What Is Going On With Neanderthals?
Summarising the last year of surprising Neanderthal research and results
When it comes to rapid advances in archaeological knowledge, almost no area other than the Eurasian bronze age has moved faster than the Neanderthals. Barely a decade ago it was considered heresy to argue that we Homo sapiens intermixed with our elder cousins, now we have entire genomes to play with, and the stories they are telling continue to surprise.
So here are some of the key findings from the past 12 months.
Increasing Evidence of Advanced Cognitive Abilities
I wrote a brief overview several years ago on Neanderthal’s abilities to make fire and use fire to distill tar and perform other functions:
Neanderthal handaxes, those large pear-shaped flint tools, characteristic of their species, have been analysed closely under microscopes and many display a pattern of scratches and striations which look very similar to flint tools striking against iron pyrites (‘fool’s gold’). This combination has been well documented ethnographically, which is not a surprise since pyrite striking on flint produces a visible spark. Other evidence for Neanderthal fire skills come from well-preserved wooden spears, where the points have been fire-hardened, as well as from their careful selection of firewood, as attested from Abric Romaní in Spain. But probably the best display of fire technology comes from the Neanderthal production of glues - specifically tar created from heating birch-bark. This procedure can only be done at a certain temperature and oxygen has to be excluded from the process, indicating that Neanderthals had a fine-tuned mastery of heat.
In November 2024 a paper published in Quaternary Science Reviews presented evidence from Gibraltar for Neanderthals' control of "anoxic heating," a complex process used to produce tar as an adhesive for tool-making. This technique involved carefully managed heating of buried wood to extract some kind of resin without combustion. The kiln they seemed to have built used a mix of sand and guano to create a thermally favourable wall which allowed heat from a fire to distill the tar from the plants/wood, without burning it in the process. All of this points to their cognitive abilities for understanding material properties, constructing and conducting multi-stage technological processes and communicating effectively between themselves and between generations. It seems unlikely that they could have built an oxygen-free kiln which needed to be heated to within a certain temperature band, if they didn’t have full use of complex language and mental processes of imagination and planning.
Discovery of a Unique Neanderthal Lineage
Whilst I covered this finding in more detail in an earlier post, it is worth repeating that genetic analysis of older Neanderthal fossils revealed a completely isolated and unexpected sub-population.
The Neanderthal individual was named "Thorin," whose remains were discovered in the Mandrin cave in France. Genetic analysis indicated that Thorin's lineage diverged from the main Neanderthal population around 103,000 years ago, suggesting prolonged isolation and inbreeding within this group - likely around 50,000 years of separation from their neighbours. We can expect to see similar patterns of small groups maintaining their distance from other Neanderthals in future studies, which points to some deep behavioural differences between them and us modern humans.
A New Timeline For Interbreeding?
Two papers both published in December 2024 have substantially tightened up the timeline for human-Neanderthal intermixing, with some radical implications for the rest of global archaeology. The two papers are:
Neanderthal ancestry through time: Insights from genomes of ancient and present-day humans
Earliest modern human genomes constrain timing of Neanderthal admixture
These both deserve a more comprehensive analysis, but the main takeaway points are these - by sequencing fossil human and Neanderthal genomes from Oase, Ust’-Ishim, Zlatý kůň, Ilsenhöhle and Bacho Kiro, researchers have narrowed down the interbreeding window to between 45 and 49,000 years ago. Outside of sub-Saharan Africa, all human groups show the genetic signature of this interbreeding event, which means that we non-Africans are all descended from this modern human population. The exciting part here is that we have archaeological evidence of human activity in other parts of the world that pre-date this, including 65,000 years old site evidence from Madjedbebe, Australia, and 51,000 year old rock art from Sulawesi. This means that:
Ranis genomes harbour Neanderthal segments that originate from a single admixture event shared with all non-Africans that we date to approximately 45,000–49,000 years ago. This implies that ancestors of all non-Africans sequenced so far resided in a common population at this time, and further suggests that modern human remains older than 50,000 years from outside Africa represent different non-African populations.
The implications of this for Asian and Australian archaeology are profound. As long time readers know, I have been interested in the question of when modern humans arrived in Australia for a long time, and these results suggest that multiple different populations may have settled that continent.
Neanderthal bottleneck?
The question of whether Neanderthals experienced a genetic bottleneck was re-opened with a new 2025 paper looking at the inner ear bones of pre-Neanderthals at the site of Sima de los Huesos and then later Neanderthals. The expectation was that an early bottleneck around 400,000 years ago would show up as a reduction of bone structure diversity.
The results actually pointed to a later bottleneck:
Our study suggests that there was a late bottleneck event in the evolution of the Neanderthal clade, as demonstrated by the significantly lower morphological variation in late Neanderthals relative to Krapina and (less so) Sima de los Huesos populations. This is further evidenced by the fact that late Neanderthals have a significantly lower variation even when compared to modern humans—thus providing strong support to Scenario #3 that an abrupt and marked reduction in the population, and associated phenotypic and, likely, genetic diversity, occurred after the currently accepted date for the Krapina sample (130–120 ka103). The evidence for a late-occurring reduction in genetic and phenotypic variation also eliminates Scenario #1, which posited the absence of any bottleneck event occurring in the evolution of the Neanderthal clade.
