Scientists unearthed the earliest evidence of modern humans in Europe

Humans have a gift for moving into new places and coopting them for themselves. According to new research, this long-held tradition includes arriving in Europe from Africa thousands of years earlier than previously thought.

A pair of studies published Monday describes the earliest evidence of humans in Europe. They suggest that as many as 45,000 years ago, anatomically modern humans arrived just as Neanderthal populations began to decline. Neanderthals disappeared around 40,000 years ago — although they live on in our DNA today.

In the papers, scientists describe human remains, including one tooth, collected at Bacho Kiro Cave in central Bulgaria. Among the remains, scientists also found ornaments including two pierced bear tooth pendants, as well as other tools and fragments of hunted animals.

The team approximates that the findings date from between 46,940 and 42,616 years ago. That period represents the Middle to Upper Paleolithic transition. This is when Neanderthals began to die off, only to be replaced by humans

It's likely these bones belonged to some of the first anatomically modern humans in Europe. The fact that they were also found with ornaments displays an ancient example of the intermixing of human and Neanderthal culture.

Taken together, this suggests anatomically modern humans and Neanderthals had ample amounts of time to interact, which is a confirmation of previous thinking about the two groups, but also might be a factor in their mutual enrichment,

The human remains are described in Nature Ecology & Evolution while the artifacts are described in Nature.

The first humans in Europe – The Nature Ecology & Evolution paper deals directly with dating the remains found in the Bacho Kiro Cave.

The Bacho Kiro Cave is far more than a single alcove: It stretches through a little over 2 miles and forms four floors of caverns — an earthly carving created by an underground river. In 2015, scientists re-excavated this site in order to search for evidence of ancient humans, but it's been a tourist destination since 1937.

The bulk of the analysis of these remains was done in the lab, where scientists used DNA sequencing and radiocarbon dating techniques to approximate how old the bone fragments they uncovered actually were. The carbon dating placed them between 46,940 and 43,650 years old. The DNA dating techniques supported that carbon dating data, placing the remains between 44,830 to 42,616 years old.

Both of those dating methods helped bolster the case that these are actually the oldest anatomically modern human remains in Europe. Previously, some of the earliest evidence of human remains were found at Kent Cave in the United Kingdom, where a mandible excavated in 1927 turned out to be over 41,000 years old. Two teeth found in Italy pushed the date of human arrival in Europe back to between 43,000 and 45,000 years ago.

These findings, however, push the date window back to as early as 46,940 years ago — although a related commentary points out these estimates can be about 450 years off.

An extended period of intermixing– The Nature paper deals with the significance of the artifacts found alongside these human remains.

Even though the Neanderthals eventually died out, there's evidence that we did live side-by-side. Humans and Neanderthals interbred (we also got cozy with at least 4 other species in the Homo genus). During those trysts, Neanderthals passed on the ability to adapt to new viruses to their hybrid children.

Homo sapiens didn't just share genes and beds with Neanderthals. Our ancestors also shared rituals and tools. This study argues that these first human migrants to Europe passed on some jewelry tips to the Neanderthal in the form of bear tooth pendants.

The authors point out that these pendants resemble artifacts created by Neanderthals and excavated from the Grotte du Renne – a cave system in France where some of the last Neanderthals lived during the Middle and Upper Paleolithic period. These artifacts have been used to help bolster the argument that Neanderthals did at least create their jewelry and didn't, for instance, steal them from humans or simply die alongside the work of humans, leaving a confusing fossil record.

Those French artifacts prompted a more controversial point: whether the Neanderthals came up with the idea for these ornaments on their own or whether they were inspired by Homo sapiens.

These study authors argue that the very last Neanderthals produced the ornaments found in France because they were inspired by the humans who had arrived as early as 47,000 years ago. Pushing back the date of human arrival to Europe, they argue, solidifies the idea that Neanderthals may have drawn inspiration from humans.

That said, other evidence suggested that Neanderthals had more going on that we give them credit for. They buried their dead alongside flowers, made their own art, and had their own material culture.

How much of that culture comes down to intermixing with us remains to be seen. But if these first human travelers to land in Europe tell us anything, it's that humans and Neanderthals definitely overlapped long enough to influence each other in some ways.

Abstract, Nature Ecology & Evolution Paper: The stratigraphy at Bacho Kiro Cave, Bulgaria, spans the Middle to Upper Palaeolithic transition, including an Initial Upper Palaeolithic (IUP) assemblage argued to represent the earliest arrival of Upper Palaeolithic Homo sapiens in Europe. We applied the latest techniques in 14C dating to an extensive dataset of newly excavated animal and human bones to produce a robust, high-precision radiocarbon chronology for the site. At the base of the stratigraphy, the Middle Palaeolithic (MP) occupation dates to >51,000 yr bp. A chronological gap of over 3,000 years separates the MP occupation from the occupation of the cave by H. sapiens, which extends to 34,000 cal bp. The extensive IUP assemblage, now associated with directly dated H. sapiens fossils at this site, securely dates to 45,820–43,650 cal bp (95.4% probability), probably beginning from 46,940 cal bp (95.4% probability). The results provide chronological context for the early occupation of Europe by Upper Palaeolithic H. sapiens.

Abstract, Nature paper: The Middle to Upper Palaeolithic transition in Europe witnessed the replacement and partial absorption of local Neanderthal populations by Homo sapiens populations of African origin1 . However, this process probably varied across regions and its details remain largely unknown. In particular, the duration of chronological overlap between the two groups is much debated, as are the implications of this overlap for the nature of the biological and cultural interactions between Neanderthals and H. sapiens. Here we report the discovery and direct dating of human remains found in association with Initial Upper Palaeolithic artefacts2 , from excavations at Bacho Kiro Cave (Bulgaria). Morphological analysis of a tooth and mitochondrial DNA from several hominin bone fragments, identifed through proteomic screening, assign these finds to H. sapiens and link the expansion of Initial Upper Palaeolithic technologies with the spread of H. sapiens into the mid-latitudes of Eurasia before 45 thousand years ago3 . The excavations yielded a wealth of bone artefacts, including pendants manufactured from cave bear teeth that are reminiscent of those later produced by the last Neanderthals of western Europe4–6 . These finds are consistent with models based on the arrival of multiple waves of H. sapiens into Europe coming into contact with declining Neanderthal populations