Neanderthal

For other uses, see Neanderthal (disambiguation).

For Neanderthals and other related species in popular culture, see Caveman.

Neanderthal Temporal range: Middle to Late Pleistocene
An approximate reconstruction of a Neanderthal skeleton. The central rib-cage (including the sternum) and parts of the pelvis are from modern humans.
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Primates
Suborder:	Haplorhini
Infraorder:	Simiiformes
Family:	Hominidae
Subfamily:	Homininae
Tribe:	Hominini
Genus:	Homo
Species:	†H. neanderthalensis
Binomial name
†Homo neanderthalensis King, 1864
Known Neanderthal range in Europe (blue), Southwest Asia (orange), Uzbekistan (green), and the Altai Mountains (violet). Possible total range shown by dashed line
Synonyms
Homo H. stupidus Haeckel, 1895 H. europaeus primigenius Wilser, 1898 H. primigenius Schwalbe, 1906 H. antiquus Adloff, 1908 H. transprimigenius mousteriensis Farrer, 1908 H. mousteriensis hauseri Klaatsch 1909 H. priscus Krause, 1909 H. chapellensis von Buttel-Reepen, 1911 H. calpicus Keith, 1911 H. acheulensis moustieri Wiegers, 1915 H. lemousteriensis Wiegers, 1915 H. naulettensis Baudouin, 1916 H. sapiens neanderthalensis Kleinshmidt, 1922 H. heringsdorfensis Werthe, 1928 H. galilensis Joleaud, 1931 H. primigenius galilaeensis Sklerj, 1937 H. kiikobiensis Bontsch-Osmolovskii, 1940 H. sapiens krapinensis Campbell, 1962 H. erectus mapaensis Kurth, 1965 Palaeoanthropus P. neanderthalensis McCown and Keith, 1939 P. heidelbergensis McCown and Keith, 1939 P. ehringsdorfensis Paterson, 1940 P. krapinensis Sergi, 1911 P. palestinensis McCown and Keith, 1939 P. europaeus Sergi, 1910 Protanthropus P. atavus Haeckel, 1895 P. tabunensis Bonarelli, 1944 Acanthropus A. neanderthalensis Arldt, 1915 A. primigenius Abel, 1920 A. neanderthalensis Dawkins, 1926

Neanderthals (/niˈændərˌtɑːl, neɪ-, -ˌθɑːl/ nee-AN-də(r)-TAHL, nay-, -⁠THAHL; Homo neanderthalensis or H. sapiens neanderthalensis) are an extinct group of archaic humans (generally regarded as a distinct species, though some regard it as a subspecies of Homo sapiens) who lived in Eurasia until about 40,000 years ago. The type specimen, Neanderthal 1, was found in 1856 in the Neander Valley in present-day Germany.

It is not clear when the line of Neanderthals split from that of modern humans; studies have produced various times ranging from 315,000 to more than 800,000 years ago. The date of divergence of Neanderthals from their ancestor H. heidelbergensis is also unclear. The oldest potential Neanderthal bones date to 430,000 years ago, but the classification remains uncertain. Neanderthals are known from numerous fossils, especially from after 130,000 years ago. The reasons for Neanderthal extinction are disputed.

Neanderthals lived in a high-stress environment with high trauma rates; about 80% of Neanderthal individuals died before the age of 40. The total population of Neanderthals remained low, and interbreeding with modern humans tended toward a loss of Neanderthal genes over time. They lacked effective long-distance networks. Despite this, there is evidence of regional cultures and regular communication between communities, possibly moving between caves seasonally. For much of the early 20th century, European researchers depicted Neanderthals as primitive, unintelligent and brutish. Although knowledge and perception of them has markedly changed since then in the scientific community, the image of the unevolved caveman archetype remains prevalent in popular culture.

Compared with modern humans, Neanderthals had a more robust build and proportionally shorter limbs. Researchers often explain these features as adaptations to conserve heat in a cold climate; however, they may also have been adaptations for sprinting in the warmer, forested landscape that Neanderthals often inhabited. They had cold-specific adaptations, such as specialised body-fat storage. Average Neanderthal men stood around 165 cm (5 ft 5 in) and women 153 cm (5 ft 0 in) tall, similar to pre-industrial modern Europeans. The braincases of Neanderthal men and women averaged about 1,600 cm³ (98 cu in) and 1,300 cm³ (79 cu in), respectively, which is considerably larger than the modern human average. Although they were probably apex predators, they still competed with cave lions, cave hyenas and other large predators. A number of examples of symbolic thought and Palaeolithic art have been inconclusively attributed to Neanderthals. Some claims of religious beliefs have been made. Neanderthals were likely capable of speech, possibly articulate, although the complexity of their language is not known.

The 2010 Neanderthal genome project's draft report presented evidence for interbreeding between Neanderthals and modern humans. Neanderthals also appear to have interbred with Denisovans, a different group of archaic humans, in Siberia. Around 1–4% of genomes of Eurasians, Indigenous Australians, Melanesians, Native Americans and North Africans is of Neanderthal ancestry, while most inhabitants of sub-Saharan Africa have around 0.3% of Neanderthal genes, save possible traces from early sapiens-to-Neanderthal gene flow and/or more recent back-migration of Eurasians to Africa. In all, about 20% of distinctly Neanderthal gene variants survive in modern humans. Neanderthal introgression appears to have affected the modern human immune system, and is also implicated in several other biological functions and structures.

Taxonomy

See also: Human taxonomy

Etymology

The site of Kleine Feldhofer Grotte where Neanderthal 1 was discovered

Neanderthals are named after the Neander Valley in which the first identified specimen was found. The valley was spelled Neanderthal and the species was spelled Neanderthaler in German until the spelling reform of 1901. The spelling Neandertal for the species is occasionally seen in English, even in scientific publications, but the scientific name, H. neanderthalensis, is always spelled with th according to the principle of priority. The vernacular name of the species in German is always Neandertaler ("inhabitant of the Neander Valley"), whereas Neandertal always refers to the valley. The valley itself was named after the late 17th century German theologian and hymn writer Joachim Neander, who often visited the area. His name in turn means 'new man', being a learned Graecisation of the German surname Neumann.

Neanderthal can be pronounced using the /t/ (as in /niˈændərtɑːl/) or the standard English pronunciation of th with the fricative /θ/ (as /niˈændərθɔːl/). The latter pronunciation, nevertheless, has no basis in the original German word which is pronounced always with a t regardless of the historical spelling.

Neanderthal 1, the type specimen, was known as the "Neanderthal cranium" or "Neanderthal skull" in anthropological literature, and the individual reconstructed on the basis of the skull was occasionally called "the Neanderthal man". The binomial name Homo neanderthalensis—extending the name "Neanderthal man" from the individual specimen to the entire species, and formally recognising it as distinct from humans—was first proposed by Irish geologist William King in a paper read to the 33rd British Science Association in 1863. However, in 1864, he recommended that Neanderthals and modern humans be classified in different genera as he compared the Neanderthal braincase to that of a chimpanzee and argued that they were "incapable of moral and [theistic] conceptions".

Research history

Skullcap of Neanderthal 1, the type specimen, at the Musée de l'Homme, Paris

Ernst Haeckel's Primate family tree showing H. stupidus (Neanderthal) as the ancestor to H. sapiens

The first Neanderthal remains—Engis 2 (a skull)—were discovered in 1829 by Dutch/Belgian prehistorian Philippe-Charles Schmerling in the Grottes d'Engis, Belgium. He concluded that these "poorly developed" human remains must have been buried at the same time and by the same causes as the co-existing remains of extinct animal species. In 1848, Gibraltar 1 from Forbes' Quarry was presented to the Gibraltar Scientific Society by their Secretary Lieutenant Edmund Henry Réné Flint, but was thought to be a modern human skull. In 1856, local schoolteacher Johann Carl Fuhlrott recognised bones from Kleine Feldhofer Grotte in Neander Valley—Neanderthal 1 (the holotype specimen)—as distinct from modern humans, and gave them to German anthropologist Hermann Schaaffhausen to study in 1857. It comprised the cranium, thigh bones, right arm, left humerus and ulna, left ilium (hip bone), part of the right shoulder blade, and pieces of the ribs.

