Tag Archives: ancient human

First human ancestor to walk on two legs made its final stand in Java

A million years before humans made their first baby steps out of Africa, one of our ancestors was already busy fashioning tools and exploring the world walking on two legs. Homo erectus is famous for being the first hominin to walk upright. Now, a new study suggests that our ancestor was the most successful member of the genus Homo, having survived from 1.8 million years ago until as recently as 108,000 years ago.

The Ngandong site. Credit: Russel Ciochon.

The Ngandong terrace, a floodplain on the Indonesian island of Java, is the site of the largest collection of Homo erectus fossils in the world, showing that the human ancestor was able to travel a huge distance from its birthplace in Africa. Nearly a century ago, anthropologists have unearthed at least a dozen partial skulls and two shin bones at the site.

For a long time, scientists have tried to date the site, but until recently all these efforts return wildly different estimates from as early as 27,000 to half a million years old. The fact that the original bonebed first excavated by Dutch geologists in the 1930s had been lost made the investigation all the more challenging.

In their new study, researchers at the University of Iowa and the Institute of Technology in Bandung, Indonesia, used modern techniques (uranium-series dating, luminescence, and electron-spin resonance) to date the landscape and some animal fossils excavated from the Ngandong terrace. To find the original bonebed, the researchers employed maps and journals inherited by the grandchildren of one of the Dutch geologists.

Ngandong bonebed. Credit: University of Iowa.

They also dated the stalagmites in the caves of nearby mountains, showing that the mountains themselves rose at least half a million years ago, diverting the Solo river into the Kendeng hills and forming the Ngandong terrace. Entangling the thread even further, the researchers found that the terrace is between 140,000 and 92,000 years old.

Although they couldn’t find new Homo erectus fossils, the researchers gathered hundreds of animal remains — ranging from water buffalo to elephants — which were found in the same layer as the Homo erectus skulls. Using a sophisticated computer model, the researchers weighed the different dates for each fossil, coming up with an age range of the site.

They conclude that although Homo erectus went extinct in many other parts of the world by this date, the species survived on Java until 108,000 to 117,000 years ago. Modern humans arrived on the island about 35,000 years after the last known appearance of Homo erectus.

“This site is the last known appearance of Homo erectus found anywhere in the world,” says Russell Ciochon, co-corresponding author on the study. “We can’t say we dated the extinction, but we dated the last occurrence of it. We have no evidence Homo erectus lived later than that anywhere else.”

A Homo erectus skull cap found at the Ngandong site. Credit: Griffith University.

This means that around the same time, our species, Homo sapiens, shared the planet with at least seven other different hominin species, including Denisovans and Neanderthals.

Around 130,000 years ago, the environment at Ngandong changed, and perhaps this may have sealed Homo erectus’ fate.

“There was a change in climate,” Ciochon explains. “We know the fauna changed from open country, grassland, to a tropical rainforest (extending southward from today’s Malaysia). Those were not the plants and animals that Homo erectus was used to, and the species just could not adapt.”

However, considering that the researchers couldn’t find direct evidence of Homo erectus fossils, the debate isn’t settled yet. For instance, the animals at the site could have been butchered by Denisovans whose presence in the area is established. More research may provide more insight in order to clear some of the mist surrounding the Ngandong site.

The findings appeared in the journal Nature.

Stone tools from Kharga Oasis, Egypt, one of the archaeological sites used in the study. Photograph reproduced with kind permission from The British Museum

Early modern humans were culturally diverse before leaving Africa

Stone tools from Kharga Oasis, Egypt, one of the archaeological sites used in the study. Photograph reproduced with kind permission from The British Museum

Stone tools from Kharga Oasis, Egypt, one of the archaeological sites used in the study. Photograph: The British Museum

Early modern human populations were culturally diverse and sometimes exchanged tools helped by river networks in a then savanna rich Sahara, according to the biggest ever comparative study of stone tools dating to between 130,000 and 75,000 years ago. At least four distinct populations, each relatively isolated from each other, have been identified as possessing distinct cultural practices.

Different tools, different cultures

The researchers from the University of Oxford, Kings College London and the University of Bordeaux took over 300,000 measurements of stone tools from 17 archaeological sites across North Africa, including the Sahara. Before early humans left Africa to settle communities in Eurasia, the Sahara we know today as a barren and inhospitable wasteland was considerably different. There were widespread areas filled with patchwork of savanna, grasslands and water, while the desert was interspersed between.

