Neanderthals (pronounced nee-AN-dər-TAHHL or nay-THAHL) were an extinct group of early humans who lived in Europe and parts of Asia during the Middle and Late Pleistocene periods. They became extinct around 40,000 years ago when modern humans (called Cro-Magnons) arrived in their regions. However, some Neanderthals in Gibraltar may have survived for thousands of years longer.

The first Neanderthal fossil, known as Neanderthal 1, was found in 1856 in a valley in Germany. At first, scientists thought Neanderthals were part of a lower race group based on outdated ideas about human races. As more fossils were discovered in the early 20th century, scientists, including Marcellin Boule, began to see Neanderthals as a distinct species of early humans. By the mid-20th century, it was believed that humans evolved from ape-like ancestors through a "Neanderthal phase" before becoming modern humans. This idea helped form the "Out of Africa" theory in the 1970s. Later, in 2010, scientists studied the Neanderthal genome and found that Neanderthals interbred with modern humans.

Neanderthals had a long, low skull, thick brow ridges, a bony bump at the back of the skull, strong teeth and jaws, a wide chest, and short limbs. These traits became more common in Europe during the Middle Pleistocene, possibly because of cold climates and genetic changes when populations decreased during ice ages. Neanderthals ranged in height from about 147.5 to 177 cm (4 ft 10 in to 5 ft 10 in), with average males measuring about 165 cm (5 ft 5 in) and weighing around 75 kg (165 lb). Their brains were larger than those of modern humans, but their brain structure differed in areas linked to thinking and language, which may explain why their behavior in the archaeological record seemed simpler than that of Cro-Magnons.

Neanderthals had small populations and faced challenges from inbreeding, which may have slowed their technological progress. They made stone tools called Mousterian, possibly wore blankets and ponchos, and may have used fire. Their diet included animals and plants found near their homes, often large game. Neanderthals often suffered serious injuries and attacks from animals. Some early art, such as bird claw and feather ornaments, unusual object collections, and engravings, have been linked to Neanderthals, but these findings are not certain. Neanderthals buried their dead, but there is no clear evidence they believed in life after death.

Taxonomy

Neanderthals are named after the Neander Valley, where the first known specimen was discovered. The valley was originally called Neanderthal, and the species was called Neanderthaler in German until 1901. In English, the species is sometimes spelled Neandertal, but the scientific name, Homo neanderthalensis, is always spelled with "th" because of a rule called the principle of priority. In German, the species is called Neandertaler, meaning "inhabitant of the Neander Valley," while Neandertal refers only to the valley itself. The valley was named after Joachim Neander, a German theologian and hymn writer from the late 17th century. His grandfather changed the family name from Neumann (meaning "new man") to Neander, a name inspired by the Greek word for "man."

The "th" in Neanderthal can be pronounced as /t/ (like in "tall") following German rules or as /θ/ (like in "think") in English.

Neanderthal 1, the first known specimen, was called the "Neanderthal cranium" or "Neanderthal skull" in scientific writings. The individual reconstructed from this skull was sometimes called "Neanderthal man." The scientific name Homo neanderthalensis was first proposed in 1863 by William King, an Irish geologist. He argued that Neanderthals were a distinct species from modern humans. However, in 1864, he suggested Neanderthals and modern humans should be classified in different genera because he believed their brains were more similar to those of chimpanzees than to humans.

Before scientists fully understood their age, many Neanderthal fossils were found. The first Neanderthal remains—Engis 2 (a skull)—were discovered in 1829 in Belgium by Philippe-Charles Schmerling. He believed these remains were buried at the same time as extinct animals. In 1848, a skull from Gibraltar, called Gibraltar 1, was found but was thought to belong to a modern human.

In 1856, a local teacher named Johann Carl Fuhlrott noticed bones from a site in the Neander Valley, later called Neanderthal 1, and gave them to Hermann Schaaffhausen for study. The bones included the cranium, thigh bones, arm, humerus, ulna, hip bone, shoulder blade, and parts of the ribs.