Following Charles Darwin's On the Origin of Species, Fuhlrott and Schaaffhausen argued that the bones represented an archaic human form. Schaaffhausen, a social Darwinist, believed that humans linearly progressed from savage to civilised, and he concluded that Neanderthals were barbarous cave-dwellers. Fuhlrott and Schaaffhausen met opposition namely from the prolific pathologist Rudolf Virchow who argued against defining new species based on only a single find. In 1872, Virchow erroneously interpreted Neanderthal characteristics as evidence of senility, disease and malformation instead of archaicness, which stalled Neanderthal research until the end of the century.

By the early 20th century, numerous other Neanderthal discoveries were made, establishing H. neanderthalensis as a legitimate species. The most influential specimen was La Chapelle-aux-Saints 1 ("The Old Man") from La Chapelle-aux-Saints, France. French palaeontologist Marcellin Boule authored several publications, among the first to establish palaeontology as a science, detailing the specimen, but reconstructed him as slouching, ape-like, and only remotely related to modern humans.

The 1912 'discovery' of Piltdown Man (a hoax), appearing much more similar to modern humans than Neanderthals, was used as evidence that multiple different and unrelated branches of primitive humans existed, and supported Boule's reconstruction of H. neanderthalensis as a far distant relative and an evolutionary dead-end. He fuelled the popular image of Neanderthals as barbarous, slouching, club-wielding primitives; this image was reproduced for several decades and popularised in science fiction works, such as the 1911 The Quest for Fire by J.-H. Rosny aîné and the 1927 The Grisly Folk by H. G. Wells in which they are depicted as monsters. In 1911, Scottish anthropologist Arthur Keith reconstructed La Chapelle-aux-Saints 1 as an immediate precursor to modern humans, sitting next to a fire, producing tools, wearing a necklace, and having a more humanlike posture, but this failed to garner much scientific rapport, and Keith later abandoned his thesis in 1915.

By the middle of the century, based on the exposure of Piltdown Man as a hoax as well as a reexamination of La Chapelle-aux-Saints 1 (who had osteoarthritis which caused slouching in life) and new discoveries, the scientific community began to rework its understanding of Neanderthals. Ideas such as Neanderthal behaviour, intelligence and culture were being discussed, and a more humanlike image of them emerged. In 1939, American anthropologist Carleton Coon reconstructed a Neanderthal in a modern business suit and hat to emphasise that they would be, more or less, indistinguishable from modern humans had they survived into the present. William Golding's 1955 novel The Inheritors depicts Neanderthals as much more emotional and civilised. However, Boule's image continued to influence works until the 1960s. In modern-day, Neanderthal reconstructions are often very humanlike.

Hybridisation between Neanderthals and early modern humans had been suggested early on, such as by English anthropologist Thomas Huxley in 1890, Danish ethnographer Hans Peder Steensby in 1907, and Coon in 1962. In the early 2000s, supposed hybrid specimens were discovered: Lagar Velho 1 and Muierii 1. However, similar anatomy could also have been caused by adapting to a similar environment rather than interbreeding.

Neanderthal admixture was found to be present in modern populations in 2010 with the mapping of the first Neanderthal genome sequence. This was based on three specimens in Vindija Cave, Croatia, which contained almost 4% archaic DNA (allowing for near complete sequencing of the genome). However, there was approximately 1 error for every 200 letters (base pairs) based on the implausibly high mutation rate, probably due to the preservation of the sample. In 2012, British-American geneticist Graham Coop hypothesised that they instead found evidence of a different archaic human species interbreeding with modern humans, which was disproven in 2013 by the sequencing of a high-quality Neanderthal genome preserved in a toe bone from Denisova Cave, Siberia.

Classification

Homo sapiens Denisovan from Denisova Cave Denisovan from Baishiya Karst Cave Neanderthal from Denisova Cave Neanderthal from Sidrón Cave Neanderthal from Vindija Cave

2019 phylogeny based on comparison of ancient proteomes and genomes with those of modern species.

Neanderthals are hominids in the genus Homo, humans, and generally classified as a distinct species, H. neanderthalensis, although sometimes as a subspecies of modern human as Homo sapiens neanderthalensis. This would necessitate the classification of modern humans as H. sapiens sapiens.

A large part of the controversy stems from the vagueness of the term "species", as it is generally used to distinguish two genetically isolated populations, but admixture between modern humans and Neanderthals is known to have occurred. However, the absence of Neanderthal-derived patrilineal Y-chromosome and matrilineal mitochondrial DNA (mtDNA) in modern humans, along with the underrepresentation of Neanderthal X chromosome DNA, could imply reduced fertility or frequent sterility of some hybrid crosses, representing a partial biological reproductive barrier between the groups, and therefore species distinction. In 2014 geneticist Svante Pääbo summarised the controversy, describing such "taxonomic wars" as unresolvable, "since there is no definition of species perfectly describing the case".

Neanderthals are thought to have been more closely related to Denisovans than to modern humans. Likewise, Neanderthals and Denisovans share a more recent last common ancestor (LCA) than to modern humans, based on nuclear DNA (nDNA). However, Neanderthals and modern humans share a more recent mitochondrial LCA (observable by studying mtDNA) and Y chromosome LCA. This likely resulted from an interbreeding event subsequent to the Neanderthal/Denisovan split. This involved either introgression coming from an unknown archaic human into Denisovans, or introgression from an earlier unidentified modern human wave from Africa into Neanderthals. The fact that the mtDNA of a ~430,000 years old early Neanderthal-line archaic human from Sima de los Huesos in Spain is more closely related to those of Denisovans than to other Neanderthals or modern humans has been cited as evidence in favour of the latter hypothesis.

Evolution

Stage 1: early-pre-Neanderthal, possibly H. erectus (Tautavel Man, 450,000 years ago)

Stage 2: archaic Neanderthal, possibly H. heidelbergensis (Miguelón, 430,000 years ago)

Stage 3: early Neanderthal (Steinheim skull, 250,000 years ago)

Stage 4: classic European Neanderthal (La Chapelle-aux-Saints 1, 50,000 years ago)

It is largely thought that H. heidelbergensis was the last common ancestor of Neanderthals, Denisovans and modern humans before populations became isolated in Europe, Asia and Africa, respectively. The taxonomic distinction between H. heidelbergensis and Neanderthals is mostly based on a fossil gap in Europe between 300 and 243,000 years ago during marine isotope stage 8. "Neanderthals", by convention, are fossils which date to after this gap. DNA from archaic humans from the 430,000-year-old Sima de los Huesos site in Spain indicate that they are more closely related to Neanderthals than to Denisovans, indicating that the split between Neanderthals and Denisovans must predate this time. The 400,000-year-old Aroeira 3 skull may also represent an early member of the Neanderthal line. It is possible that gene flow between Western Europe and Africa during the Middle Pleistocene, may have obscured Neanderthal characteristics in some Middle Pleistocene European hominin specimens, such those from Ceprano, Italy, and Sićevo Gorge, Serbia. The fossil record is much more complete from 130,000 years ago onwards, and specimens from this period make up the bulk of known Neanderthal skeletons. Dental remains from the Italian Visogliano and Fontana Ranuccio sites indicate that Neanderthal dental features had evolved by around 450–430,000 years ago during the Middle Pleistocene.

