Category Archives: SOUTH AFRICA

Could Homo Naledi Control Fire?

Could Homo Naledi Control Fire?

An ancient hominid dubbed Homo naledi may have lit controlled fires in the pitch-dark chambers of an underground cave system, new discoveries hint.

Could Homo Naledi Control Fire?
An ancient southern African hominid called Homo naledi, represented here by a child’s partial fossil skull, possibly used fire sometime between 335,000 and 236,000 years ago, new cave finds suggest.

Researchers have found remnants of small fireplaces and sooty wall and ceiling smudges in passages and chambers throughout South Africa’s Rising Star cave complex, paleoanthropologist Lee Berger announced in a December 1 lecture hosted by the Carnegie Institution of Science in Washington, D.C.

“Signs of fire use are everywhere in this cave system,” said Berger, of the University of the Witwatersrand, Johannesburg.

H. naledi presumably lit the blazes in the caves since remains of no other hominids have turned up there, the team says. But the researchers have yet to date the age of the fire remains. And researchers outside Berger’s group have yet to evaluate the new finds.

H. naledi fossils date to between 335,000 and 236,000 years ago (SN: 5/9/17), around the time Homo sapiens originated (SN: 6/7/17). Many researchers suspect that regular use of fire by hominids for light, warmth and cooking began roughly 400,000 years ago (SN: 4/2/12).

Such behavior has not been attributed to H. naledi before, largely because of its small brain. But it’s now clear that a brain roughly one-third the size of human brains today still enabled H. naledi to achieve control of fire, Berger contends.

Last August, Berger climbed down a narrow shaft and examined two underground chambers where H. naledi fossils had been found. He noticed stalactites and thin rock sheets that had partly grown over older ceiling surfaces. Those surfaces displayed blackened, burned areas and were also dotted by what appeared to be soot particles, Berger said.

Meanwhile, expedition codirector and Wits paleoanthropologist Keneiloe Molopyane led excavations of a nearby cave chamber. There, the researchers uncovered two small fireplaces containing charred bits of wood, and burned bones of antelopes and other animals.

Remains of a fireplace and nearby burned animal bones were then discovered in a more remote cave chamber where H. naledi fossils have been found, Berger said.

Still, the main challenge for investigators will be to date the burned wood and bones and other fire remains from the Rising Star chambers and demonstrate that the material comes from the same sediment layers as H. naledi fossils, says paleoanthropologist W. Andrew Barr of George Washington University in Washington, D.C., who wasn’t involved in the work.

“That’s an absolutely critical first step before it will be possible to speculate about who may have made fires for what reason,” Barr says.

Bone, wood and charcoal from the South African site should also be examined with various techniques to determine whether darkened areas resulted from burning or mineral staining, says Harvard University archaeologist Sarah Hlubik, who wasn’t involved in the research. And a careful analysis of the layout of remains in the Rising Star chambers, she adds, will indicate whether Berger’s group discovered small fireplaces built by cave visitors, or only bones and other material that washed into the cave system.

Scientists discover 80,000-year-old bone tools

Scientists discover 80,000-year-old bone tools

Scientists discover 80,000-year-old bone tools
From left to right: experimental debarking in Africa, the bone tool tip after use, Francesco d’Errico making replicas of an experimental bone tool in the field.

Until the beginning of this century, the production of fully worked bone tools was considered an innovation introduced in Europe around 40,000 years ago by modern humans.

Research carried out over the last two decades has led to the discovery of bone tools in several regions of Africa, some of which could date back 100,000 years.

But these early bone tools are rare and non-standardised in shape.

Key cultural innovations

The discovery of 23 bone tools from the Sibudu rock shelter, Kwa Zulu-Natal, South Africa, all with a flattened ogival-shaped end, found in archaeological layers dated between 80,000 and 60,000 years ago, changes the picture.

“Our new study documents the technology and function of the earliest fully shaped bone tools from this region. The discovery of these tools contributes to a better understanding of when and how these innovations arose, and what they were used for,” Francesco d’Errico says. He is the lead author of the paper just published in Scientific Reports.

d’Errico is part of the SapienCE team at the University of Bergen. The SapienCE Centre of Excellence consists of an interdisciplinary team of world-leading scientists. The aim of SapienCE is to improve our understanding of how and when Homo sapiens evolved into who we are today.

