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Neanderthals

The Neanderthals or Neandertals are an extinct species or subspecies of the genus Homo which is closely related to modern humans. They are known from fossils, dating back from the Pleistocene period, which have been found in Europe and parts of western and central Asia. The species gets its name from Neandertal, “Neander’s Valley”, the location in Germany where it was first uncovered.

Neanderthals are classified either as a subspecies of Homo sapiens or as a distinct species of the same genus. The first humans with proto-Neanderthal characteristics are believed to have existed in Europe as early as 600,000 to 350,000 years ago.

When the Neanderthals became extinct is uncertain. Fossils found in the Vindija Cave located in Croatia have been dated to between 33,000 and 32,000 years old, and Neanderthal artifacts from Gorham’s Cave located in Gibraltar are believed to be less than 30,000 years old, but a recent study has re-dated fossils at two Spanish sites as 45,000, 10,000 years older than what was previously thought, and might cast uncertainty on recent datings of other sites. Cro-Magnon, early-modern-human, skeletal remains displaying specific “Neanderthal traits” have been found in Lagar Velho and dated to 24,500 years old, proposing that there might have been a wide-ranging admixture of the Cro-Magnon and Neanderthal populations in that area.

Numerous cultural groups have been associated to the Neanderthals in Europe. The earliest, the Mousterian stone tool culture, dates back about 300,000 years ago. Late Mousterian artifacts were uncovered in Gorham’s Cave on the south-facing coast of Gibraltar. Other tool cultures linked with the Neanderthals include the Chatelperronian, the Aurignacian, and the Gravettian; their tool collections seem to have developed steadily within their populations, as opposed to being introduced by new population groups arriving within the region.

Neanderthal cranial capacity is though to have been as large as that of modern humans, maybe even larger, signifying that their brain size might have been at least as large as ours. In 2008, a group of scientists formed a study utilizing three-dimensional computer-assisted reconstructions of Neanderthal infants based on fossils that were found in Russia and Syria. The study suggested that Neanderthal and modern human brains were the same size at the time of birth, but by adulthood, the Neanderthal brain was larger than the modern human brain. They were much stronger than the modern humans, having especially strong hands and arms.

Genetic evidence published in the year 2010 suggests that Neanderthals contributed to the DNA of anatomically modern humans, most likely through interbreeding between 80,000 and 50,000 years ago with the population of anatomically modern humans who had recently migrated from Africa. In accordance with the study, by the time that population started scattering across Eurasia, Neanderthal genes represented as much as 1 to 4 percent of its genome. Otzi the iceman, Europe’s oldest preserved mummy, was noticed to possess an even higher percentage of Neanderthal ancestry.

The species is named after the site of its first discovery, about 7.5 miles east of Dusseldorf, Germany, in the Feldhofer Cave located in the river Dussel’s Neander valley named for Joachim Neander, a 17th century German pastor and hymnist. Neander’s own name was, in turn, a Greek translation of the German Neumann, meaning “New man”. Thal is the older spelling of Tal, the German world for valley.

Neanderthal 1 was known as the “Neanderthal skull” or “Neanderthal cranium” in anthropological literature, and the individual reconstructed on the basis of the skull was sometimes called “the Neanderthal man”. The binomial name Homo neanderthalensis – extending the name “Neanderthal Man” from the individual type specimen to the entire species – was initially suggested by the Anglo-Irish geologist William King in 1864 and this had priority over the suggestion put forward in 1866 by Ernst Haeckel, Homo stupidus. The practice of referring to “the Neanderthals” and “a Neanderthal” surfaced in the popular literature of the 1920s.

For quite some time, scientists have argued whether Neanderthals should be classified as Homo neanderthalensis or Homo sapiens neanderthalensis, the latter putting Neanderthals as a subspecies of H. sapiens. Some morphological research supports the view that H. neanderthalensis is a separate species and not a subspecies. Others, for example University of Cambridge Professor Paul Mellars, say “no evidence has been found of cultural interaction” and evidence from mitochondrial DNA studies has been construed as evidence Neanderthals weren’t a subspecies of H. sapiens. Since species can be defined by reproductive seclusion, strong genomic evidence of interbreeding between the two races has led some scientists to lean towards classifying the Neanderthal as a subspecies of H. sapiens, but there are documented examples of fertile inter-specific hybridization and introgression, so this is final.

Comparing the DNA of Neanderthals and Homo sapiens proposes that they diverged from a common ancestor between 350,000 and 400,000 years ago. This ancestor isn’t certain, but was most likely Homo heidelbergensis. Heidelbergensis originated between 800,000 and 1,300,000 years ago, and survived until about 200,000 years ago. Its range extended over east and South Africa, Europe and west Asia. Between 350,000 and 400,000 years ago the African division is thought to have started evolving towards modern humans and the European division towards Neanderthals. Scientists don’t concur when Neanderthals can first be recognized in the fossil record, with dates ranging from 200,000 to 300,000 years before the present.