There are two main hypotheses regarding the evolution of Neanderthals following the Neanderthal/human split: two-phase and accretion. Two-phase argues that a single major environmental event—such as the Saale glaciation—caused European H. heidelbergensis to increase rapidly in body size and robustness, as well as undergoing a lengthening of the head (phase 1), which then led to other changes in skull anatomy (phase 2). However, Neanderthal anatomy may not have been driven entirely by adapting to cold weather. Accretion holds that Neanderthals slowly evolved over time from the ancestral H. heidelbergensis, divided into four stages: early-pre-Neanderthals (MIS 12, Elster glaciation), pre-Neanderthals (MIS 11–9, Holstein interglacial), early Neanderthals (MIS 7–5, Saale glaciation–Eemian), and classic Neanderthals (MIS 4–3, Würm glaciation).

Numerous dates for the Neanderthal/human split have been suggested. The date of around 250,000 years ago cites "H. helmei" as being the last common ancestor (LCA), and the split is associated with the Levallois technique of making stone tools. The date of about 400,000 years ago uses H. heidelbergensis as the LCA. Estimates of 600,000 years ago assume that "H. rhodesiensis" was the LCA, which split off into modern human lineage and a Neanderthal/H. heidelbergensis lineage. Eight hundred thousand years ago has H. antecessor as the LCA, but different variations of this model would push the date back to 1 million years ago. However, a 2020 analysis of H. antecessor enamel proteomes suggests that H. antecessor is related but not a direct ancestor. DNA studies have yielded various results for the Neanderthal/human divergence time, such as 538–315, 553–321, 565–503, 654–475, 690–550, 765–550, 741–317, and 800–520,000 years ago; and a dental analysis concluded before 800,000 years ago.

Neanderthals and Denisovans are more closely related to each other than they are to modern humans, meaning the Neanderthal/Denisovan split occurred after their split with modern humans. Assuming a mutation rate of 1 × 10⁻⁹ or 0.5 × 10⁻⁹ per base pair (bp) per year, the Neanderthal/Denisovan split occurred around either 236–190,000 or 473–381,000 years ago, respectively. Using 1.1 × 10⁻⁸ per generation with a new generation every 29 years, the time is 744,000 years ago. Using 5 × 10⁻¹⁰ nucleotide sites per year, it is 616,000 years ago. Using the latter dates, the split had likely already occurred by the time hominins spread out across Europe, and unique Neanderthal features had begun evolving by 600–500,000 years ago. Before splitting, Neanderthal/Denisovans (or "Neandersovans") migrating out of Africa into Europe apparently interbred with an unidentified "superarchaic" human species who were already present there; these superarchaics were the descendants of a very early migration out of Africa around 1.9 mya.

Demographics

Further information: Neanderthals in Southwest Asia, Neanderthals in Gibraltar, and List of Neanderthal sites

Range

Neanderthal skull from Tabun Cave, Israel, at the Israel Museum

Pre- and early Neanderthals, living before the Last Interglacial (130–115,000 years ago), are poorly known and come mostly from Western European sites. From 130,000 years ago onwards, the quality of the fossil record increases dramatically with classic Neanderthals, who are recorded from Western, Central, Eastern and Mediterranean Europe, as well as Southwest, Central and Northern Asia up to the Altai Mountains in southern Siberia. Pre- and early Neanderthals, on the other hand, seem to have continuously occupied only France, Spain and Italy, although some appear to have moved out of this "core-area" to form temporary settlements eastward (although without leaving Europe). Nonetheless, southwestern France has the highest density of sites for pre-, early and classic Neanderthals. The Neanderthals were the first human species to permanently occupy Europe as the continent was only sporadically occupied by earlier humans.

The southernmost find was recorded at Shuqba Cave, Levant; reports of Neanderthals from the North African Jebel Irhoud and Haua Fteah have been reidentified as H. sapiens. Their easternmost presence is recorded at Denisova Cave, Siberia 85°E; the southeast Chinese Maba Man, a skull, shares several physical attributes with Neanderthals, although these may be the result of convergent evolution rather than Neanderthals extending their range to the Pacific Ocean. The northernmost bound is generally accepted to have been 55°N, with unambiguous sites known between 50–53°N, although this is difficult to assess because glacial advances destroy most human remains, and palaeoanthropologist Trine Kellberg Nielsen has argued that a lack of evidence of Southern Scandinavian occupation is (at least during the Last Interglacial) due to the former explanation and a lack of research in the area. Middle Palaeolithic artefacts have been found up to 60°N on the Russian plains, but these are more likely attributed to modern humans. A 2017 study claimed the presence of Homo at the 130,000-year-old Californian Cerutti Mastodon site in North America, but this is largely considered implausible.

It is unknown how the rapidly fluctuating climate of the last glacial period (Dansgaard–Oeschger events) impacted Neanderthals, as warming periods would produce more favourable temperatures but encourage forest growth and deter megafauna, whereas frigid periods would produce the opposite. However, Neanderthals may have preferred a forested landscape. Stable environments with mild mean annual temperatures may have been the most suitable Neanderthal habitats. Populations may have peaked in cold but not extreme intervals, such as marine isotope stages 8 and 6 (respectively, 300,000 and 191,000 years ago during the Saale glaciation). It is possible their range expanded and contracted as the ice retreated and grew, respectively, to avoid permafrost areas, residing in certain refuge zones during glacial maxima. In 2021, Israeli anthropologist Israel Hershkovitz and colleagues suggested the 140- to 120,000-year-old Israeli Nesher Ramla remains, which feature a mix of Neanderthal and more ancient H. erectus traits, represent one such source population which recolonised Europe following a glacial period.

Map of Europe during the Würm glaciation 70–20,000 years ago

Population

Like modern humans, Neanderthals probably descended from a very small population with an effective population—the number of individuals who can bear or father children—of 3,000 to 12,000 approximately. However, Neanderthals maintained this very low population, proliferating weakly harmful genes due to the reduced effectivity of natural selection. Various studies, using mtDNA analysis, yield varying effective populations, such as about 1,000 to 5,000; 5,000 to 9,000 remaining constant; or 3,000 to 25,000 steadily increasing until 52,000 years ago before declining until extinction. Archaeological evidence suggests that there was a tenfold increase in the modern human population in Western Europe during the period of the Neanderthal/modern human transition, and Neanderthals may have been at a demographic disadvantage due to a lower fertility rate, a higher infant mortality rate, or a combination of the two. Estimates giving a total population in the higher tens of thousands are contested. A consistently low population may be explained in the context of the "Boserupian Trap": a population's carrying capacity is limited by the amount of food it can obtain, which in turn is limited by its technology. Innovation increases with population, but if the population is too low, innovation will not occur very rapidly and the population will remain low. This is consistent with the apparent 150,000 year stagnation in Neanderthal lithic technology.

In a sample of 206 Neanderthals, based on the abundance of young and mature adults in comparison to other age demographics, about 80% of them above the age of 20 died before reaching 40. This high mortality rate was probably due to their high-stress environment. However, it has also been estimated that the age pyramids for Neanderthals and contemporary modern humans were the same. Infant mortality was estimated to have been very high for Neanderthals, about 43% in northern Eurasia.

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Locations of Neanderthal finds in Europe and the Levant.
View references

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Locations of Neanderthal finds in Eurasia (note, part of Spain is cut off)
View references

Anatomy

Main article: Neanderthal anatomy

Build

Comparisons of a modern Eurasian male example (left) and a Neanderthal (right) skull reconstruction at the Cleveland Museum of Natural History

Neanderthal skull features

Neanderthals had more robust and stockier builds than typical modern humans, wider and barrel-shaped rib cages; wider pelvises; and proportionally shorter forearms and forelegs.