When assessing how ancient communities developed, it’s important to have a really accurate picture of how the climate was at the time, being an important element that puts things into context. With this in mind, the researchers studied climate models coupled with data about these ancient water courses, before finally matching these with new found data surrounding cutting tools. Because Africa’s extremely hot climate, ancient DNA has yet to be found and the most reliable artifacts that document the existence of early modern humans continue to be stone tools.

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Armed with this new found data, the researchers were able to infer the context in which the ancient populations made and used their tools. For the first time, tangible evidence was obtained that suggest early human communities were ‘budding’ with other populations along the ancient rivers and watercourses.

‘This is the first time that scientists have identified that early modern humans at the cusp of dispersal out of Africa were grouped in separate, isolated and local populations. Stone tools are the only form of preserved material culture for most of human history. In Africa, owing to the hot climate, ancient DNA has not yet been found. These stone tools reveal how early populations of modern humans dispersed across the Sahara just before they left North Africa. While different populations were relatively isolated, we were interested to find that when connected by rivers, they share similarities in their tool-making suggesting some interaction with one another,’ said Dr Eleanor Scerri, visiting scholar at the University of Oxford.

The researchers were careful to remove some of the causes that produce variability, but were not particularly tied to cultural characteristics, like raw materials.

‘Not much is known about the structure of early modern human populations in Africa, particularly at the time of their earliest dispersals into Eurasia. Our picture of modern human demography around 100,000 years ago is that there were a number of populations, varying in size and degree of genetic contact, distributed over a wide geographical area. This model of our population history supports other theories recently put forward that modern humans may have first successfully left Africa earlier than 60,000-50,000 years ago, which had been the common view among scholars. Our work provides important new evidence that sheds light on both the timing of early modern human dispersals out of Africa and the character of our interaction with other human species, such as Neanderthals,’ said Scerri.

Thanks to a growing body of evidence, the paradigm has shifted from asking whether or not humans originated from Africa, then spread out to the rest of the world, to the question ‘which of these distinct populations went in and out of Africa?’. A crucial next step involves fieldwork in areas such as the Arabian Peninsula to understand how these populations spread into Eurasia.

The findings were reported in the journal Quaternary Science Reviews.

Area A at Happisburgh: View of footprint surface looking south, also showing underlying horizontally bedded laminated silts. (c) PLOS ONE

Oldest footprints discovered in Europe are 800,000 years old

Area A at Happisburgh: View of footprint surface looking south, also showing underlying horizontally bedded laminated silts. (c) PLOS ONE

Area A at Happisburgh: View of footprint surface looking south, also showing underlying horizontally bedded laminated silts. (c) PLOS ONE

Right on the English coast, near Happisburgh, scientists discovered what so far are the  earliest footprints discovered thus far in Europe, dated  800,000 years old. Some five human ancestors left these historical footprints in mud on the bank of an ancient river estuary. Perfect timing and the geological circumstances of the time allowed the prints to be preserved until the present.

As one might imagine, the chances of coming across a find such as this is extremely rare, after all we’re not talking about some fossil, but one of the oldest walks of fame ever.  Only those at Laetoli in Tanzania at about 3.5 million years and at Ileret and Koobi Fora in Kenya at about 1.5 million years are older. If this wasn’t enough, weren’t for the researchers’ keen eye on the site who were there for a completely different matter – a regular geological survey – just two weeks later the tide would have eroded the prints away forever.

“At first we weren’t sure what we were seeing,” explains Dr Nick Ashton of the British Museum “but as we removed any remaining beach sand and sponged off the seawater, it was clear that the hollows resembled prints, and that we needed to record the surface as quickly as possible.”

The team of researchers studied the shallow prints using photogrammetry, a technique that can stitch together digital photographs to create a permanent record and 3D images of the surface. The analysis eventually confirmed that the prints indeed were of ancient human origin, a mix of both adults and children. In some cases the heel, arch and even toes could be identified, equating to modern shoes of up to UK size 8.

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This latest find joins other breakthroughs gathered from the area, since a series of sites with stone tools and fossil bones have been discovered in the same sediments at Happisburgh over the past 10 years. It’s impossible to tell what the ancient humans were up to from the prints alone. Some 800,000 years ago Britain was a whole lot different. First of all, it wasn’t much of an island, since it was linked to continental Europe. Ancient mammals like bison, mammoth, hippo and rhino grazed the river valley at Happisburgh, while our early ancestors were surely lurking about next to them.

The findings were reported in the journal PLOS ONE.