Specialised tools for debarking activities

“Our results suggest that the Sibudu double-bevelled tools were not used for hunting or hide processing activities, which are tasks the earliest bone tools have been traditionally associated with, but rather for functions devoted to the exploitation of vegetal resources,” d’Errico explains.

The research was carried out by analysing the use of wear on archaeological and experimental tools with a confocal microscope. This allowed the researchers to measure the roughness parameters of the wear left on the tooltips by use.

Textural and discriminant analysis indicate that most of the bone tools discovered were used in debarking activities, and possibly for digging in humus-rich soil, likely to extract roots or underground storage organs.

Standardised cultural traits

The scientists note that this type of tool continued to be used at this site for 20,000 years, despite the fact that the occupants radically changed the way they produced stone tools during this period.

“These bone tools certainly reflect a local cultural adaptation to a specific environment, as we do not find them elsewhere. Our results support a scenario in which some modern human groups in southern Africa developed and maintained specific, highly standardised cultural traits locally while sharing others across the subcontinent,” d’Errico says.

Complex technical systems

This also implies that MSA peoples had networks allowing the sharing of similar technologies, cultural practices, and new innovations over large territories, while simultaneously maintaining local cultural traits and traditions.

This study confirms that Middle Stone populations already had complex technical systems to help them gather a variety of resources.

The bark of the trees on which the researchers conducted the debarking experiments is not edible but still used in traditional African medicine.

The bark may have been used already 80,000 years ago for similar purposes by Southern African early modern humans.

Early Human Evolution: Hominin Fossils in “Cradle of Humankind” May Be a Million Years Older Than Thought

Early Human Evolution: Hominin Fossils in “Cradle of Humankind” May Be a Million Years Older Than Thought

Early Human Evolution: Hominin Fossils in “Cradle of Humankind” May Be a Million Years Older Than Thought
Four different Australopithecus crania were found in the Sterkfontein caves, South Africa. The Sterkfontein cave fill containing this and other Australopithecus fossils was dated to 3.4 to 3.6 million years ago, far older than previously thought. The new date overturns the long-held concept that South African Australopithecus is a younger offshoot of East African Australopithecus afarensis. Credit: Jason Heaton and Ronald Clarke, in cooperation with the Ditsong Museum of Natural History

The Famous Sterkfontein Caves deposit is 1 million years older than previously thought.

New dates for the Australopithecus-bearing Sterkfontein Cave deposit place South African hominin fossils at the centre of global paleo research.

Nearly four million years of hominin and environmental evolution are revealed by fossils found at the Sterkfontein Caves in South Africa. Research began at the site in 1936 when Robert Broom discovered the first adult hominin of the genus Australopithecus.

Since then it has become famous for the hundreds of Australopithecus fossils yielded from excavations of ancient cave infills, including iconic specimens such as the Little Foot skeleton and the cranium known as Mrs. Ples.

Ancient cave infill called ‘Member 4’ is where the majority of Sterkfontein’s wealth of Australopithecus fossils have been excavated from. In fact, it is the richest deposit of Australopithecus fossils in the world.

Over the last 56 years of University of the Witwatersrand-led research at Sterkfontein, the age of Member 4 at Sterkfontein has remained contested. Age estimates have ranged from as young as about 2 million years ago, younger than the appearance of our genus Homo, back to about 3 million years.

New research presented in a paper published in the journal Proceedings of the National Academy of Sciences (PNAS) re-evaluates the age of Australopithecus from Member 4 at Sterkfontein together with the Jacovec Cavern, which contains a few additional hominin fossils in a deeper chamber in the cave.

“The new ages range from 3.4-3.6 million years for Member 4, indicating that the Sterkfontein hominins were contemporaries of other early Australopithecus species, like Australopithecus afarensis, in east Africa,” says Professor Dominic Stratford, director of research at the caves, and one of the authors on the paper.

The new ages are based on the radioactive decay of the rare isotopes aluminium-26 and beryllium-10 in the mineral quartz.

“These radioactive isotopes, known as cosmogenic nuclides, are produced by high-energy cosmic ray reactions near the ground surface, and their radioactive decay dates when the rocks were buried in the cave when they fell in the entrance together with the fossils,” says Professor Darryl Granger of Purdue University in the United States and lead author on the paper.

Previous dating of Member 4 has been based on dating calcite flowstone deposits found within the cave fill, but careful observations show that the flowstone is actually younger than the cave fill and so it underestimates the age of the fossils.