Based on 45 Neanderthal long bones from 14 men and 7 women, the average height was 164 to 168 cm (5 ft 5 in to 5 ft 6 in) for males and 152 to 156 cm (5 ft 0 in to 5 ft 1 in) for females. For comparison, the average height of 20 males and 10 females Upper Palaeolithic humans is, respectively, 176.2 cm (5 ft 9.4 in) and 162.9 cm (5 ft 4.1 in), although this decreases by 10 cm (4 in) nearer the end of the period based on 21 males and 15 females; and the average in the year 1900 was 163 cm (5 ft 4 in) and 152.7 cm (5 ft 0 in), respectively. The fossil record shows that adult Neanderthals varied from about 147.5 to 177 cm (4 ft 10 in to 5 ft 10 in) in height, although some may have grown much taller (73.8 to 184.8 cm based on footprint length and from 65.8 to 189.3 cm based on footprint width). For Neanderthal weight, samples of 26 specimens found an average of 77.6 kg (171 lb) for males and 66.4 kg (146 lb) for females. Using 76 kg (168 lb), the body mass index for Neanderthal males was calculated to be 26.9–28.2, which in modern humans correlates to being overweight. This indicates a very robust build. The Neanderthal LEPR gene concerned with storing fat and body heat production is similar to that of the woolly mammoth, and so was likely an adaptation for cold climate.

Neanderthal hunters depicted in the Gallo-Roman Museum, Tongeren

The neck vertebrae of Neanderthals are thicker from the front to the rear and transversely than those of (most) modern humans, leading to stability, possibly to accommodate a different head shape and size. Although the Neanderthal thorax (where the ribcage is) was similar in size to modern humans, the longer and straighter ribs would have equated to a widened mid-lower thorax and stronger breathing in the lower thorax, which are indicative of a larger diaphragm and possibly greater lung capacity. The lung capacity of Kebara 2 was estimated to have been 9.04 L (2.39 US gal), compared to the average human capacity of 6 L (1.6 US gal) for males and 4.7 L (1.2 US gal) for females. The Neanderthal chest was also more pronounced (expanded front-to-back, or antero-posteriorly). The sacrum (where the pelvis connects to the spine) was more vertically inclined, and was placed lower in relation to the pelvis, causing the spine to be less curved (exhibit less lordosis) and to fold in on itself somewhat (to be invaginated). In modern populations, this condition affects just a proportion of the population, and is known as a lumbarised sacrum. Such modifications to the spine would have enhanced side-to-side (mediolateral) flexion, better supporting the wider lower thorax. It is claimed by some that this feature would be normal for all Homo, even tropically adapted Homo ergaster or erectus, with the condition of a narrower thorax in most modern humans being a unique characteristic.

Body proportions are usually cited as being "hyperarctic" as adaptations to the cold, because they are similar to those of human populations which developed in cold climates—the Neanderthal build is most similar to that of Inuit and Siberian Yupiks among modern humans—and shorter limbs result in higher retention of body heat. Nonetheless, Neanderthals from more temperate climates—such as Iberia—still retain the "hyperarctic" physique. In 2019, English anthropologist John Stewart and colleagues suggested Neanderthals instead were adapted for sprinting, because of evidence of Neanderthals preferring warmer wooded areas over the colder mammoth steppe, and DNA analysis indicating a higher proportion of fast-twitch muscle fibres in Neanderthals than in modern humans. He explained their body proportions and greater muscle mass as adaptations to sprinting as opposed to the endurance-oriented modern human physique, as persistence hunting may only be effective in hot climates where the hunter can run prey to the point of heat exhaustion (hyperthermia). They had longer heel bones, reducing their ability for endurance running, and their shorter limbs would have reduced moment arm at the limbs, allowing for greater net rotational force at the wrists and ankles, causing faster acceleration. In 1981, American palaeoanthropologist Erik Trinkaus made note of this alternate explanation, but considered it less likely.

Face

Neanderthal man reconstruction, Natural History Museum, London.

Neanderthals had less developed chins, sloping foreheads, and longer, broader, more projecting noses. The Neanderthal skull is typically more elongated, but also wider, and less globular than that of most modern humans, and features much more of an occipital bun, or "chignon", a protrusion on the back of the skull, although it is within the range of variation for modern humans who have it. It is caused by the cranial base and temporal bones being placed higher and more towards the front of the skull, and a flatter skullcap.

The Neanderthal face is characterised by subnasal as well as mid-facial prognathism, where the zygomatic arches are positioned in a rearward location relative to modern humans, while their maxillary bones and nasal bones are positioned in a more forward direction, by comparison. Neanderthal eyeballs are larger than those of modern humans. One study proposed that this was due to Neanderthals having enhanced visual abilities, at the expense of neocortical and social development. However, this study was rejected by other researchers who concluded that eyeball size does not offer any evidence for the cognitive abilities of Neanderthal or modern humans.

The projected Neanderthal nose and paranasal sinuses have generally been explained as having warmed air as it entered the lungs and retained moisture ("nasal radiator" hypothesis); if their noses were wider, it would differ to the generally narrowed shape in cold-adapted creatures, and that it would have been caused instead by genetic drift. Also, the sinuses reconstructed wide are not grossly large, being comparable in size to those of modern humans. However, if sinus size is not an important factor for breathing cold air, then the actual function would be unclear, so they may not be a good indicator of evolutionary pressures to evolve such a nose. Further, a computer reconstruction of the Neanderthal nose and predicted soft tissue patterns shows some similarities to those of modern Arctic peoples, potentially meaning the noses of both populations convergently evolved for breathing cold, dry air.

Neanderthals featured a rather large jaw which was once cited as a response to a large bite force evidenced by heavy wearing of Neanderthal front teeth (the "anterior dental loading" hypothesis), but similar wearing trends are seen in contemporary humans. It could also have evolved to fit larger teeth in the jaw, which would better resist wear and abrasion, and the increased wear on the front teeth compared to the back teeth probably stems from repetitive use. Neanderthal dental wear patterns are most similar to those of modern Inuit. The incisors are large and shovel-shaped, and, compared to modern humans, there was an unusually high frequency of taurodontism, a condition where the molars are bulkier due to an enlarged pulp (tooth core). Taurodontism was once thought to have been a distinguishing characteristic of Neanderthals which lent some mechanical advantage or stemmed from repetitive use, but was more likely simply a product of genetic drift. The bite force of Neanderthals and modern humans is now thought to be about the same, about 285 N (64 lbf) and 255 N (57 lbf) in modern human males and females, respectively.

Reconstruction of an elderly Neanderthal man

Brain

The Neanderthal braincase averages 1,640 cm³ (100 cu in) for males and 1,460 cm³ (89 cu in) for females, which is significantly larger than the averages for all groups of extant humans; for example, modern European males average 1,362 cm³ (83.1 cu in) and females 1,201 cm³ (73.3 cu in). For 28 modern human specimens from 190,000 to 25,000 years ago, the average was about 1,478 cm³ (90.2 cu in) disregarding sex, and modern human brain size is suggested to have decreased since the Upper Palaeolithic. The largest Neanderthal brain, Amud 1, was calculated to be 1,736 cm³ (105.9 cu in), one of the largest ever recorded in hominids. Both Neanderthal and human infants measure about 400 cm³ (24 cu in).

When viewed from the rear, the Neanderthal braincase has lower, wider, rounder appearance than in anatomically modern humans. This characteristic shape is referred to as "en bombe" (bomb-like), and is unique to Neanderthals, with all other hominid species (including most modern humans) generally having narrow and relatively upright cranial vaults, when viewed from behind. The Neanderthal brain would have been characterised by relatively smaller parietal lobes and a larger cerebellum. Neanderthal brains also have larger occipital lobes (relating to the classic occurrence of an occipital bun in Neanderthal skull anatomy, as well as the greater width of their skulls), which implies internal differences in the proportionality of brain-internal regions, relative to Homo sapiens, consistent with external measurements obtained with fossil skulls. Their brains also have larger temporal lobe poles, wider orbitofrontal cortex, and larger olfactory bulbs, suggesting potential differences in language comprehension and associations with emotions (temporal functions), decision making (the orbitofrontal cortex) and sense of smell (olfactory bulbs). Their brains also show different rates of brain growth and development. Such differences, while slight, would have been visible to natural selection and may underlie and explain differences in the material record in things like social behaviours, technological innovation and artistic output.

