War between Neanderthals and modern humans was one of the main causes of the Neanderthal extinction.
The other factors also used to explain the extinction of Neanderthals include parasites and pathogens, competitive replacement, interbreeding with humans, natural catastrophes and a failure to adapt to climate change.
It was probably a combination of these factors that led to the extinction of the Neanderthals, but it would seem that there is increasing evidence to suggest that Neanderthal wars with modern humans was one of the main reasons for the extinction of the Neanderthals.
There is increasing evidence for a war between Neanderthals and modern humans around 600 000 years ago which led to the extinction of the Neanderthals after the Hominids split in two groups as one group stayed in Africa, evolving into modern humans, whilst the other migrated to Asia and Europe where they evolved into Neanderthals.
Before they became extinct, Neanderthals were cooperative big game hunters and ever since the earliest discoveries of Neanderthal remains there have been theories that they were war-like in the same way as modern humans.
Neanderthals also shared many other traits with modern Humans like making fire, burying their dead as well as making artwork and building stone shrines.
Prehistoric Archaeology has unearthed Homo Sapien and Neanderthal Skulls with evidence of blunt trauma to the skull. Other evidence of warfare between modern Humans and Neanderthal include skeletons which show a lot of broken Neanderthal arms and chest wounds.
The injuries suffered by Neanderthals also indicate a prolonged guerilla ambush war with modern humans which lasted for about 100 000 years before war with modern Humans made Neanderthals extinct.
The Human-Neanderthal Wars were fought over land to ensure sufficient territory to hunt and forage for food. The extinction of the Neanderthals due to war with modern Humans was a long war of attrition.
Its not exactly clear when and why modern Humans gained the upper hand in the War with the Neanderthals, but in 120 000 years all the Neanderthals in Asia and Europe had been eliminated.
One of the most interesting explanations for why the humans won the war against the Neanderthals is that modern Humans were a better organised Hunter-Gatherer Society which enabled them to build larger Clans and armies than the Neanderthals.
When the Ancient Astronaut hypothesis is considered we are confronted with the possibility that modern humans triumphed because they were more intelligent and skilled in the Arts of War as the offspring of the Anunnaki Ancient Astronaut Alien Gods that had bred and trained Homo Sapiens for working and fighting.
In the final analysis, there are many possible reasons, the Neanderthals became extinct. However, the war hypothesis in terms of which the Neanderthals were exterminated over a long period of time in a guerilla war with modern humans over competition for territory stands out as one of the most likely reasons for the extinction of the Neanderthals.