“This re-assessment of the age of Sterkfontein Member 4 Australopithecus fossils has important implications for the role of South Africa on the hominin evolution stage. Younger hominins, including Paranthropus and our genus Homoappear between about 2.8 and 2 million years ago.

Based on previously suggested dates, the South African Australopithecus species were too young to be their ancestors, so it has been considered more likely that Homo and Paranthropus evolved in East Africa,” says Stratford.

The new dates show that Australopithecus existed at Sterkfontein almost a million years prior to the appearance of Paranthropus and Homo, providing more time for them to evolve here, in the Cradle of Humankind, and placing the hominins from this site front and centre in the history early human evolution.

“This important new dating work pushes the age of some of the most interesting fossils in human evolution research, and one of South Africa’s most iconic fossils, Mrs. Ples, back a million years to a time when, in east Africa, we find other iconic early hominins like Lucy,” says Stratford.

“The redating of the Australopithecus-bearing infills at the Sterkfontein Caves will undoubtedly re-ignite the debate over the diverse characteristics of Australopithecus at Sterkfontein, and whether there could have been South African ancestors to later hominins,” says Granger.

For more on this research, read Fossils in the “Cradle of Humankind” May Be More Than a Million Years Older Than Thought.

Fossils in the ‘Cradle of Humankind’ may be more than a million years older than previously thought

Fossils in the ‘Cradle of Humankind’ may be more than a million years older than previously thought

A group of Australopithecus afarensis.

The ‘Cradle of Humankind’ is a UNESCO World Heritage Site in South Africa that comprises a variety of fossil-bearing cave deposits, including Sterkfontein Caves. Sterkfontein was made famous by the discovery of the first adult Australopithecus in 1936.

Since then, hundreds of Australopithecus fossils have been found there, including the well-known Mrs. Ples and the nearly complete skeleton known as Little Foot.

“Sterkfontein has more Australopithecus fossils than anywhere else in the world. But it’s hard to get a good date on them,” said Purdue University’s Professor Darryl Granger.

“People have looked at the animal fossils found near them and compared the ages of cave features like flowstones and gotten a range of different dates.”

“What our data does is resolve these controversies. It shows that these fossils are old — much older than we originally thought.”

Forensic facial reconstruction of Australopithecus afarensis.

To determine the age of the Australopithecus-bearing sediments at Sterkfontein, the researchers measured radioactive cosmogenic nuclides — aluminium-26 and beryllium-10 — in the mineral quartz.

“Cosmogenic nuclides are extremely rare isotopes produced by cosmic rays — high-energy particles that constantly bombard the Earth,” they explained.

“These incoming cosmic rays have enough energy to cause nuclear reactions inside rocks at the ground surface, creating new, radioactive isotopes within the mineral crystals.”

“An example is aluminum-26: aluminium that is missing a neutron and slowly decays to turn into magnesium over a period of millions of years.”

“Since aluminum-26 is formed when a rock is exposed at the surface, but not after it has been deeply buried in a cave, we can date cave sediments — and the fossils within them — by measuring levels of aluminium-26 in tandem with another cosmogenic nuclide, beryllium-10.”

Life reconstruction of Australopithecus sediba commissioned by the University of Michigan Museum of Natural History.

The team’s results show that the entire Australopithecus assemblage at Sterkfontein dates to 3.4-3.7 million years ago.

These australopiths were thus early representatives of the genus, overlapping in age with a morphologically diverse range of mid-Pliocene hominins, including Australopithecus afarensis and Australopithecus deyiremeda at Burtele, Australopithecus bahrelgazali in Chad, Kenyanthropus platyops at Lake Turkana, and Australopithecus anamensis at Woranso-Mille.

“The Sterkfontein hominins predate ParanthropusHomo, and Australopithecus sediba at nearby sites in the Cradle of Humankind by over a million years,” the authors said.

In addition to the new dates at Sterkfontein based on cosmogenic nuclides, they made careful maps of the cave deposits and showed how animal fossils of different ages would have been mixed together during excavations in the 1930s and 1940s, leading to decades of confusion about the previous ages.

“What I hope is that this convinces people that this dating method gives reliable results,” Dr. Granger said.

“Using this method, we can more accurately place ancient humans and their relatives in the correct time periods, in Africa, and elsewhere across the world.”

The results were published this week in the Proceedings of the National Academy of Sciences.