After Charles Darwin’s 1859 book On the Origin of Species, Fuhlrott and Schaaffhausen argued that Neanderthals were an early form of humans more closely related to apes and other human groups. However, Rudolf Virchow, a pathologist, opposed this, claiming that Neanderthals were not a distinct species and that their features were due to disease or aging. This slowed research until the early 20th century.

By the early 1900s, more Neanderthal fossils were found, proving Homo neanderthalensis was a valid species. Some scientists, like Gustav Albert Schwalbe, thought Neanderthals were a transitional stage between modern humans and apes. Others, like Marcellin Boule, described Neanderthals as ape-like creatures. Boule proposed two evolutionary lines in Ice Age Europe: one leading to modern humans and another ending with Neanderthals. As research shifted to East Asia in the 1930s and 1940s, the idea of a "Neanderthal phase" in human evolution was revisited.

In the 1970s, new methods like cladistics helped scientists better define species. This led to the reclassification of some Neanderthal-like fossils in Africa and East Asia as distant relatives of Homo neanderthalensis. The "Out of Asia" theory, which suggested modern humans originated in Asia, was replaced by the "Out of Africa" theory, which claims all modern humans share a common ancestor. Two main ideas followed: modern humans replaced other humans entirely or interbred with them. In 2010, the Neanderthal genome showed some interbreeding between Neanderthals and modern humans.

Neanderthals are classified as a unique species, Homo neanderthalensis, but some scientists suggest expanding the definition of Homo sapiens to include them. This debate is influenced by genetic evidence and Neanderthal behavior. While some genetic mixing occurred, signs of hybrid incompatibility might support their classification as a separate species.

Neanderthals are most closely related to Denisovans based on nuclear DNA. Denisovans are a mysterious group of humans known only through genetic evidence. Their mitochondrial DNA and Y-chromosome DNA are more similar to modern humans than to Neanderthals. Fossils from the Sima de los Huesos, dating to 430,000 years ago, share nuclear DNA with Neanderthals but have mitochondrial DNA more similar to Denisovans.

A 2021 study using tip dating analyzed the evolutionary relationships of Middle Pleistocene and Neanderthal fossils, including La Chapelle-aux-Saints 1.

Evolution

Neanderthal skull features first appear in European fossils from the early Middle Pleistocene, often found in remains classified as Homo heidelbergensis. These early humans, called "pre-Neanderthals," slowly developed Neanderthal traits ("Neanderthalization") as their populations adapted to cold climates, leading to a body type suited for very cold environments. Modern groups like the Inuit, who live in Arctic regions, are sometimes studied as examples of similar cold adaptations. During glacial periods, populations may have been forced into small areas, reducing genetic diversity and causing other Neanderthal traits to develop through genetic changes. The 120,000- to 140,000-year-old Nesher Ramla fossils in Israel may represent a group that later repopulated Europe after a major ice age.

Neanderthal traits varied widely even among individuals in the same group. The spread of these traits may have been slowed by gene exchange between Western Europe and Africa, as seen in some unusual fossils like Ceprano Man, which lack typical Neanderthal features. The first clear "early Neanderthals" appear in fossils by the end of Marine Isotope Stage 7 (around 243,000 years ago) and become more common by the end of Marine Isotope Stage 5e. This timeline covers the Penultimate Glacial Period to the Last Interglacial. Some early Neanderthal teeth from Payré, France, may date to MIS 8, but the dates are not certain.

Genetic evidence suggests Neanderthals separated from modern humans during the early Middle Pleistocene. Neanderthals and Denisovans are more closely related to each other than to modern humans, meaning their split happened later. Before this split, Neanderthals and Denisovans (called "Neandersovans") migrating from Africa interbred with an unknown "superarchaic" human group already in Europe. These superarchaics descended from an earlier African migration about 1.9 million years ago.

Genetic data shows Neanderthals had a small population with low genetic diversity after 100,000 years ago, which weakened natural selection and increased harmful mutations. It is unclear how long European Neanderthal populations faced this challenge or how much it influenced the development of Neanderthal traits.