Hair and skin colour

The lack of sunlight most likely led to the proliferation of lighter skin in Neanderthals; however, it has been recently claimed that light skin in modern Europeans was not particularly prolific until perhaps the Bronze Age. Genetically, BNC2 was present in Neanderthals, which is associated with light skin colour; however, a second variation of BNC2 was also present, which in modern populations is associated with darker skin colour in the UK Biobank. DNA analysis of three Neanderthal females from southeastern Europe indicates that they had brown eyes, dark skin colour and brown hair, with one having red hair.

In modern humans, skin and hair colour is regulated by the melanocyte-stimulating hormone—which increases the proportion of eumelanin (black pigment) to phaeomelanin (red pigment)—which is encoded by the MC1R gene. There are five known variants in modern humans of the gene which cause loss-of-function and are associated with light skin and hair colour, and another unknown variant in Neanderthals (the R307G variant) which could be associated with pale skin and red hair. The R307G variant was identified in a Neanderthal from Monti Lessini, Italy, and possibly Cueva del Sidrón, Spain. However, as in modern humans, red was probably not a very common hair colour because the variant is not present in many other sequenced Neanderthals.

Metabolism

Maximum natural lifespan and the timing of adulthood, menopause and gestation were most likely very similar to modern humans. However, it has been hypothesised, based on the growth rates of teeth and tooth enamel, that Neanderthals matured faster than modern humans, although this is not backed up by age biomarkers. The main differences in maturation are the atlas bone in the neck as well as the middle thoracic vertebrae fused about 2 years later in Neanderthals than in modern humans, but this was more likely caused by a difference in anatomy rather than growth rate.

Generally, models on Neanderthal caloric requirements report significantly higher intakes than those of modern humans because they typically assume Neanderthals had higher basal metabolic rates (BMRs) due to higher muscle mass, faster growth rate and greater body heat production against the cold; and higher daily physical activity levels (PALs) due to greater daily travelling distances while foraging. However, using a high BMR and PAL, American archaeologist Bryan Hockett estimated that a pregnant Neanderthal would have consumed 5,500 calories per day, which would have necessitated a heavy reliance on big game meat; such a diet would have caused numerous deficiencies or nutrient poisonings, so he concluded that these are poorly warranted assumptions to make.

Neanderthals may have been more active during dimmer light conditions rather than broad daylight because they lived in regions with reduced daytime hours in the winter, hunted large game (such predators typically hunt at night to enhance ambush tactics), and had large eyes and visual processing neural centres. Genetically, colour blindness (which may enhance mesopic vision) is typically correlated with northern-latitude populations, and the Neanderthals from Vindija Cave, Croatia, had some substitutions in the Opsin genes which could have influenced colour vision. However, the functional implications of these substitutions are inconclusive. Neanderthal-derived alleles near ASB1 and EXOC6 are associated with being an evening person, narcolepsy and day-time napping.

Pathology

Neanderthals suffered a high rate of traumatic injury, with an estimated 79–94% of specimens showing evidence of healed major trauma, of which 37–52% were severely injured, and 13–19% injured before reaching adulthood. One extreme example is Shanidar 1, who shows signs of an amputation of the right arm likely due to a nonunion after breaking a bone in adolescence, osteomyelitis (a bone infection) on the left clavicle, an abnormal gait, vision problems in the left eye, and possible hearing loss (perhaps swimmer's ear). In 1995, Trinkaus estimated that about 80% succumbed to their injuries and died before reaching 40, and thus theorised that Neanderthals employed a risky hunting strategy ("rodeo rider" hypothesis). However, rates of cranial trauma are not significantly different between Neanderthals and Middle Palaeolithic modern humans (although Neanderthals seem to have had a higher mortality risk), there are few specimens of both Upper Palaeolithic modern humans and Neanderthals who died after the age of 40, and there are overall similar injury patterns between them. In 2012, Trinkaus concluded that Neanderthals instead injured themselves in the same way as contemporary humans, such as by interpersonal violence. A 2016 study looking at 124 Neanderthal specimens argued that high trauma rates were instead caused by animal attacks, and found that about 36% of the sample were victims of bear attacks, 21% big cat attacks, and 17% wolf attacks (totalling 92 positive cases, 74%). There were no cases of hyena attacks, although hyenas still nonetheless probably attacked Neanderthals, at least opportunistically. Such intense predation probably stemmed from common confrontations due to competition over food and cave space, and from Neanderthals hunting these carnivores.

La Ferrassie 1 at the Musée de l'Homme, Paris

Low population caused a low genetic diversity and probably inbreeding, which reduced the population's ability to filter out harmful mutations (inbreeding depression). However, it is unknown how this affected a single Neanderthal's genetic burden and, thus, if this caused a higher rate of birth defects than in modern humans. It is known, however, that the 13 inhabitants of Sidrón Cave collectively exhibited 17 different birth defects likely due to inbreeding or recessive disorders. Likely due to advanced age (60s or 70s), La Chapelle-aux-Saints 1 had signs of Baastrup's disease, affecting the spine, and osteoarthritis. Shanidar 1, who likely died at about 30 or 40, was diagnosed with the most ancient case of diffuse idiopathic skeletal hyperostosis (DISH), a degenerative disease which can restrict movement, which, if correct, would indicate a moderately high incident rate for older Neanderthals.

Neanderthals were subject to several infectious diseases and parasites. Modern humans likely transmitted diseases to them; one possible candidate is the stomach bacteria Helicobacter pylori. The modern human papillomavirus variant 16A may descend from Neanderthal introgression. A Neanderthal at Cueva del Sidrón, Spain, shows evidence of a gastrointestinal Enterocytozoon bieneusi infection. The leg bones of the French La Ferrassie 1 feature lesions that are consistent with periostitis—inflammation of the tissue enveloping the bone—likely a result of hypertrophic osteoarthropathy, which is primarily caused by a chest infection or lung cancer. Neanderthals had a lower cavity rate than modern humans, despite some populations consuming typically cavity-causing foods in great quantity, which could indicate a lack of cavity-causing oral bacteria, namely Streptococcus mutans.

Two 250,000-year-old Neanderthaloid children from Payré, France, present the earliest known cases of lead exposure of any hominin. They were exposed on two distinct occasions either by eating or drinking contaminated food or water, or inhaling lead-laced smoke from a fire. There are two lead mines within 25 km (16 mi) of the site.

Culture

Main article: Neanderthal behavior

Social structure

Genetically, Neanderthals can be grouped into three distinct regions (above). Dots indicate sampled specimens.

It is difficult to infer Neanderthal group size, but indirect data generally suggests small bands of 10 to 30 individuals. Bands likely moved between certain caves depending on the season, indicated by remains of seasonal materials, such as certain foods. They returned to the same locations generation after generation, and some sites may have been used for over 100 years. Intergroup movement may have been predominantly female-driven, with at least some groups practicing patrilocal residency (the woman moves out of her group to live with her mate).

Neanderthals maintained a low population across their range, which may have hindered their ability to maintain long-distance trade routes and avoid inbreeding. They may have regularly interacted with closely neighbouring communities within a region, but not as often beyond. Genetic analysis indicates there were at least three distinct geographical groups: Western Europe, the Mediterranean coast, and east of the Caucasus, with some migration among these regions.

Food

See also: Pleistocene human diet

Reconstruction of a Neanderthal man butchering a goat at the Neanderthal Museum

Neanderthals were once thought of as scavengers, but are now considered to have been apex predators. They appear to have eaten predominantly what was abundant within their immediate surroundings. Steppe-dwelling communities (generally outside of the Mediterranean) subsisted almost entirely on meat from large game; forest-dwelling communities also consumed large game but additionally a wide array of plants and smaller animals; and waterside communities gathered aquatic resources. Cro-Magnons, in contrast, seem to have used more complex food extraction strategies and generally had a more diverse diet. Neanderthals also consumed a variety of plants and mushrooms across their range. They possibly employed a wide range of cooking techniques, such as roasting, smoking, and curing.