Ancient eggshell in the Northern Cape hiding 300,000 years of history

Ancient eggshell in the Northern Cape hiding 300,000 years of history

Evidence from an ancient eggshell has revealed important new information about the extreme climate change faced by human early ancestors.

The research shows parts of the interior of South Africa that today are dry and sparsely populated, were once wetland and grassland 250,000 to 350,000 years ago, at a key time in human evolution.

Philip Kiberd and Dr Alex Pryor, from the University of Exeter, studied isotopes and the amino acid from ostrich eggshell fragments excavated at the early Middle Stone Age site of Bundu Farm, in the upper Karoo region of the Northern Cape.

The yellow pin shows the location of Bundu Farm in the Northern Cape.

It is one of very few archaeological sites dated to 250,000 to 350,000 in southern Africa, a time period associated with the earliest appearance of communities with the genetic signatures of Homo sapiens.

This new research supports other evidence, from fossil animal bones, that past community in the region lived among grazing herds of wildebeest, zebra, small antelope, hippos, baboons and extinct species of Megalotragus Priscus and Equus capensis, and hunted these alongside other carnivores, hyena and lions.

After this period of equitable climate and environment, the eggshell evidence — and previous finds from the site — suggests that 200,000 years ago cooler and wetter climates gave way to increasing aridity.

A process of changing wet and dry climates recognised as driving the turnover and evolution of species, including Homo sapiens.

The study, published in the South African Archaeological Bulletin, shows that extracting isotopic data from ostrich eggshells, which are commonly found on archaeological sites in southern Africa, is a viable option for open-air sites greater than 200,000 years old.

The technique which involves grinding a small part of the eggshell, to a powder allows experts to analyse and date the shell, which in turn gives a fix on the climate and environment in the past.

A fragment of ancient ostrich shell embedded in calcrete from Bundu Farm.

Using eggshells to investigate past climates is possible as ostriches eat the freshest leaves of shrubs and grasses available in their environment, meaning eggshell composition reflects their diet.

As eggs are laid in the breeding season across a short window, the information found in ostrich eggshells provides a picture of the prevailing environment and climate for a precise period of time.

Bundu Farm, where the eggshell was recovered is a remote farm 50km from the nearest small town, sitting within a dry semi-desert environment, which supports a small flock of sheep.

The site was first excavated in the late 1990s the site with material stored at the McGregor Museum, Kimberley (MMK).

The study helps fill a gap in our knowledge of this part of South Africa and firmly puts the Bundu Farm site on the map.

Philip Kiberd, who led the study, said: “This part of South Africa is now extremely arid, but thousands of years ago it would have been an Eden-like landscape with lakes and rivers and abundant species of flora and fauna.

Our analysis of the ostrich eggshell helps us to better understand the environments in which our ancestors were evolving and provides an important context in which to interpret the behaviours and adaptations of people in the past and how this ultimately led to the evolution of our species.

Fossil child skull from 2.2 million years ago reveals how humans outsmarted the other great apes

Fossil child skull from 2.2 million years ago reveals how humans outsmarted the other great apes

A fossil more than two million years old could help explain why man became so brainy.

The Taung fossil, an early hominid that was discovered in South Africa in 1924, was a significant feature that could shed light on the evolution of intelligence.

The Taung fossil, an early hominid that was discovered in South Africa in 1924, was a significant feature that could shed light on the evolution of intelligence.

Importantly it has a ‘persistent metopic suture’ – an unfused seam – in the frontal bone, which allows a baby’s skull to be pliable in childbirth. In great apes, this closes shortly after birth but in humans, it doesn’t fuse until around two years of age – allowing brain growth.

The unfused seam allows babies to be born with larger brains, and the delay in fusing allows the brain to grow larger in early life, reports Proceedings of the National Academy of Sciences.

The Taung fossil has become the ‘type specimen,’ or main model, of the genus Australopithecus africanus.

An australopithecine is any species of the extinct genera Australopithecus or Paranthropus that lived in Africa, walked on two legs and had relatively small brains.

Dr Dean Falk, of Florida State University, said: ‘These findings are significant because they provide a highly plausible explanation as to why the hominin brain might grow larger and more complex.

‘The persistent metopic suture, an advanced trait, probably occurred in conjunction with refining the ability to walk on two legs.

‘The ability to walk upright caused an obstetric dilemma.

‘Childbirth became more difficult because the shape of the birth canal became constricted while the size of the brain increased. The persistent metopic suture contributes to an evolutionary solution to this dilemma.