This timing supports the earlier paper about the Thorin lineage, which was one of several groups that had diverged from one another around 100,000 years ago. Oddly the climatic change during this period, the MIS 5 interglacial period, increased temperatures and the possibility of movement and hunting further afield. Other genetic work suggests that the bottleneck could have been caused by a population turnover rather than contraction through severe weather conditions.
Altogether then we have new results on Neanderthal group structures, population structures, interbreeding with modern humans and cognitive capacities - all pointing towards a much more interesting story, full of dynamic group interactions and a much firmer time limit on human mixing. Genetic results from Croatian and German palaeolithic fossils may end up affecting modern Australian and Oceanic archaeology, but that is a story for another day!
I'm taking a linguistics course right now just wrote something about the etymology of the word Neanderthal. Maybe someone here will be interested:
The word Neanderthal comes from the name of the Neander Valley in Germany, which in turn is named for a 17th century German songwriter named Joachim Neander. His surname is of Greek orgin, derived from neos (νέος, meaning "new") and andros (ἀνδρός, meaning "man"). So, Neander essentially means "new man."
In 1856, human fossils were discovered in the Neanderthal by workers at a limestone quarry. The fossils were found in a deep, undisturbed cave deposit, and were therefore assumed to be of great antiquity.
The main difference between the fossils found in Neanderthal was that the skull had notable differences with the skulls of other ancient skeletons. For an example, they featured an extremely pronounced brow ridge. This led researchers to propose that the fossils were remains not of prehistoric humans, but of a previously-unknown species of bipedal big-brained apes.
By the early 1900s, the word Neanderthal had entered popular speech, signifying a stupid, brutish person. In the popular imagination, the word neanderthal referred to subhuman cavemen who communicated through grunts.
Formerly, it was believed that Neanderthals were non-humans, and the idea that they might have interbred with ancient humans was considered heretical. In 2013, however, geneticists announced that they had proven that Neanderthals interbred with ancient humans. In other words, they were the same species.
Over the course of the past decade, announcements about new scientific discoveries have been coming at a breakneck pace.
It is perhaps worth noting that the German pronunciation is /ˈneː.andɐˌtaːl/. Formerly, the word was written as "neanderthal", with a silent th. German spelling reforms have since eliminated the silent h, meaning that the word is now spelled "neandertal".
In English, the older spelling is still preferred, and the word is commonly pronounced as /niˈændɚˌθɔl/, with the dental fricative /θ/ representing the alveolar stop /t/. This is an interesting example of how orthography can effect pronunciation.
In summary, the word neanderthal literally means "Neander Valley" when directly translated into English. Both the pronunciation and spelling of the English word are inconsistent with German. The popular conception of the word is based on an outdated misconception about the intellectual abilities of prehistoric humans.
It will be interesting to see how the meaning of the word neanderthal will evolve in the future. Now that we know that modern human are descended from neanderthals, will our language continue to exhibit anti-neanderthal prejudice?
I note that this discussion and the cited sources only look at introgression of NEA material into AMH populations. <a href="https://www.researchgate.net/publication/318203664_Deeply_divergent_archaic_mitochondrial_genome_provides_lower_time_boundary_for_African_gene_flow_into_Neanderthals">Posth et al. (2017)</a> show that introgression of AMH mtDNA material was demonstrated by ~100kya, no earlier than ~270kya, and the discussion of admixture should be considered from both directions to inform understanding of AMH interactions in Eurasia with NEA populations, as looking only at such samples as we have of AMH are misleading due to the paucity of source material. In addition, <a href="https://www.science.org/doi/10.1126/science.abb6460">Petr et al. (2020)</a> showed that NEA Y DNA was wholly replaced by AMH material after ~370kya.
>"The phylogenetic relationships of archaic and modern human Y chromosomes differ from the population relationships inferred from the autosomal genomes and mirror mitochondrial DNA phylogenies, indicating replacement of both the mitochondrial and Y chromosomal gene pools in late Neanderthals...the young TMRCA of Neanderthal and modern human Y chromosomes and mtDNAs suggest that these loci have been replaced in Neanderthals through gene flow from an early lineage closely related to modern humans"
These papers show that long before AMH samples presently available provide sources of evidence of admixture and interactions between AMH and other human species in Eurasia, AMH have been present and interacting with other human species outside of Africa, because there is no other way for NEA mtDNA and Y DNA to have been replaced by AMH material by ~100kya, and sequencing of NEA samples show that to have occurred no later than that time. Therefore the few AMH samples we have, none of which represent the earlier presence of AMH in Eurasia, are inadequate to fully reveal interspecific interactions of AMH in Eurasia.
Conclusions are of limited value due to a lack of samples availing us glimpses of processes that were ongoing, but for which we have only few sources of evidence. Regarding presence or absence of AMH in Eurasia, and for reproductive interactions with other human species, it is necessary to consider both directions of gene flow to gain the full breadth of evidence from samples available. Indeed, while funding is availed papers that support the OoA hypothesis, evidence of gene flow suggests a long duration of interspecific interactions that could not have occurred in Africa, as NEA have never been shown to have lived in Africa, for which only limited funding is available to research.
Thanks!