Human Origins Icon Human Origins
Paleontology Icon Paleontology

Fossil Friday: New Evidence for the Human Nature of Neanderthals

Photo credit: AquilaGib, CC BY-SA 3.0 , via Wikimedia Commons.

The reconstruction of Neanderthal appearance and behavior has quite a checkered history. After an initial controversy over whether the fossils really represent ancient humans or just malformed modern humans, Neanderthals were described in 1864 as distinct hominin species, Homo neanderthalensis. For a long time they were considered as brutish cavemen with a club and almost gorilla-like appearance. Then the scientific opinion shifted and Neanderthals were more and more recognized as human-like and even as geniuses of the ice age (Husemann 2005Finlayson 2019), based on an avalanche of new evidence for complex human behavior (Nowell 2023Vernimmen 2023). We now know that Neanderthals used fire (Angelucci et al. 2023), buried their dead (Balzeau et al. 2020Dockdrill 2020), created stone circles (Jaubert et al. 2016Callaway 2016) and bone tools (Soressi et al. 2013), made jewellery from eagle talons (Radovčić et al. 2015Rodríguez-Hidalgo et al. 2019) and used feathers as body decoration (Peresani et al. 2011Finlayson et al. 2012), made cave art with paintings and engravings (Rodríguez-Vidal et al. 2014Hoffmann et al. 2018aMarquet et al. 2023), played music with bone flutes (Turk et al. 2018), used ochre as pigment (Roebroeks et al. 2012Hoffmann et al. 2018b) and sophisticated fibre technology (Hardy et al. 2020), produced flour from processed plants (Mariotti Lippi et al. 2023), dived for seafood (Villa et al. 2020), cooked food and self-medicated with herbal painkillers and antibiotics (Hardy et al. 2012Weyrich et al. 2017), and even produced glue from birch bark with a complex chemical procedure (Blessing & Schmidt 2021Schmidt et al. 2023).

New Anatomic Data

But it is not just new evidence for Neanderthal behavior that overturned our previous crude image of Neanderthals as dumb brutes, but also new anatomic data. Contrary to earlier beliefs, more recent studies have demonstrated a fully upright posture with typical human spinal curvature called lordosis (Haeusler et al. 2019). The latter authors concluded that ”after more than a century of alternative views, it should be apparent that there is nothing in Neandertal pelvic or vertebral morphology that rejects their possession of spinal curvatures well within the ranges of variation of healthy recent humans.” There even exists compelling new evidence for hearing and speech capacities (Conde-Valverde et al. 2021), which “demonstrates that the Neanderthals possessed a communication system that was as complex and efficient as modern human speech” (Starr 2021).

Correlated with this fundamental rethinking of Neanderthals (Nowell 2023) in terms of their anatomy, culture, and mental capabilities, their classification has also changed over time. At first they were considered as a different species, Homo neanderthalensis, then they were just considered as a subspecies of modern humans, Homo sapiens, and since the late 1990s again as “an unambiguously demarcated morphospecies” (Tattersall & Schwartz 2006; also see Harvati et al. 2004Márquez et al. 2014, and Wynn et al. 2016). The new field of paleogenomics brought insight into their DNA (Green et al. 2010), which was considered as sufficiently dissimilar to warrant a separate species status again (Clarke 2016), even though there was also evidence for hybridization and genetic admixture with modern humans (Meneganzin & Bernardi 2023). Paleogeneticist and Nobel laureate Svante Pääbo (2014) called the controversy of the species status of Neanderthals as unresolvable, because of the arbitrariness and fuzziness of species concepts (also see Meneganzin & Bernardi 2023Nowell 2023, and Stringer 2023). The controversy still continues as is evident from a recent article titled “Are Neanderthals and Homo sapiens the same species?” (Heidt 2023), which discusses the fact that “scientists have been vollying the question back and forth for more than a century”. Nowell (2023) wrote: “From their initial discovery until today, Neandertals have shifted between “being recognized as human or being pushed to the constitutive outside of humanness,” what Drell (2000, p. 15) describes as “the oscillating dichotomy of Same and Other.”

Of course, the undeniable evidence for significant and common genetic admixture (Kuhlwilm et al. 2016Villanea & Schraiber 2019Callaway 2021), which makes up 1-4 percent of the modern human genome (Reilly et al. 2022), would suggest that Neanderthals and modern humans shared a common gene pool and belonged to the same biospecies. Even the skeptic and ID opponent Michael Shermer (2010) agreed in an article for Scientific American that the genomic evidence suggests that our Neanderthal brethren were not a separate species. Strong reproductive isolation barriers that limited the amount of introgression were proposed by Overmann & Coolidge (2013), but many experts remain unconvinced. Paleoanthropologist Bence Viola from the University of Toronto said (quoted in Vernimmen 2023): “Homo sapiens clearly recognized Neanderthals as mating partners, which suggests they thought of them as humans — maybe ‘the weird guys living behind the mountains,’ but still, fellow humans.”

But what do we make of the anatomical differences between Neanderthals and modern humans? Don’t they support a separate species status? Actually, this would not follow even if the differences lay outside the range of variability of modern humans, because that is also the case in many other subspecies of living animals. However, some human populations such as Australian aboriginals indeed share with archaic humans like Neanderthals a robust skull with pronounced brow ridges, which lead Darwin’s bulldog, Thomas Huxley (in Lyell 1863), to compare them with Neanderthals. Of course this also had some typical Darwinist racist connotations. Just like Neanderthals, native Australians were considered primitive and inferior. Nevertheless, the similarities are real and have been confirmed by modern anatomical studies (e.g., Wolpoff & Caspari 1996), which concluded that “the interpretation of Neanderthals as a different species is very unlikely.” Anatomical and cognitive differences between Neanderthals and anatomically modern humans were also affirmed by Wynn et al. (2016), who nevertheless emphatically rejected labeling these differences as implying inferiority or superiority. More recent research even suggests that the characteristic skull features may rather be based on phenotypic plasticity than an evolutionary heritage from ape-like ancestors (Curnoe 2011).

Why So Much Debate?

So, why is there still so much debate and controversy about the species status of Neanderthals? Well, what is at stake is not just some esoteric species problem in the scientific ivory tower of a few paleoanthropologists, but the very question of human nature and human uniqueness, thus what it even means to be human. The recognition of Neanderthals as a distinct species would make the uncanny valley a bit shallower, as Peeters & Zwart (2020) put it, and would challenge “longstanding ideas about the uniqueness of our species” (Seghers 2018). A so-called multiple species model was proposed for the origin of behavioral modernity (Moro Abadía & González Morales 2010). Even mainstream evolutionary biologists recognize that this is a “politically charged context” (Nowell 2023), and thus certainly subject to bias when you approach this question from either a Darwinist viewpoint of modern materialist and atheist science, or from the Judeo-Christian viewpoint of human exceptionalism, where humans are made in the image of God.

In my humble opinion, the evidence for symbolic thinking, language, and genetic admixture clearly suggests that Neanderthals belong to our very own species. They were no inhabitants of the uncanny valley of objects that just resemble humans (think of Sophia the robot or CGI characters), but they are fully human and should again be classified as Homo sapiens neanderthalensis. The latest technical literature shows that such a view is well rooted in up-to-date mainstream science. McCrae (2023) concluded, in an article titled “Neanderthals might not be the separate species we always thought,” that even though “it’s unlikely we’ll finally see the classification of Homo neanderthalensis fade into obscurity any time soon. … Still, as more sibling than cousin, it seems the poor old Neanderthal deserves to sit right by our side in the Homo sapien[s] family portrait.”