‘The later fusion was also associated with an evolutionary expansion of the frontal lobes, which is evident from the endocasts of australopithecines such as Taung.’

240,000-year-old ‘Child of Darkness’ human ancestor discovered in narrow cave passageway

240,000-year-old ‘Child of Darkness’ human ancestor discovered in narrow cave passageway

Deep within South Africa’s Rising Star cave system, in a dark passageway barely 6 inches (15 centimeters) wide, scientists have discovered the fragmented skull of a Homo naledi child they’re calling “Leti.” How the little skull ended up in such a remote part of the cave is a mystery, though the discoverers suspect it could be evidence of an intentional burial.

240,000-year-old ‘Child of Darkness’ human ancestor discovered in narrow cave passageway
The reconstructed skull of “Leti,” a young Homo naledi. The skull was found inside a tiny passageway deep within a South African cave, and probably dates back more than 241,000 years.

“Leti,” short for “Letimela,” or “Lost One” in the Setswana language of South Africa, probably lived between 335,000 and 241,000 years ago, based on the ages of other remains found in the enigmatic cave.

Fossil fragments belonging to about 24 Homo naledi individuals have been found in the cave system since 2013, when the first fossils from this human ancestor were discovered in what’s now known as the Dinaledi Chamber. 

The presence of so many individuals from a single species in the cave is mysterious. The only way in is a 39-foot (12 meters) vertical fracture known as “The Chute,” and geologists and spelunkers have so far found no evidence of alternative entrances into the passageways.

Leti’s small skull was found scattered in pieces on a limestone shelf about 2.6 feet (80 cm) above the cave floor. The spot sits in “a spiderweb of cramped passages,” Maropeng Ramalepa, a member of the exploration team, said in a statement. 

Research team members exploring the cave had to squeeze through spaces barely 6 inches (15 cm) wide when exploring the labyrinth of passages where Leti was found.
Teeth from the Homo naledi child “Leti.” The teeth indicate that Leti died around the time of the eruption of the first permanent molars, which would be between the ages of 4 and 6 in modern humans.

A complicated ancestor

The area is barely navigable for experienced spelunkers with modern equipment, according to a new paper published Thursday (Nov. 4) in the journal PaleoAnthropology. There is no evidence that animals carried the H. naledi bones into the cave — there are no gnaw marks or evidence of predation. The bones also appear to have been placed in the cave, not washed in, as they were not found mixed with sediment or other debris. 

That leaves open the possibility that more than 240,000 years ago, human ancestors with orange-size brains deliberately entered a dark, maze-like cave, perhaps through a vertical chute that narrows to 7 inches (18 cm) in places, and placed their dead inside. 

No tools or artifacts have been found alongside the Rising Star cave system fossils. There are few signs of other animals entering the caves, beyond two specimens of juvenile baboons, at least one of which may be much older than the Homo naledi remains. 

This human ancestor lived at the same time as early Homo sapiens, John Hawks, an anthropologist at the University of Wisconsin-Madison who studies the remains, told Live Science in 2017. Their apparent forays into the cave suggest that they were among modern humans’ smarter ancestors, and that they had mastered the use of fire to light their explorations, Hawks said. According to the Smithsonian National Museum of Natural History, H. naledi walked upright, stood about 4 feet, 9 inches (1.44 m) tall and weighed between 88 and 123 pounds (about 40 and 56 kilograms). 

The new skull — which fits into the palm of a modern human hand — should reveal more about H. naledi’s growth and development. While a few jaw fragments from juveniles have been found in the cave, this is the first time researchers have discovered bones from the skull case, or cranium. They also discovered six teeth.

Bones and teeth

The bones and teeth were found during an exploration of the narrow, twisting passageways around Dinaledi Chamber. Researchers mapped 1,037 feet (316 m) of these passageways, looking for evidence of another way into that chamber and several others nearby where remains have been found. They saw no evidence of another route. 

“Exploration of the narrow passages within the Dinaledi Subsystem involves considerable effort, navigating areas with irregular floors and walls, numerous obstructions and fissures less than 30 cm [11.8 inches] wide,” archaeologist Marina Elliott of Simon Fraser University in British Columbia, Canada, wrote in the PaleoAnthropology paper. 

The researchers did, however, find more fossils in this subterranean maze. These included the second-ever piece of evidence of a juvenile baboon in the cave; a single arm bone probably belonging to H. naledi; a trove of 33 bone fragments that also likely belonged to an H. naledi individual or individuals; and Leti. Details on Leti’s skull were also published Nov. 4 in the journal PaleoAnthropology. 