Demographics

The Neanderthals were the first human species to live in Europe for a long time. Earlier Neanderthals are mostly found in Western Europe, but classic Neanderthals lived across Europe, as well as in Southwest and Central Asia, up to the Altai Mountains in southern Siberia. Pre- and early Neanderthals lived mainly in France, Spain, and Italy. Some groups moved eastward to create temporary settlements, but they did not leave Europe. However, southwestern France has the most Neanderthal sites from both early and classic times.

The southernmost Neanderthal remains were found in Shuqba Cave in the Levant. Earlier claims of Neanderthals in North Africa’s Jebel Irhoud and Haua Fteah have been corrected to show those remains belong to Homo sapiens. The easternmost Neanderthal remains were found in Denisova Cave in Siberia, near 85°E. A skull from Maba Man in southeast China shares some physical traits with Neanderthals, but these traits may have developed independently rather than Neanderthals living near the Pacific Ocean. The northernmost Neanderthal sites are generally thought to be near 55°N, with clear evidence from 50–53°N. However, it is hard to determine this because glaciers destroyed many remains. Middle Paleolithic tools have been found as far north as 60°N in Russia, but these are likely from modern humans.

Neanderthal range may have changed as ice sheets moved, with Neanderthals avoiding frozen areas and living in safe zones during cold periods. Areas with stable climates and mild yearly temperatures were likely the best places for Neanderthals to live.

Like modern humans, Neanderthals probably came from a very small group, with an effective population—meaning the number of people who could have children—of about 3,000 to 12,000. Neanderthals kept this small population size, which made it harder for natural selection to remove harmful genes. Archaeological evidence suggests the first Cro-Magnon population was about 10 times larger than Neanderthals.

Compared to Cro-Magnons, Neanderthals may have had a harder time growing their population because of lower birth rates or higher infant deaths, or both. In a study of 206 Neanderthals, about 80% of those older than 20 died before age 40. This high death rate was likely due to the tough conditions they faced. Infant deaths were also very common, with about 43% of babies in northern Eurasia dying before age one.

Anatomy

The Neanderthal skull has a flat and broad top, rounded brow ridges, wide eye sockets, a broad nose, and a face that sticks out from the base of the skull. When viewed from the back, the skull has a "bomb-like" shape. There is a depression on the back of the skull below the inion, and a bony bump called an occipital bun at the back. Like other early humans, Neanderthals did not have a true chin on their jaws.

The average brain size of Neanderthals was larger than that of modern humans. Males had an average brain volume of 1,640 cm³ (100 cubic inches), and females had 1,460 cm³ (89 cubic inches). The largest known Neanderthal brain, from a specimen called Amud 1, measured 1,736 cm³ (105.9 cubic inches), one of the largest ever recorded in humans. Differences in brain organization may have influenced Neanderthal behavior, which appears simpler compared to Cro-Magnons in the archaeological record.

Neanderthals had large, wide noses, likely an adaptation to warm cold air for their high energy needs. However, their smaller olfactory bulbs suggest they may have had a less developed sense of smell and memory compared to modern humans. Their cheekbones were strong, their front teeth were large and shovel-shaped, their molars had swollen tooth pulp, and there was a gap behind the molars. These features may have resulted from heavy use of the front teeth for chewing tough foods or using the mouth as a tool.

Neanderthals were not short and stocky, as often imagined. On average, they were the same height as pre-industrial Europeans or slightly taller. Their body mass index was similar to that of 20th-century Canadians and Americans. Body size varied by region, with West Asian Neanderthals being taller and more slender than European Neanderthals.

In a sample of 45 long bones from 14 men and 7 women, male Neanderthals averaged 164–168 cm (5 ft 5 in to 5 ft 6 in) in height, and females averaged 152–156 cm (5 ft 0 in to 5 ft 1 in). Adult Neanderthals ranged in height from about 147.5 to 177 cm (4 ft 10 in to 5 ft 10 in). The average male body mass index was 26.9–28.3.

