Neanderthals

Neanderthal Temporal range: Middle to LatePleistocene 0.6–0.03 Ma PreЄ Є O S D C P T J K Pg N ↓
Neanderthal skull, La Chapelle-aux-Saints
Mounted Neanderthal skeleton, American Museum of Natural History
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Primates
Family:	Hominidae
Genus:	Homo
Species:	H. neanderthalensis
Binomial name
Homo neanderthalensis King, 1864
Range of Homo neanderthalensis. Eastern and northern ranges may extend to include Okladnikov in Altai and Mamotnaia in Ural
Synonyms
Palaeoanthropus neanderthalensis[citation needed] H. s. neanderthalensis

Neanderthals were members of a now-extinct species, or species sub-group,^[1] closely related to modern humans that is known fromPleistocene specimens found in Europe and parts of western and central Asia. Like modern humans they are classified as part of thegenus Homo. The term "Neanderthal", a shortening of "Neanderthal man", is sometimes spelled Neandertal, the modern spelling of the location in Germany where the species was first discovered.

Neanderthals are classified alternatively as a subspecies of Homo sapiens (Homo sapiens neanderthalensis) or as a separate humanspecies (Homo neanderthalensis).^[2] Genetic evidence suggests they are closer to non-African than African anatomically modern humans, which is probably due to interbreeding between Neanderthals and the ancestors of the Eurasians. This is thought to have occurred between 80,000 and 50,000 years ago, shortly after (or perhaps before) the proto-Eurasians emigrated from Africa, and while they were still one population. It resulted in 1–4% of the genome of people from Eurasia having been contributed by Neanderthals.^[3][4][5]

The first proto-Neanderthal traits appeared in Europe as early as 600,000–350,000 years ago.^[6] Proto-Neanderthal traits are occasionally grouped with another phenetic 'species', Homo heidelbergensis, or a migrant form, Homo rhodesiensis.

The youngest Neanderthal finds include Hyena Den (UK), considered older than 30,000 years ago, while the Vindija (Croatia) Neanderthals have been re-dated to between 33,000 and 32,000 years ago. No definite specimens younger than 30,000 years ago have been found; however, evidence of fire by Neanderthals at Gibraltar indicate they may have survived there until 24,000 years ago. Cro-Magnon or early modern human skeletal remains with 'Neanderthal traits' were found in Lagar Velho (Portugal), dated to 24,500 years ago and interpreted as indications of extensively admixed populations.^[7]

Several cultural assemblages have been linked to the Neanderthals in Europe. The earliest, the Mousterian stone tool culture, dates to about 300,000 years ago.^[8] Late Mousterian artifacts were found in Gorham's Cave on the remote south-facing coast of Gibraltar.^[9][10]Other tool cultures associated with Neanderthal include Châtelperronian, Aurignacian, and Gravettian. These latter tool assemblages appear to have developed gradually within the populations, rather than being introduced by new population groups arriving in the region.^[11]

Neanderthal cranial capacity is thought to have been as large as that of modern humans, perhaps larger, indicating their brain size may have been comparable, or larger, as well. In 2008, a group of scientists created a study using three-dimensional computer-assisted reconstructions of Neanderthal infants based on fossils found in Russia and Syria. The study showed Neanderthal and modern human brains were the same size at birth, but by adulthood, the Neandertal brain was larger than the modern human brain.^[12] They were much stronger than modern humans, having particularly strong arms and hands.^[13] Males stood 164–168 cm (65–66 in) and females about 152–156 cm (60–61 in) tall.^[14]

Extinction hypotheses

Main article: Neanderthal extinction hypotheses

The Neanderthals disappear from the fossil record after about 25,000 years ago. The last traces of Mousterian culture (without human specimens) have been found in Gorham's Caveon the remote south-facing coast of Gibraltar, dated 30,000 to 24,500 years ago. Possible scenarios are:

1. Neanderthals were a separate species from modern humans, and became extinct (due to climate change or interaction with humans) and were replaced by modern humans moving into their habitat beginning around 80,000 years ago.^[70] Competition with humans probably contributed to Neanderthal extinction.^[71] [72] Jared Diamond has suggested a scenario of violent conflict and displacement.^[73]
2. Neanderthals were a contemporary subspecies that bred with modern humans and disappeared through absorption (interbreeding theory).
3. A Campanian ignimbrite volcanic super-eruption around 40,000 years ago, followed by a second one a few thousand years later, has been hypothesised as having contributed to the demise of the Neanderthal, based on evidence from Mezmaiskaya cave in the Caucasus Mountains of southern Russia ^[74][75] Mitochondrial DNA (mtDNA) analysis of a specimen from Mezmaiskaya Cave is radiocarbon dated to be about 29,000 years BP and therefore from one of the latest living Neanderthal individuals. The sequence shows 3.48% divergence from the Feldhofer Neanderthal4. Phylogenetic analysis places the two Neanderthals from the Caucasus and western Germany together in a clade that is distinct from modern humans, suggesting that their mtDNA types have not contributed to the modern human mtDNA pool.