Neanderthals competed with several large carnivores, but also seem to have hunted them down, namely cave lions, wolves, and cave bears. Neanderthals and other predators may have sometimes avoided competition by pursuing different prey, namely with cave hyenas and wolves (niche differentiation). Neanderthals, nonetheless, were frequently victims of animal attacks.

There are multiple instances of Neanderthals practicing cannibalism, but it may have only been done in times of extreme food shortages, as in some cases in recorded human history.

The arts

See also: Prehistoric art

Speculative reconstruction of white-tailed eagle talon jewellery from Krapina, Croatia (arrows indicate cut marks)

Neanderthals collected non-functional, uniquely-shaped objects, namely shells, fossils, and gems. It is unclear if these objects were simply picked up for their aesthetic qualities, or if some symbolic significance was applied to them. Some shells may have been painted. Gibraltarian palaeoanthropologists Clive and Geraldine Finlayson suggested that Neanderthals used various bird parts as artistic media, especially black feathers. There are several instances of nondescript engravings and scratches on flints, bones, pebbles, and stone slabs.

Neanderthals used ochre, a clay earth pigment. While modern humans have used this for decorative or symbolic colouration, it has also been used as medicine, hide tanning agent, food preservative, and insect repellent.

The 43,000-year-old Divje Babe flute (a cave bear femur) from Slovenia has been attributed by some researchers to Neanderthals, though its status as a Palaeolithic flute is heavily disputed. Many researchers consider it to be most likely the product of a carnivorous animal chewing the bone.

Technology

Mousterian point

Neanderthals manufactured Middle Palaeolithic stone tools, and are associated with the Mousterian industry, specifically the Levallois technique. After developing this technology from the Acheulean industry, there is a 150,000 year stagnation in Neanderthal stone tool innovation. Stalled technological growth may have followed from their low population, impeding complex ideas from being spread across their range or passed down generationally. The roughly 40,000 year old Châtelperronian industry contentiously represents a culture of Neanderthals borrowing (or by process of acculturation) tool-making techniques from immigrating modern humans. Neanderthals normally collected raw materials from a nearby source, no more than 5 km (3.1 mi). Some communities were also making tools from shells and bone. They may have hafted tips onto spears using birch bark tar.

Many Neanderthal sites have evidence of fire, some for extended periods of time, though it is unclear whether they were capable of starting fire or simply scavenged from naturally occurring wildfires. They may have been using fire for cooking, keeping warm, and deterring predators. They were also capable of zoning areas for specific activities, such as for knapping, butchering, hearths, and wood storage.

As opposed to the bone sewing-needles and stitching awls found in Cro-Magnon sites, the only known Neanderthal tools that could have been used to fashion clothes are hide scrapers. These could have been used to make items similar to blankets or ponchos. There is no direct evidence that Neanderthals could produce fitted clothes.

Neanderthals appear to have lived lives of frequent traumatic injury and recovery, indicating the setting of splints and dressing of major wounds. By and large, they appear to have avoided severe infections, indicating long-term treatment. The quality of medical care may have ensured their survival as a species for so long. Their knowledge of medicinal plants was comparable to that of Cro-Magnons.

Stone tools on various Greek islands could indicate early seafaring through the Mediterranean, employing simple reed boats for one-day crossings, but the evidence for such a big claim is limited.

Language

See also: Origin of language and Origin of speech

It is unclear if Neanderthals had the capacity for complex language, but some researchers have argued that Neanderthals required complex communications to discuss locations, hunting and gathering, and tool-making techniques in order to survive in their harsh environment. In experiments with modern humans, the Levallois technique can be taught with purely observational learning without spoken instruction.

Anatomically, the Neanderthal hyoid bone (which supports the tongue) is almost identical to that in modern humans, but this does not provide insight of the entire vocal tract. Neanderthals had the FOXP2 gene, which is associated with speech and language development, but not the modern human variant.

Burials and religion

See also: Paleolithic religion and History of religion

Engraved flint from a Neanderthal grave at Kiik-Koba, Crimea

Neanderthals, probably uncommonly, buried their dead. This may explain the abundance of fossil remains. The behaviour is not indicative of a religious belief of life after death because it could also have had non-symbolic motivations. The dead were buried in simple, shallow graves and pits, but special care seems to have been given to child graves. The graves of children and infants, especially, are associated with grave goods such as artefacts and bones. Some sites with multiple well-preserved Neanderthal skeletons may represent cemeteries.

One grave in Shanidar Cave, Iraq, was associated with the pollen of several flowers that may have been in bloom at the time of deposition—yarrow, centaury, ragwort, grape hyacinth, joint pine and hollyhock. The medicinal properties of the plants led American archaeologist Ralph Solecki to claim that the man buried was some leader, healer, or shaman, and that "The association of flowers with Neanderthals adds a whole new dimension to our knowledge of his humanness, indicating that he had 'soul' ". It is also possible the pollen was deposited by a small rodent after the man's death.

Neanderthals were once thought to have ritually killed and ate cave bears or other Neanderthals, but the evidence is circumstantial. The Finlayson's speculate that Neanderthals viewed the golden eagle as a symbol of power.

Interbreeding

Main article: Interbreeding between archaic and modern humans

Interbreeding with modern humans

Further information: Neanderthal genetics

Map of western Eurasia showing areas and estimated dates of possible Neandertal–modern human hybridisation (in red) based on fossil samples from indicated sites

The first Neanderthal genome sequence was published in 2010, and strongly indicated interbreeding between Neanderthals and early modern humans. The genomes of all studied modern populations contain Neanderthal DNA. Various estimates exist for the proportion, such as 1–4% or 3.4–7.9% in modern Eurasians, or 1.8–2.4% in modern Europeans and 2.3–2.6% in modern East Asians. Pre-agricultural Europeans appear to have had similar, or slightly higher, percentages to modern East Asians, and the numbers may have decreased in the former due to dilution with a group of people which had split off before Neanderthal introgression. Typically, studies have reported finding no significant levels of Neanderthal DNA in Sub-Saharan Africans, but a 2020 study detected 0.3-0.5% in the genomes of five African sample populations, likely the result of Eurasians back-migrating and interbreeding with Africans, as well as human-to-neanderthal gene flow from dispersals of Homo sapiens preceding the larger Out-of-Africa migration, and also showed more equal Neanderthal DNA percentages for European and Asian populations. Such low percentages of Neanderthal DNA in all present day populations indicate infrequent past interbreeding, unless interbreeding was more common with a different population of modern humans which did not contribute to the present day gene pool. Of the inherited Neanderthal genome, 25% in modern Europeans and 32% in modern East Asians may be related to viral immunity. In all, approximately 20% of the Neanderthal genome appears to have survived in the modern human gene pool.

Reconstruction of the upper Palaeolithic human Oase 2 with around 7.3% Neanderthal DNA (from an ancestor 4–6 generations back)

However, due to their small population and resulting reduced effectivity of natural selection, Neanderthals accumulated several weakly harmful mutations, which were introduced to and slowly selected out of the much larger modern human population; the initial hybridised population may have experienced up to a 94% reduction in fitness compared to contemporary humans. By this measure, Neanderthals may have substantially increased in fitness. A 2017 study focusing on archaic genes in Turkey found associations with coeliac disease, malaria severity and Costello syndrome. Nonetheless, some genes may have helped modern East Asians adapt to the environment; the putatively Neanderthal Val92Met variant of the MC1R gene, which may be weakly associated with red hair and UV radiation sensitivity, is primarily found in East Asian, rather than European, individuals. Some genes related to the immune system appear to have been affected by introgression, which may have aided migration, such as OAS1, STAT2, TLR6, TLR1, TLR10, and several related to immune response. In addition, Neanderthal genes have also been implicated in the structure and function of the brain, keratin filaments, sugar metabolism, muscle contraction, body fat distribution, enamel thickness and oocyte meiosis. Nonetheless, a large portion of surviving introgression appears to be non-coding ("junk") DNA with few biological functions.

