Neanderthal

Neanderthals (/niˈændərˌtɑːl, neɪ-, -ˌθɑːl/ nee-AN-də(r)-TAHL, nay-, -⁠THAHL; Homo neanderthalensis or H. sapiens neanderthalensis), are an extinct species or subspecies of archaic humans 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. Theories for their extinction include demographic factors such as small population size and inbreeding, competitive replacement, interbreeding and assimilation with modern humans, change of climate, disease, or a combination of these factors.

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. In truth, Neanderthal technology was quite sophisticated. It includes the Mousterian stone-tool industry as well as the abilities to create fire, build cave hearths (to cook food, keep warm, defend themselves from animals, placing it at the centre of their homes), make adhesive birch bark tar, craft at least simple clothes similar to blankets and ponchos, weave, go seafaring through the Mediterranean, make use of medicinal plants, treat severe injuries, store food, and use various cooking techniques such as roasting, boiling, and smoking. Neanderthals consumed a wide array of food, mainly hoofed mammals, but also megafauna, plants, small mammals, birds, and aquatic and marine resources. 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, namely possible ornaments made from bird claws and feathers, shells, collections of unusual objects including crystals and fossils, engravings, music production (possibly indicated by the Divje Babe flute), and Spanish cave paintings contentiously dated to before 65,000 years ago. 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.

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, but 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 and an enlarged nose to warm air (although the nose could have been caused by genetic drift). 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 (1,260 cm³ (77 cu in) and 1,130 cm³ (69 cu in), respectively). The Neanderthal skull was more elongated and the brain had smaller parietal lobes and cerebellum, but larger temporal, occipital and orbitofrontal regions.

The total population of Neanderthals remained low, proliferating weakly harmful gene variants and precluding effective long-distance networks. Despite this, there is evidence of regional cultures and regular communication between communities. They may have frequented caves and moved between them seasonally. Neanderthals lived in a high-stress environment with high trauma rates, and about 80% died before the age of 40.

The 2010 Neanderthal genome project's draft report presented evidence for interbreeding between Neanderthals and modern humans. It possibly occurred 316,000 to 219,000 years ago, but more likely 100,000 years ago and again 65,000 years ago. 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. Although many of the gene variants inherited from Neanderthals may have been detrimental and selected out, Neanderthal introgression appears to have affected the modern human immune system, and is also implicated in several other biological functions and structures, but a large portion appears to be non-coding DNA.