Neanderthal pelvises were much wider than those of modern humans, with male hips about 31% wider. Both males and females had large pelvises relative to their body size, with larger males having the largest pelvises. Their chests were deep and wide, with a large thoracic cavity that may have supported stronger lung function. They had more fast-twitch muscle fibers and higher caloric needs. Their limbs were shorter than those of modern humans, a trait linked to adapting to cold climates. Their body structure may have made them efficient sprinters due to strong lungs, fast muscles, and shorter limbs.

Genes related to skin and hair color in modern non-African people suggest Neanderthals had varied pigmentation, including both lighter and darker skin and hair tones. Some Neanderthals had genes linked to red hair, but these were not common. These traits may have helped modern humans adapt to lower sunlight levels in Eurasia.

Neanderthals experienced a high rate of injury, with 79–94% of specimens showing healed major trauma. About 37–52% had severe injuries, and 13–19% were injured before adulthood. One example, Shanidar 1, had a missing arm, a bone infection, vision problems, and possible hearing loss. These injuries may have resulted from dangerous hunting practices or frequent animal attacks.

Low population numbers led to low genetic diversity and likely inbreeding, which reduced the ability to remove harmful mutations. It is unclear how this affected individual Neanderthals or whether it caused more birth defects than in modern humans.

Culture

It is hard to know how many Neanderthals lived together in a group, but clues suggest small groups of 10 to 30 people. These groups likely moved between caves depending on the season, as shown by remains of foods that were only available at certain times of the year. They returned to the same places for many generations, and some sites may have been used for over 100 years. Neanderthals may have competed with cave bears for space in caves. Groups may have been mostly led by males, with females from other groups joining for breeding.

Neanderthals had a small population across their range, which may have made it harder for them to trade over long distances or avoid inbreeding. They likely interacted often with nearby communities but not as much with those farther away. Genetic studies show there were at least three main groups: Western Europe, the Mediterranean coast, and areas east of the Caucasus, with some movement between these regions.

While Cro-Magnons are often thought to have divided tasks by gender—men hunting and women gathering—it is unclear if Neanderthals did the same. Both male and female Neanderthals show similar signs of injuries, which might mean both hunted. Their teeth show patterns that suggest men and women may have carried different items in their mouths, though these items may not have been related to food. At El Sidrón Cave in Spain, some female Neanderthals may have eaten more seeds and nuts than males. The lack of specialized tasks in Neanderthals is often linked to their small population and group size, which may have prevented the development of complex tools and behaviors.

Neanderthals were once thought to be scavengers, but they are now considered top predators. They mainly ate what was available nearby, leading to a wide variety of meats and plants in their diet, though the proportions changed based on location. In contrast, Cro-Magnons had more varied diets, even in areas where certain foods were hard to find. For example, Neanderthals in forests ate about the same amount of plant foods as Cro-Magnons, but Neanderthals on open plains ate far fewer plants.

In many European sites, remains of animals like red deer, reindeer, horse, aurochs, ibex, and steppe bison are found. Neanderthals in Southwest Asia hunted mountain gazelle, Persian fallow deer, wild goats, and camels more often. They may have hunted large animals like woolly mammoths and woolly rhinoceroses less frequently when these animals were common nearby. At a 125,000-year-old site in Germany, evidence suggests Neanderthals hunted straight-tusked elephants regularly, about every 5 to 6 years. Some groups near water ate fish, shellfish, dolphins, and Mediterranean monk seals. Neanderthals also hunted small animals like rabbits and tortoises, and at Gibraltar sites, remains of 143 different bird species were found, including ground-dwelling birds. They consumed a wide range of plants and mushrooms, with over 50 species found at Kebara Cave in Israel.

Neanderthals may have used many ways to prepare food. At Cueva del Sidrón in Spain, they may have roasted and smoked meat, and used plants like yarrow and camomile for flavor or medicine. At Gorham’s Cave in Gibraltar, they may have roasted pinecones to get pine nuts, and at Gruta da Figueira Brava, they softened crab shells before eating them. At Grotte du Lazaret in France, evidence suggests they hunted 23 red deer, 6 ibex, 3 aurochs, and 1 roe deer in a single autumn season, possibly to store meat for winter. At Neumark-Nord, they may have extracted fat from bones to reduce protein toxicity. Calcium measurements show Neanderthals at Grotte du Bison often ate bones.

