a critical role in the origins and diversification of modern humans. “The times when the lakes were high were periods of plenty in East Africa,” she said. “When it was very wet there were lots of animals, the vegetation could grow, and you can imagine that the people would have thrived.” East Africa had a unique mosaic environment with lake basins, highlands and plains that provided alternative niches for foraging populations over this period. Mirazón Lahr believes that these complex conditions were shaped by varying local responses to global climate change.

“We think that early modern humans could live in the region throughout these long periods, even if they had to move between basins.” With a network of habitable zones, human populations survived by expanding, contracting and shifting ranges according to the changing conditions. By comparing the fossil records from different basins over time, Mirazón Lahr hopes to establish a spatial and temporal pattern of human occupation over the past 200,000 years.

Her approach is a multidisciplinary one, combining genetic, fossil, archaeological and palaeoclimatic information to form an accurate picture of events. Drawing on her wide-ranging interests from molecular genetics to lithics and prehistory, she believes that the way to find novel insights is to consider each problem from various angles.

This approach is intrinsic to the In Africa project, in which she and Foley are not just searching for new fossils, but also trying to build a complete picture of our early ancestors’ lives and the external forces that shaped their evolution, both biological and behavioural. “The project will be one of the first investigations into humans of this date in East Africa,” said Foley. “Given Africa is where we all come from, that’s critical.”

Original article:

past horizons
Source:Cambridge university


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Topic Early tools

On the south coast of South Africa, scientists have found evidence for an advanced stone age technology dated to 71,000 years ago at Pinnacle Point near Mossel Bay. This technology, allowing projectiles to be thrown at greater distance and killing power, takes hold in other regions of Africa and Eurasia about 20,000 years ago. When combined with other findings of advanced technologies and evidence for early symbolic behavior from this region, the research documents a persistent pattern of behavioral complexity that might signal modern humans evolved in this coastal location. These findings were reported in the article “An Early and Enduring Advanced Technology Originating 71,000 Years Ago in South Africa” in the November 7 issue of the journal Nature.

“Every time we excavate a new site in coastal South Africa with advanced field techniques, we discover new and surprising results that push back in time the evidence for uniquely human behaviors,” said co-author Curtis Marean, project director and Arizona State University professor in the Institute of Human Origins, a research center of the College of Liberal Arts and Sciences in the School of Human Evolution and Social Change.

The reported technology focused on the careful production of long, thin blades of stone that were then blunted (called “backing”) on one edge so that they could be glued into slots carved in wood or bone. This created light armaments for use as projectiles, either as arrows in bow and arrow technology, or more likely as spear throwers (atlatls). These provide a significant advantage over hand cast spears, so when faced with a fierce buffalo (or competing human), having a projectile weapon of this type increases the killing reach of the hunter and lowers the risk of injury. The stone used to produce these special blades was carefully transformed for easier flaking by a complex process called “heat treatment,” a technological advance also appearing early in coastal South Africa and reported by the same research team in 2009.

“Good things come in small packages,” said Kyle Brown, a skilled stone tool replicator and co-author on the paper, who is an honorary research associate with the University of Cape Town, South Africa. “When we started to find these very small carefully made tools, we were glad that we had saved and sorted even the smallest of our sieved materials. At sites excavated less carefully, these microliths may have been discarded in the back dirt or never identified in the lab.”

Prior work showed that this microlithic technology appear briefly between 65,000 and 60,000 years ago during a worldwide glacial phase, and then it was thought to vanish, thus showing what many scientists have come to accept as a “flickering” pattern of advanced technologies in Africa. The so-called flickering nature of the pattern was thought to result from small populations struggling during harsh climate phases, inventing technologies, and then losing them due to chance occurrences wiping out the artisans with the special knowledge.

“Eleven thousand years of continuity is, in reality, an almost unimaginable time span for people to consistently make tools the same way,” said Marean. “This is certainly not a flickering pattern.”

The appearance and disappearance is more likely a function of the small sample of well-excavated sites in Africa. Because of this small sample, each new site has a high probability of adding a novel observation. The African sample is a tiny fraction of the known European sample from the same time period.

“This is why continued and well-funded fieldwork in Africa is of the highest scientific priority if we want to learn about what it means to be human, and where and when it happened,” said Marean.

The site where this technology was discovered is called Pinnacle Point 5-6 (PP5-6). This spectacular site preserves about 14 meters of archaeological sediment dating from approximately 90,000 to 50,000 years ago. The documentation of the age and span of the technology was made possible by an unprecedented fieldwork commitment of nine, two-month seasons (funded by the National Science Foundation and Hyde Family Foundation) where every observed item related to human behavior was plotted directly to a computer using a “total station.” A total station is a surveying instrument that digitally captures points where items are found to create a 3D model of the excavation. Almost 200,000 finds have been plotted to date, and excavations continue. This was joined to over 75 optically stimulated luminescence dates by project geochronologist Zenobia Jacobs at the University of Wollongong (Australia), creating the highest resolution stone-age sequence from this time span.

“As an archaeologist and scientist, it is a privilege to work on a site that preserves a near perfect layered sequence capturing almost 50,000 years of human prehistory,” said Brown, who codirected excavations at PP5-6. “Our team has done a remarkable job of identifying some of the subtle but important clues to just how innovative these early humans on the south coast were.”

Research on stone tools and Neanderthal anatomy strongly suggests that Neanderthals lacked true projectile weapons.

“When Africans left Africa and entered Neanderthal territory they had projectiles with greater killing reach, and these early moderns probably also had higher levels of pro-social (hyper-cooperative) behavior. These two traits were a knockout punch. Combine them, as modern humans did and still do, and no prey or competitor is safe,” said Marean. “This probably laid the foundation for the expansion out of Africa of modern humans and the extinction of many prey as well as our sister species such as Neanderthals.”

Original article:
November7, 2012

Photos are of the excavation site is at Pinnacle Point, Mossel Bay, on the southern coast of South Africa. The cave opening is in the center of the top image.



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Topic Diet change

I don’t think I posted this before, I looked through my past entries and didn’t see it.

Have a good weekend!

Disappearance of the elephant caused rise of modern humans: Dietary change led to modern humans in Middle East 400,000 years ago.

Original article:


Dec 2011

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Topic: Hunters

Map of Oman

Trail of ‘stone breadcrumbs’ reveals the identity of 1 of the first human groups to leave Africa.

Original Article:


Nov, 2011

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