Neanderthal skulls were first discovered in Engis Caves in what is now Belgium by Philippe-Charles Schmerling and in Forbes’ Quarry, Gibraltar, given the name Gibraltar 1, both preceding the type specimen discovery in a limestone quarry of the Neander Valley located in Erkrath near Dusseldorf in August of 1856, three years before Charles Darwin’s “On the Origin of Species” was published.

The type specimen, named Neanderthal 1, was made up of a skull cap, two femora, three bones from the right arm, two from the left arm, part of the left ilium, pieces of a scapula, and ribs. The workers who uncovered these objects originally thought it to be the remains of a bear. They gave the material to amateur naturalist Johann Carl Fuhlrott, who turned the fossils over to anatomist Hermann Schaaffhausen. The discovery was jointly declared in the year 1857.

To date, more than 400 Neanderthal bones have been found.

Early Neanderthals lived in the Last glacial period for a length of about 100,000 years. Due to the damaging effects the glacial period had on the Neanderthal sites, not much is known about the early species. Countries where their remains are known include the majority of Europe south of the line of glaciation, roughly along the 50th parallel north, including most of Western Europe, including the south coast of Great Britain, Central Europe and the Balkans, some sites in Ukraine and in western Russia and east of Europe in Siberia to the Altai Mountains and south through the Levant to the Indus River. It’s estimated that the whole Neanderthal population across this habitat range amounted to around 70,000 at its peak.

Neanderthal fossils haven’t been found to date in Africa, but there have been finds quite close to Africa, both on Gibraltar and in the Levant. At some Levantine sites, Neanderthal remains, indeed, date from after the same sites were left by modern humans. Mammal fossils of the same time period display cold-adapted animals were present alongside these Neanderthals in this area of the Eastern Mediterranean. This implies Neanderthals were better adapted biologically to cold weather than the modern humans and, at times, displaced them in parts of the Middle East when the climate got cold enough.

H. sapiens sapiens appear to have been the only human type within the Nile River Valley during these time periods, and Neanderthals aren’t known to have ever inhabited south-west of modern Israel. When further climate change produced warmer temperatures, the Neanderthal range also fled to the north along with the cold-adapted species of mammals. It appears that these weather-provoked population shifts occurred before modern people held competitive advantages over the Neanderthal, as these shifts in range occurred well over then thousand years before modern people entirely replaced the Neanderthal, in spite of the recent evidence of some successful interbreeding.

There were separate developments in the human line, in other areas such as Southern Africa, that resembled the European and Western/Central Asian Neanderthals, but these people weren’t truly Neanderthals. For example, Rhodesian Man who existed long before any classic European Neanderthals, but had a more modern array of teeth, and debatably some H. rhodesiensis populations were on the road to modern H. sapiens sapiens. In any case, the populations in Europe and West/Central Asia experienced more and more “Neanderthalization” as time went by. There is some debate that H. rhodesiensis overall was ancestral to both modern humans and Neanderthals, and that at some point the two populations went their separate ways, but this supposes that H. rhodesiensis dates back to around 600,000 years ago.

Thus far, no personal connection has been found between these similar archaic people and the Western/Central Eurasian Neanderthals, at least during the same time as classic Eurasian Neanderthals, and H. rhodesiensis appears to have lived about 600,000 years ago, long before the time of classic Neanderthals. With that said, some researchers think that H. rhodesiensis might have lived much later than this period, depending on the technique used to date the fossils, leaving this problem open for debate. Some H. rhodesiensis traits, like the huge brow ridge, might have been triggered by convergent evolution. There is no evidence so far saying Neanderthals knew how to built boats or rafts, and the scarceness of human fossils in North Africa west of the Nile Valley should be noted.

It appears erroneous, based on present research and known fossil finds, to refer to any fossils outside of Europe or Western and Central Asia as accurate Neanderthals. They had a known range that might have extended as far east as the Altai Mountains, but not farther to the east or to the south, and evidently not into Africa. In any case, in North-East Africa the land directly south of the Neanderthal range was acquired by modern humans, Homo sapiens idaltu or Homo sapiens, since at least 160,000 years prior to the present. 160,000 year old hominid fossils at Jebel Irhoud located in Morocco were formerly thought to be Neanderthal, but it’s now evident that they are early modern humans.

The anatomy of the Neanderthal differed from modern humans in that they had a more robust physique and distinctive morphological features, particularly on the cranium, which steadily build up more derivative features, especially in specific isolated areas. Evidence insinuates that they were much stronger than the modern humans, while they were similar in height; based on 45 long bones from at most 14 males and 7 females, Neanderthal males averaged 65 to 66 inches (5 feet 4 inches to 5 feet 5 inches) and the females 60 to 61 inches (5 feet) tall. Samples of 26 specimens in the year 2010 found an average weight of 171 pounds for the males and 146 pounds for the females. A genetic study taken place in 2007 proposed some Neanderthals might have had red hair and light skin color.

Neanderthals constructed advanced tools, had a language and lived in intricate social groups. The Molodova archaeological site in eastern Ukraine indicated some Neanderthals manufactured residences utilizing animal bones. A building consisted of mammoth skull, jaws, tusks, and leg bones, and had 25 hearths inside.