There is considerably less Neanderthal ancestry on the X-chromosome as compared to the autosomal chromosomes. This has led to suggestions that admixture with modern humans was sex biased, and primarily the result of mating between modern human females and Neanderthal males. Other authors have suggested that this may be due to negative selection against Neanderthal alleles, however these two proposals are not mutually exclusive. A 2023 study confirmed that the low level of Neanderthal ancestry on the X-chromosomes is best explained by sex bias in the admixture events, and these authors also found evidence for negative selection on archaic genes.

Neanderthal mtDNA (which is passed on from mother to child) is absent in modern humans. This is evidence that interbreeding occurred mainly between Neanderthal males and modern human females. According to Svante Pääbo, it is not clear that modern humans were socially dominant over Neanderthals, which may explain why the interbreeding occurred primarily between Neanderthal males and modern human females. Furthermore, even if Neanderthal women and modern human males did interbreed, Neanderthal mtDNA lineages may have gone extinct if women who carried them only gave birth to sons.

The lack of Neanderthal-derived Y-chromosomes in modern humans (which is passed on from father to son), has also inspired the suggestions that the hybrids that contributed ancestry to modern populations were predominantly females, or that the Neanderthal Y-chromosome was not compatible with H. sapiens and became extinct.

According to linkage disequilibrium mapping, the last Neanderthal gene flow into the modern human genome occurred 86–37,000 years ago, but most likely 65–47,000 years ago. It is thought that Neanderthal genes which contributed to the present day human genome stemmed from interbreeding in the Near East rather than the entirety of Europe. However, interbreeding still occurred without contributing to the modern genome. The approximately 40,000-year-old modern human Oase 2 was found, in 2015, to have had 6–9% (point estimate 7.3%) Neanderthal DNA, indicating a Neanderthal ancestor up to four to six generations earlier, but this hybrid population does not appear to have made a substantial contribution to the genomes of later Europeans. In 2016, the DNA of Neanderthals from Denisova Cave revealed evidence of interbreeding 100,000 years ago, and interbreeding with an earlier dispersal of H. sapiens may have occurred as early as 120,000 years ago in places such as the Levant. The earliest H. sapiens remains outside of Africa occur at Misliya Cave 194–177,000 years ago, and Skhul and Qafzeh 120–90,000 years ago. The Qafzeh humans lived at approximately the same time as the Neanderthals from the nearby Tabun Cave. The Neanderthals of the German Hohlenstein-Stadel have deeply divergent mtDNA compared to more recent Neanderthals, possibly due to introgression of human mtDNA between 316,000 and 219,000 years ago, or simply because they were genetically isolated. Whatever the case, these first interbreeding events have not left any trace in modern human genomes.

Genetic evidence suggests that following their split from Denisovans, Neanderthals experienced gene flow (around 3% of their genome) from the lineage leading to modern humans prior to the expansion of modern humans outside of Africa during the Last Glacial Period, with this interbreeding suggested to have taken place around 200–300,000 years ago.

Detractors of the interbreeding model argue that the genetic similarity is only a remnant of a common ancestor instead of interbreeding, although this is unlikely as it fails to explain why sub-Saharan Africans do not have Neanderthal DNA.

Interbreeding with Denisovans

Chris Stringer's Homo family tree. The horizontal axis represents geographic location, and the vertical time in millions of years ago.

Although nDNA confirms that Neanderthals and Denisovans are more closely related to each other than they are to modern humans, Neanderthals and modern humans share a more recent maternally-transmitted mtDNA common ancestor, possibly due to interbreeding between Denisovans and some unknown human species. The 400,000-year-old Neanderthal-like humans from Sima de los Huesos in northern Spain, looking at mtDNA, are more closely related to Denisovans than Neanderthals. Several Neanderthal-like fossils in Eurasia from a similar time period are often grouped into H. heidelbergensis, of which some may be relict populations of earlier humans, which could have interbred with Denisovans. This is also used to explain an approximately 124,000-year-old German Neanderthal specimen with mtDNA that diverged from other Neanderthals (except for Sima de los Huesos) about 270,000 years ago, while its genomic DNA indicated divergence less than 150,000 years ago.

Sequencing of the genome of a Denisovan from Denisova Cave has shown that 17% of its genome derives from Neanderthals. This Neanderthal DNA more closely resembled that of a 120,000-year-old Neanderthal bone from the same cave than that of Neanderthals from Vindija Cave, Croatia, or Mezmaiskaya Cave in the Caucasus, suggesting that interbreeding was local.

For the 90,000-year-old Denisova 11, it was found that her father was a Denisovan related to more recent inhabitants of the region, and her mother a Neanderthal related to more recent European Neanderthals at Vindija Cave, Croatia. Given how few Denisovan bones are known, the discovery of a first-generation hybrid indicates interbreeding was very common between these species, and Neanderthal migration across Eurasia likely occurred sometime after 120,000 years ago.

Extinction

Main article: Neanderthal extinction

Transition

Map emphasising the Ebro River in northern Spain

The extinction of Neanderthals was part of the broader Late Pleistocene megafaunal extinction event. Whatever the cause of their extinction, Neanderthals were replaced by modern humans, indicated by near full replacement of Middle Palaeolithic Mousterian stone technology with modern human Upper Palaeolithic Aurignacian stone technology across Europe (the Middle-to-Upper Palaeolithic Transition) from 41,000 to 39,000 years ago. By between 44,200 and 40,600 BP, Neanderthals vanished from northwestern Europe. However, it is postulated that Iberian Neanderthals persisted until about 35,000 years ago, as indicated by the date range of transitional lithic assemblages—Châtelperronian, Uluzzian, Protoaurignacian and Early Aurignacian. The latter two are attributed to modern humans, but the former two have unconfirmed authorship, potentially products of Neanderthal/modern human cohabitation and cultural transmission. Further, the appearance of the Aurignacian south of the Ebro River has been dated to roughly 37,500 years ago, which has prompted the "Ebro Frontier" hypothesis which states that the river presented a geographic barrier preventing modern human immigration, and thus prolonging Neanderthal persistence. However, the dating of the Iberian Transition is debated, with a contested timing of 43,000–40,800 years ago at Cueva Bajondillo, Spain. The Châtelperronian appears in northeastern Iberia about 42,500–41,600 years ago.

Some Neanderthals in Gibraltar were dated to much later than this—such as Zafarraya (30,000 years ago) and Gorham's Cave (28,000 years ago)—which may be inaccurate as they were based on ambiguous artefacts instead of direct dating. A claim of Neanderthals surviving in a polar refuge in the Ural Mountains is loosely supported by Mousterian stone tools dating to 34,000 years ago from the northern Siberian Byzovaya site at a time when modern humans may not yet have colonised the northern reaches of Europe; however, modern human remains are known from the nearby Mamontovaya Kurya site dating to 40,000 years ago. Indirect dating of Neanderthals remains from Mezmaiskaya Cave reported a date of about 30,000 years ago, but direct dating instead yielded 39,700 ±1,100 years ago, more in line with trends exhibited in the rest of Europe.