The partially preserved skull was broken into 28 fragments. When reconstructed, these fragments revealed much of the child’s forehead and some of the top of the head. The teeth consisted of four unworn permanent teeth and two worn baby teeth. Their development and wear indicate that the child was at the age where the first permanent molars were breaking through the gum. In a human child, this would correspond to about 4 to 6 years of age. It’s not known if H. naledi developed faster; if so, Leti may have been younger than 4 when he or she died.

The size of the skull indicates that Leti’s brain had a volume of between 29 and 37 cubic inches (480 and 610 cubic cm) — about 90% to 95% of the brain volume of adults of her species.

“[T]his begins to give us insight into all stages of life of this remarkable species,” Louisiana State University anthropologist Juliet Brophy, who led the study on Leti’s skull, said in the statement.

200,000-Year-Old Bedding Found in South Africa May Be World’s Oldest

200,000-Year-Old Bedding Found in South Africa May Be World’s Oldest

Archaeologists studying the interior of a cliffside cave in South Africa have found what may be the world’s oldest bedding, reports Cathleen O’Grady for Science magazine.

200,000-Year-Old Bedding Found in South Africa May Be World’s Oldest
Archaeologists discovered these fossilized fragments of grass deep inside South Africa’s Border Cave.

Dated to more than 200,000 years ago, the grass bedding—discovered in the Lebombo Mountains’ Border Cave—was placed atop layers of ash, perhaps to keep crawling insects like ticks at bay.

The findings, published in the journal Science, push the earliest record of human-constructed bedding back by at least 100,000 years. Previously, notes George Dvorsky for Gizmodo, the oldest known specimen was 77,000-year-old grass bedding found in Sibudu, South Africa.

Humans inhabited the Border Cave, so named because it sits near the border of South Africa and eSwatini (formerly known as Swaziland), sporadically between 227,000 and 1,000 years ago. More recently, the site has yielded an array of significant archaeological finds related to these early residents.

Lead author Lyn Wadley, an archaeologist at the University of Witwatersrand in South Africa, tells Gizmodo that excavations at the cave revealed “ephemeral fossilized grass.” She says the layer of grass was probably at least a foot thick and “would have been as comfortable as any camp bed or haystack.”

Wadley and her colleagues used scanning electron microscopes and infrared spectroscopy to identify fossilized plant materials. In addition to broad-leafed grasses, the team found traces of burned camphor bush, which is still used by people in rural East Africa as an aerial insect repellent, reports Ashley Strickland for CNN.

The Border Cave rock shelter in the Lebombo Mountains of South Africa

Because the ash is thought to have come from the same grass used in the bedding, the researchers suggest that Border Cave’s occupants periodically burned and replaced their mats with fresh plant matter. Per the paper, the ash repelled crawling insects by blocking “their breathing and biting apparatus and eventually [leaving] them dehydrated.”

Wadley says the findings are indicative of considerable sophistication on the part of early humans.

“Through the use of ash and medicinal plants to repel insects, we realize that they had some pharmacological knowledge,” she explains.

“Furthermore, they could extend their stay at favoured campsites by planning ahead and cleaning them through burning fusty beds. They therefore had some basic knowledge of health care through practising hygiene.”

Mixed in with the bedding, the team found ocher particles and flakes of stone possibly chipped off during toolmaking. The slivers of rock may indicate that the soft bedding was used as a seat for daily chores, while the red pigment may have rubbed off of individuals’ skin or other Stone Age canvases.

The researchers can’t be absolutely certain that ancient humans slept on the grass bedding. But Javier Baena Preysler, an archaeologist at the Autonomous University of Madrid who was not involved in the study, tells Science that this is the “most plausible interpretation.”

To estimate the proposed bedding’s age, Wadley and her team conducted radiocarbon testing on a pair of teeth discovered in the same strata of the cave’s sediments.

Speaking with Science, Dani Nadel, an archaeologist at the University of Haifa who was not involved in the research, deems this methodology “a bit shaky.” He points out that relying on just two teeth rather than analysis of the actual plant remnants could have yielded inaccurate dates.

Since the final layer of plant bedding was left unburned, the archaeologists suggest that the humans who had once lined the Border Cave’s floor with soft, green grass eventually abandoned the site.