Neanderthals, or Homo neanderthalensis, are our closest extinct human relatives, having diverged from the lineage leading to modern humans at least 500,000 years ago. They inhabited a vast geographical expanse across Eurasia, from Portugal to the Altai Mountains of Siberia, adapting to diverse environments from temperate woodlands to the cold steppes of the last ice age. Fossil discoveries, beginning in Germany’s Neander Valley in 1856, have allowed scientists to piece together a nuanced picture of their existence. This evidence, including reconstructed genomes, reveals a sophisticated species that navigated the prehistoric world for a period far longer than Homo sapiens has existed.
Physical Characteristics and Anatomy
Neanderthal anatomy was adapted to the cold, arid climates of Pleistocene Europe and Asia. They had a stocky, muscular build with shorter lower legs and arms compared to modern humans. This robust physique, with a broad chest and pelvis, was effective at conserving body heat.
Their skulls housed brains that were, on average, larger than those of modern humans. The Neanderthal braincase averaged 1,640 cm³ for males and 1,460 cm³ for females, compared to the modern human average. However, the brain’s organization differed, with proportionally larger areas dedicated to vision and body control, likely adaptations to low-light conditions and their brawnier bodies.
Distinctive facial features also set Neanderthals apart. They had a long, low skull with a prominent, double-arched brow ridge above large eye sockets. Their faces featured a projecting mid-section and a large, wide nose, which likely helped warm and humidify cold, dry air. This structure, along with powerful jaws and large front teeth often used for gripping, differed from the flatter face of modern humans.
Daily Life and Culture
Neanderthals led complex lives marked by advanced tool use, skilled hunting, and symbolic behaviors. Their technological signature is the Mousterian tool industry, a method of stone tool production. This technology often involved the Levallois technique, a prepared-core method requiring forethought to produce sharp flakes for scrapers and points.
They were capable hunters, preying on large Ice Age animals like mammoths, woolly rhinos, and reindeer. Evidence suggests they were specialized seasonal hunters who used thrusting spears in close-quarters combat. Their diet was not exclusively meat-based, as analysis shows they also consumed various plants, nuts, grains, and marine resources like shellfish when available.
Evidence points to Neanderthals living in small, family-based groups. Within these social structures, they exhibited behaviors that suggest a capacity for symbolic thought. One of the most compelling examples is the practice of intentional burial. At sites like Shanidar Cave in Iraq, individuals were deliberately placed in graves, sometimes with offerings such as flowers.
Discoveries of personal ornaments and pigments also point to their cognitive depth. Neanderthals used black and red pigments like ochre, possibly for body painting or other symbolic applications. They also crafted simple jewelry from items like eagle talons and shells, demonstrating an awareness of symbolism and an aesthetic sense that reflects their cognitive depth.
Interaction with Modern Humans
As anatomically modern Homo sapiens expanded out of Africa, their journey led them into Eurasia, where they encountered established Neanderthal populations. For several thousand years, these two human groups coexisted, sharing parts of the landscape, particularly in Western Asia. Genetic evidence has definitively shown that their interactions were not limited to competition or avoidance; they also interbred.
The proof of this interbreeding lies within the DNA of people today. Analysis of the Neanderthal genome, first sequenced in 2010, revealed that populations outside of Africa carry traces of Neanderthal ancestry. Most modern non-African individuals have approximately 1-2% Neanderthal DNA.
This inherited genetic material appears to have had functional consequences for our species. Some of the Neanderthal genes that persist in the modern human gene pool are related to the immune system. These variants may have provided early modern humans with a quicker adaptation to the local pathogens and diseases prevalent in Europe and Asia.
Other inherited genes are linked to skin pigmentation and hair characteristics. Research suggests these traits could have been advantageous for Homo sapiens moving into the higher latitudes of Eurasia. While the full impact of this ancient interbreeding is still being explored, it is clear Neanderthals contributed a significant portion to the genetic makeup of non-African humanity today.
Theories on Extinction
The disappearance of Neanderthals around 40,000 years ago is a subject of scientific debate. It is widely believed that a combination of pressures led to their decline, which coincided with a period of rapid climate fluctuations and the expansion of modern human populations across Eurasia.
One factor was severe climate change associated with the last ice age. Abrupt shifts in temperature would have drastically altered the environments Neanderthals were adapted to, impacting the habitats of the large animals they relied on for food. While Neanderthals had survived previous climate extremes, the instability during this period may have placed their small, scattered populations under stress.
The arrival of larger groups of Homo sapiens introduced another challenge: competition. Modern humans may have possessed more efficient hunting technologies or more extensive social networks, giving them a competitive edge in exploiting limited resources. This competition could have been indirect, with modern humans simply out-competing Neanderthals for resources, or potentially more direct, though evidence for widespread conflict is scarce.
A final contributing factor may have been assimilation through interbreeding. As Neanderthals encountered larger modern human populations, they were gradually absorbed into the much larger Homo sapiens gene pool. Over time, this process could have led to the dilution of their distinct genetic lineage until they no longer existed as a separate group.