Bohunician scrapers in the Moravian Museum, Czech Republic

The earliest indication of Upper Palaeolithic modern human immigration into Europe is a series of modern human teeth with Neronian industry stone tools found at Mandrin Cave, Malataverne in France, dated in 2022 to between 56,800 and 51,700 years ago. The earliest bones in Europe date to roughly 45–43,000 years ago in Bulgaria, Italy, and Britain. This wave of modern humans replaced Neanderthals. However, Neanderthals and H. sapiens have a much longer contact history. DNA evidence indicates H. sapiens contact with Neanderthals and admixture as early as 120–100,000 years ago. A 2019 reanalysis of 210,000-year-old skull fragments from the Greek Apidima Cave assumed to have belonged to a Neanderthal concluded that they belonged to a modern human, and a Neanderthal skull dating to 170,000 years ago from the cave indicates H. sapiens were replaced by Neanderthals until returning about 40,000 years ago. This identification was refuted by a 2020 study. Archaeological evidence suggests that Neanderthals displaced modern humans in the Near East around 100,000 years ago until about 60–50,000 years ago.

Cause

Modern humans

Successive dispersals of Homo erectus (yellow), Neanderthals (ochre) and modern humans (red).

Historically, modern human technology was viewed as vastly superior to that of Neanderthals, with more efficient weaponry and subsistence strategies, and Neanderthals simply went extinct because they could not compete.

The discovery of Neanderthal/modern human introgression has caused the resurgence of the multiregional hypothesis, wherein the present day genetic makeup of all humans is the result of complex genetic contact among several different populations of humans dispersed across the world. By this model, Neanderthals and other recent archaic humans were simply assimilated into the modern human genome – that is, they were effectively bred out into extinction. Modern humans coexisted with Neanderthals in Europe for around 3,000 to 5,000 years.

Climate change

Their ultimate extinction coincides with Heinrich event 4, a period of intense seasonality; later Heinrich events are also associated with massive cultural turnovers when European human populations collapsed. This climate change may have depopulated several regions of Neanderthals, like previous cold spikes, but these areas were instead repopulated by immigrating humans, leading to Neanderthal extinction. In southern Iberia, there is evidence that Neanderthal populations declined during H4 and the associated proliferation of Artemisia-dominated desert-steppes.

Dispersal of deposits during the Campanian Ignimbrite Eruption around 40,000 years ago.

It has also been proposed that climate change was the primary driver, as their low population left them vulnerable to any environmental change, with even a small drop in survival or fertility rates possibly quickly leading to their extinction. However, Neanderthals and their ancestors had survived through several glacial periods over their hundreds of thousands of years of European habitation. It is also proposed that around 40,000 years ago, when Neanderthal populations may have already been dwindling from other factors, the Campanian Ignimbrite Eruption in Italy could have led to their final demise, as it produced 2–4 °C (3.6–7.2 °F) cooling for a year and acid rain for several more years.

Disease

Modern humans may have introduced African diseases to Neanderthals, contributing to their extinction. A lack of immunity, compounded by an already low population, was potentially devastating to the Neanderthal population, and low genetic diversity could have also rendered fewer Neanderthals naturally immune to these new diseases ("differential pathogen resistance" hypothesis). However, compared to modern humans, Neanderthals had a similar or higher genetic diversity for 12 major histocompatibility complex (MHC) genes associated with the adaptive immune system, casting doubt on this model.

Low population and inbreeding depression may have caused maladaptive birth defects, which could have contributed to their decline (mutational meltdown).

In late-20th-century New Guinea, due to cannibalistic funerary practices, the Fore people were decimated by transmissible spongiform encephalopathies, specifically kuru, a highly virulent disease spread by ingestion of prions found in brain tissue. However, individuals with the 129 variant of the PRNP gene were naturally immune to the prions. Studying this gene led to the discovery that the 129 variant was widespread among all modern humans, which could indicate widespread cannibalism at some point in human prehistory. Because Neanderthals are known to have practised cannibalism to an extent and to have co-existed with modern humans, British palaeoanthropologist Simon Underdown speculated that modern humans transmitted a kuru-like spongiform disease to Neanderthals, and, because the 129 variant appears to have been absent in Neanderthals, it quickly killed them off.

In popular culture

Main article: Neanderthals in popular culture

Cavemen in The Black Terror #16 (1946)

Neanderthals have been portrayed in popular culture including appearances in literature, visual media and comedy. The "caveman" archetype often mocks Neanderthals and depicts them as primitive, hunchbacked, knuckle-dragging, club-wielding, grunting, nonsocial characters driven solely by animal instinct. "Neanderthal" can also be used as an insult.

In literature, they are sometimes depicted as brutish or monstrous, such as in H. G. Wells' The Grisly Folk and Elizabeth Marshall Thomas' The Animal Wife, but sometimes with a civilised but unfamiliar culture, as in William Golding's The Inheritors, Björn Kurtén's Dance of the Tiger, and Jean M. Auel's Clan of the Cave Bear and her Earth's Children series.

See also

• Denisovan – Asian archaic human
• Early human migrations
• Cro-Magnon – Earliest anatomically modern humans in Europe
• Homo floresiensis – Extinct small human species found in Flores
• Homo luzonensis – Archaic human from Luzon, Philippines
• Homo naledi – South African archaic human species
• Timeline of human evolution

Sources

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• Romagnoli, Francesca; Rivals, Florent; Benazzi, Stefano (2022). Updating Neanderthals: Understanding Behavioural Complexity in the Late Middle Palaeolithic. Academic Press. ISBN 978-0-12-821429-9.
• Finlayson, C. (2019). The smart Neanderthal: bird catching, cave art, and the cognitive revolution. Oxford University Press. ISBN 978-0-19-251812-5.
• French, Jennifer (2021). Palaeolithic Europe: A Demographic and Social Prehistory. Cambridge, UK: Cambridge University Press. ISBN 978-1-108-49206-5.
• Papagianni, D.; Morse, M. A. (2013). "Still with us?". Neanderthals rediscovered: how modern science is rewriting their story. Thames and Hudson. ISBN 978-0-500-77311-6.
• Pettitt, Paul; White, Mark (2012). The British Palaeolithic: hominin societies at the edge of the Pleistocene world. London: Routledge. ISBN 978-0415674546.
• Reich, D. (2018). "Encounters with Neanderthals". Who we are and how we got here: ancient DNA and the new science of the human past. Oxford University Press. ISBN 978-0-19-882125-0.
• Shipman, P. (2015). "How humans and their dogs drove Neanderthals to extinction". The invaders: how humans and their dogs drove Neanderthals to extinction. Harvard University Press. doi:10.2307/j.ctvjf9zbs. ISBN 978-0-674-42538-5. JSTOR j.ctvjf9zbs.
• Stringer, C.; Gamble, C. (1993). In search of the Neanderthals. Thames and Hudson. ISBN 978-0-500-05070-5.
• Sykes, Rebecca Wragg (2020). Kindred: Neanderthal Life, Love, Death and Art. London, UK: Bloomsbury Sigma. ISBN 978-1-4729-3749-0.
• Tattersall, I. (2015). "Neanderthals, DNA, and creativity". The strange case of the Rickety Cossack: and other cautionary tales from human evolution. St. Martin's Publishing Group. ISBN 978-1-4668-7943-0.

Further reading

• Hunt, Chris; et al. (August 28, 2023). "Shanidar et ses fleurs? Reflections on the palynology of the Neanderthal 'Flower Burial' hypothesis". Journal of Archaeological Science. 159: 105822. Bibcode:2023JArSc.159j5822H. doi:10.1016/j.jas.2023.105822. S2CID 261325698.

External links

• Proof that Neanderthals ate crabs is another 'nail in the coffin' for primitive cave dweller stereotypes - Phys.org February 7, 2023
• "Homo neanderthalensis". The Smithsonian Institution. February 14, 2010.
• Human Timeline (Interactive) – Smithsonian, National Museum of Natural History (August 2016).
• "Neanderthal DNA". International Society of Genetic Genealogy. Archived from the original on June 17, 2006.: Includes Neanderthal mtDNA sequences
• GenBank records for H. s. neanderthalensis maintained by the National Center for Biotechnology Information (NCBI)
• Alex, Bridget (February 21, 2024). "What's Behind the Evolution of Neanderthal Portraits". SAPIENS.