Neanderthals and Early Humans Hung Out Way More Than We Thought, Study Finds

A team’s investigation of ancient human burials in Israel’s Tinshemet Cave has revealed evidence that Homo sapiens and our nearest cousins, the Neanderthals, intermingled in ancient times, sharing moments of daily life and various customs.

The team’s research—published today in Nature Human Behavior—investigated stone tools, hunting strategies, and social aspects of the two human groups, and found they were much more intertwined in the area than previously believed.

“Neanderthal and Homo sapiens are sister populations,” said Israel Hershkovitz, an anthropologist at Tel Aviv University and co-author of the study, in an email to Gizmodo. “Biologically, they are not different species; Morphologically, they are. The two groups interbreed throughout the Middle Paleolithic.”

Neanderthals (Homo neanderthalensis) were a group of humans who interbred with anatomically modern humans (Homo sapiens) but looked fairly different, with barrel chests, stocky frames, and pronounced brows.

Late last year, landmark studies in Nature and Science constrained the time frame of some of the earliest Homo sapiens interbreeding with Neanderthals in Europe, based on analysis of hundreds of genomes. The new research indicates that the two groups may have interacted even earlier in the Levant.

“Instead of killing each other and competing for food resources, they managed to share knowledge and technology (and, of course, genes) to the level that their habitation sites are indistinguishable,” Hershkovitz added.

In 2021, Hershkovitz was part of a team that studied roughly 120,000-year-old hominin bones that they found were not quite Homo sapiens—but not quite Neanderthal, either. The archaic hominin fragments—a skull, a mandible and teeth—from the Nesher Ramla site complicated a relatively straightforward evolutionary picture of humankind, in which either Neanderthals or Homo sapiens exclusively occupied the Levant.

The Nesher Ramla Homo, as the ambiguous human group is now known, indicated to the team that there was more interaction between the two human species than previously known, though not everyone agrees. More specific dating of the fossil remains would help nail down the identity of the fossil remains and the timeline of human expansion and occupation of the Levant and beyond. Regardless, the new paper further muddies the waters, saying that genetically distinct groups of Homo sapiens, Neanderthals, or a bit of both may have overlapped to the extent that their cultural products, hunting methods, and social structures were homogenized, if not practically indistinguishable.

Hershkovitz added that a handful of questions remain outstanding, including what happened to the early Homo sapiens at nearby sites (including the famous site of Qazfeh), the timing of the first encounters between the Nesher Ramla humans and Homo sapiens, and what the cadence of human migration was out of Africa.

“These strata broadly share a uniform lithic [stone] technology, the use of ochre, a large-ungulate hunting pattern, the presence of articulated human remains and the presence of grave goods or non-utilitarian artefacts,” the team wrote, concluding that the uniform cultural aspects across the sites “could be a result of intensifying social interactions and admixture among African H. sapiens and Eurasian Neanderthal-like hominins in the mid-MP Levant.”

Moreover, Hershkovitz added, it remains a possibility that the Nesher Ramla individuals were the ancestors of the Neanderthals that paleoanthropologists find across Europe, those who disappear from the fossil record about 40,000 years ago.

Neanderthals are generally thought not to have gone extinct, but to have been subsumed into anatomically modern human populations. Neanderthal DNA persists in our genetics today, and even some human traits are associated with our closest human relatives.