While mostly carnivorous, and apex predators; new studies imply Neanderthals had cooked vegetables within their diet. In the year 2010, a U.S. researcher reported finding cooked vegetable substances in the teeth of a Neanderthal skull, disagreeing with the earlier belief that they were completely, or almost completely, carnivorous and apex predators.

Early studies focused on mitochondrial DNA (mtDNA), which, owing to precisely matrilineal inheritance and consequent vulnerability to genetic drift, is of limited worth in assessing the prospect of interbreeding of Neanderthals with Cro-Magnon people.

In 1997, geneticists had the ability to remove a short sequence of DNA from Neanderthal bones from 30,000 years ago. The removal of mtDNA from a second specimen was reported in 2000, and displayed no indication of modern human descent from Neanderthals.

In July of 2006, the Max Planck Institute for Evolutionary Anthropology and 454 Life Sciences proclaimed that they would sequence the Neanderthal genome over the next two years. This genome is expected to be about the size of the human genome, three-billion base pairs, and share the majority of its genes. It was hoped the comparison would increase the understanding of Neanderthals, in addition to the evolution of humans and human brains.

Svante Paabo has assessed more than 70 Neanderthal specimens. Opening DNA sequencing from a 38,000 year old bone fragment of a femur found at Vindija Cave, Croatia, in 1980 reveals that Neanderthals and modern humans share about 99.5 percent of their DNA. From mtDNA estimates, the two species shared a mutual ancestor about 500,000 years ago. An article, appearing in the journal Nature has calculated the species diverged about 516,000 years ago, whereas fossil records imply a time of about 400,000 years ago. A study taken place in 2007 pushes the moment of divergence back to around 800,000 years ago.

On November 16 of 2006, Lawrence Berkeley National Laboratory issued a press release stating Neanderthals and ancient humans most likely didn’t interbreed. Edward M. Rubin, director of the U. S. Department of Energy’s Lawrence Berkeley Laboratory and the Joint Genome Institute  (JGI), sequenced a fraction of genomic nuclear DNA (nDNA) from a 38,000 year old Vindia Neanderthal femur. They assessed the common ancestor to be around 353,000 years ago, and a total division of the ancestors of the species about 188,000 years ago.

Their conclusions show that the genomes of modern humans and Neanderthals are at least 99.5 percent identical, but in spite of this genetic similarity and the two species having coexisted in the same geographic area for thousands of years, Rubin and his team didn’t find any proof of any noteworthy crossbreeding between the two. Rubin quoted, “While unable to definitively conclude that interbreeding between the two species of humans did not occur, analysis of the nuclear DNA from the Neanderthal suggests the low likelihood of it having occurred at any appreciable level.”

With three billion nucleotides sequenced, examination of about one-third displayed no indication of admixture between modern humans and Neanderthals, according to Paabo. This coincided with the work of Noonan from two years prior. The variant of microcephalin common outside of Africa, which was suggested to be of Neanderthal derivation and accountable for fast brain growth in humans, wasn’t found in Neanderthals. Neither was the MAPT variant, a very old variant found mostly in Europeans.

Neanderthal fossils discovered in Vindija Cave in Croatia have been dated to between 32,000 and 33,000 years old, and what have been declared the last traces of Mousterian culture have been discovered in Gorham’s Cave on the secluded south-facing coast of Gibraltar, dated to less than 30,000 years ago. However, a recent re-investigation of Neanderthal bones from two Spanish Neanderthal sites has implied that they were around 45,000 years old, 10,000 years older than what was previously thought. Professor Clive Finlayson, who excavated Gorham’s Cave, argues that the sites which have been re-dated are highland sites which would have been formidable in the approach of an ice age. However, bone collagen decays in the warmer lowland sites where Finlayson presumes Neanderthals would have survived longer, and it has yet to be decided whether the re-dating influences other Neanderthal sites with reported recent dates.

Around 55,000 years ago, the weather started to fluctuate violently from intense cold to mild cold and back in a matter of a few decades. The bodies of Neanderthals were well suited for surviving in a cold climate – their barrel chests and sturdy limbs stored body heat more efficiently than the Cro-Magnons. However, the quick fluctuations of weather produce ecological alterations to which the Neanderthals couldn’t adapt to; familiar plants and animals would be swapped with entirely different ones within a lifetime. The Neanderthals’ ambush methods would not have succeeded as grasslands replaced the trees. A large number of Neanderthals would have died during these fluctuations, which climaxed about 30,000 years ago.

Some studies on the Neanderthals body structures have shown that they required more energy to survive than any other species of hominid. Their energy requirements were up to 100 to 350 calories more each day comparing to projected anatomically modern human males weighing around 151 pounds and females weighing around 130 pounds. When the food became inadequate, this difference might have played a significant role in the Neanderthals’ extinction.

Image Caption: Homo neanderthalensis. Skull discovered in 1908 at La Chapelle-aux-Saints (France). Credit: Luna04/Wikipedia (CC BY-SA 3.0)

Neanderthals


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