Neanderthals competed with large carnivores like cave lions and wolves, and also hunted them, including cave and brown bears, even during hibernation. They sometimes avoided competition by hunting different prey, such as with cave hyenas and wolves. However, Neanderthals were often attacked by animals.

There are examples of Neanderthals practicing cannibalism, but this may have happened only during extreme food shortages, similar to some human groups in history.

Neanderthals collected unusual objects like shells, fossils, and gems. It is unclear if these were for decoration or had symbolic meaning. Some shells may have been painted. Researchers Clive and Geraldine Finlayson suggested Neanderthals used bird feathers as art materials. A 2020 study found a 3-ply cord made from tree fibers at Abri du Maras, France, which could be used for making strings. Perforated shell beads from Cueva Antón, Spain, may have been strung into necklaces.

There are many simple engravings and scratches on stones, bones, and pebbles. As of 2014, 63 such markings were found at 27 sites in Europe and the Middle East. It is unclear if these were symbolic. Neanderthals may have made finger flutings on cave walls in La Roche-Cotard over 57,000 years ago.

Neanderthals used ochre, a red clay pigment. It is not certain if this was for art, as modern humans also used ochre for medicine, tanning hides, preserving food, and repelling insects.

The Divje Babe flute, a 43,000-year-old cave bear bone from Slovenia, is sometimes linked to Neanderthals, but many researchers believe it was made by an animal chewing the bone.

Neanderthals made stone tools associated with the Mousterian industry, especially using the Levallois technique. After developing this from earlier Acheulean tools, there was little innovation for 150,000 years. This lack of progress may have been due to their small population, which limited the spread of new ideas. Neanderthals usually used materials from nearby sources, within about 5 kilometers. Some groups made tools from shells and bones, and may have attached spear tips to spears using birch bark tar. European Neanderthals also made wooden spears, like the 400,000-year-old Clacton Spear in Britain and the 300,000-year-old Schönin spear in Germany.

Interbreeding

The first Neanderthal genome sequence was published in 2010. This study showed that Neanderthals and early modern humans likely interbred. Neanderthal genes in modern humans came from at least two interbreeding events outside Africa. One event occurred about 250,000 years ago, and another happened between 40,000 and 54,000 years ago. Interbreeding also happened in other groups that are not ancestors of any living people today. People with ancestry outside sub-Saharan Africa may carry about 2% Neanderthal DNA. Sub-Saharan Africans may have Neanderthal DNA from a later migration back to Africa. Overall, about 20% of the Neanderthal genome appears to remain in modern human DNA. Most of this DNA comes from the children of modern human women and Neanderthal men. Many Neanderthal genes were likely removed from the human gene pool over time due to harmful effects (negative selection). Much of the remaining Neanderthal DNA does not have clear biological functions and is considered non-coding ("junk") DNA. However, some Neanderthal genes may help with metabolism, brain function, and development of bones and muscles. These genes may have helped early humans adapt faster, such as by improving immune responses.

Genetic evidence suggests that interbreeding mostly occurred between Neanderthal men and modern human women. This is supported by the lack of Neanderthal mitochondrial DNA (mtDNA) and lower Neanderthal DNA levels on the X chromosome. Scientist Svante Pääbo noted that it is unclear whether modern humans were socially dominant over Neanderthals, which may explain the pattern of interbreeding. A 2026 study confirmed that sexual selection, or a preference for Neanderthal males and modern human females, was the main reason for the uneven mating patterns, not differences in population size or migration.

Neanderthals in the Siberian Altai Mountains interbred with Denisovans, a related group. One Denisovan specimen from the Altai region had about 17% Neanderthal DNA.

Before genetic evidence confirmed this, scientists like Thomas Huxley (1890), Hans Peder Steensby (1907), and Coon (1962) suggested Neanderthals and early humans may have interbred. In the early 2000s, fossils like Lagar Velho 1 and Muierii 1 were thought to be hybrids. However, modern geneticists caution that some shared physical traits may have resulted from similar environments, not just interbreeding.

Extinction

The extinction of Neanderthals was part of a larger event in which many large animals disappeared during the Late Pleistocene. Neanderthals were replaced by modern humans, as shown by the change in stone tool technology across Europe. Older tools called Mousterian were nearly completely replaced by newer tools called Aurignacian, beginning around 39,000 to 41,000 years ago. In some areas, such as northern Spain, Mousterian tools may have lasted until about 39,000 years ago. In southern Spain and Gibraltar, they may have lasted until 32,000 to 35,000 years ago. Similar patterns of survival in small areas have been suggested in other regions like Italy, the Balkans, and Crimea.

In the past, some people believed Neanderthals and other early humans disappeared because modern humans, seen as more advanced, drove them out. This idea was sometimes tied to views that modern humans were superior.

The extinction of Neanderthals is often explained by competition with modern humans. Modern humans may have had advantages, such as larger populations, better movement over long distances, and more advanced tools and ways to find food. Some Neanderthals may have been absorbed into modern human groups instead of being outcompeted. This idea was supported by evidence of Neanderthal DNA in modern humans and by tools that show Neanderthals using techniques similar to modern humans, such as the Châtelperronian culture in France and Spain. Other unclear examples include the Uluzzian tools in Italy and the Szeletian tools in Central Europe.

Some scientists also suggest Neanderthals had small populations, which may have led to genetic problems that made them less able to adapt to changes in the environment or new diseases brought by modern humans. It is unclear if climate changes, like the cold period called Heinrich Event 4 or the Campanian Ignimbrite eruption, caused Neanderthals to leave certain areas. Modern humans may have been better at returning to these areas after such events. A time called the Laschamp event, between 39,000 and 42,000 years ago, may have increased harmful ultraviolet radiation. Neanderthals may have been more affected than modern humans, who may have used materials like ochre to protect their skin.

In popular culture

Neanderthals have appeared in many forms of popular culture, such as books, movies, and jokes. Often, they are shown as simple, bent-over, club-carrying, grunting figures who act on instinct and are not social. The word "Neanderthal" is sometimes used as a way to insult someone.

In books, Neanderthals are sometimes shown as violent or scary, like in The Grisly Folk by H. G. Wells and The Animal Wife by Elizabeth Marshall Thomas. Other books, such as The Inheritors by William Golding, Dance of the Tiger by Björn Kurtén, and Clan of the Cave Bear and the Earth's Children series by Jean M. Auel, describe Neanderthals as having a culture that is different from ours but not necessarily uncivilized.

References

1. After being mined for limestone , the cave caved in and was lost by 1900. It was rediscovered in 1997 by archaeologists Ralf Schmitz and Jürgen Thissen . [ 9 ]
2. The German /t/ phoneme was frequently spelled th from the 15th to 19th centuries until the German Orthographic Conference of 1901 . The German spelling Thal ("valley", a cognate of English dale ) changed to Tal , and the h was also dropped from Neandertal for the valley and Neandertaler for the species. [ 10 ]
3. In Mettmann , "Neander Valley", there is a local idiosyncrasy in use of the outdated spellings with th , such as with the Neanderthal Museum (but the name is in English [German would require Neandertalermuseum ]), the Neanderthal station (Bahnhof Neanderthal), and some other rare occasions meant for tourists. Beyond these, city convention is to use th when referring to the species. [ 10 ]
4. King made a typo and wrote "theositic".
5. The bones were discovered by workers of Wilhelm Beckershoff and Friedrich Wilhelm Pieper . Initially, the workers threw the bones out as debris, but Beckershoff then told them to store the bones. Pieper asked Fuhlrott to come up to the cave and investigate the bones, which Beckershoff and Pieper believed belonged to a cave bear . [ 9 ]
6. The X-chromosome carries far less archaic DNA than any autosome , which has either been explained as hybrid incompatibility (the large-X effect — background selection ) or male sex bias (hybrids were normally the children of a male Neanderthal and female modern human). [ 37 ]