When did humans first go to war?

When modern humans arrived in Europe around 40,000 years ago, they made a discovery that was to change the course of history.

The continent was already populated by our evolutionary cousins, the Neanderthals, which recent evidence suggests had their own relatively sophisticated culture and technology. But within a few thousand years the Neanderthals were gone, leaving our species to continue its spread to every corner of the globe.

Precisely how Neanderthals became extinct remains a subject of fierce debate among researchers. The two main explanations given in recent years have been competition with the recently arrived modern humans and global climate change.

The persistence of Neanderthal genetic material in all modern people outside of Africa shows the two species interacted and even had sex. But it’s possible that there were other kinds of interactions as well.

Some researchers have suggested that competition for resources such as prey and raw materials for stone tools may have taken place. Others have proposed violent interactions and even warfare took place, and that this may have caused the Neanderthals’ demise.

This idea might seem compelling, given our species’ violent history of warfare. But proving the existence of early warfare is a problematic (although fascinating) area of research.

War or murder?

New studies keep moving the threshold at which there is evidence for human warfare progressively earlier. But finding such evidence is fraught with problems.

Only preserved bones with injuries from weapons can give us a secure indication of violence at a given time. But how do you separate examples of murder or a family feud from prehistoric “war”?

To an extent, this question has been resolved by several examples of mass killing, where whole communities were massacred and buried together at a number of European sites dating to the Neolithic period (about 12,000 to 6,000 years ago, when agriculture first emerged).

For a while, these discoveries appeared to have settled the question, suggesting that farming led to a population explosion and pressure for groups to fight. However, even earlier instances of group killing suggested by the bones of hunter gatherers have re-opened the debate.

Defining warfare

A further challenge is that it is very difficult to arrive at a definition of war applicable to prehistoric societies, without becoming so broad and vague that it loses meaning. As social anthropologist Raymond Kelly argues, while group violence may take place among tribal societies, it is not always regarded as “war” by those involved.

For example, in the dispensation of justice for homicide, witchcraft or other perceived social deviance, the “perpetrator” might be attacked by a dozen others. However, in such societies acts of warfare also commonly involve a single individual being ambushed and killed by a coordinated group.

Both scenarios essentially look identical to an outside observer, yet one is regarded as an act of war while the other is not. In this sense, war is defined by its social context rather than simply by the numbers involved.

A key point is that a very particular kind of logic comes into play where any member of an opposing group is seen as representing their whole community, and so becomes a “valid target”. For example, one group might kill a member of another group in retribution for a raid that the victim wasn’t involved in.

In this sense, war is a state of mind involving abstract and lateral thinking as much as a set of physical behaviours. Such acts of war may then be perpetrated (usually by males) against women and children as well as men, and we have evidence of this behaviour among skeletons of early modern humans.

Fossil record

So what does all this mean for the question of whether modern humans and Neanderthals went to war?

There is no doubt that Neanderthals engaged in and were the recipients of acts of violence, with fossils showing repeated examples of blunt injuries, mostly to the head. But many of these predate the appearance of modern humans in Europe and so cannot have occurred during meetings between the two species.

Similarly, among the sparse fossil record of early anatomically modern humans, various examples of weapon injuries exist, but the majority date to thousands of years after the Neanderthals’ disappearance.

Where we do have evidence of violence towards Neanderthals it is almost exclusively among male victims. This means it is less likely to represent “warfare” as opposed to competition between males.

While there is no doubt Neanderthals committed violent acts, the extent to which they were capable of conceptualising “war” in the way it is understood by modern human cultures is debatable. It is certainly possible that violent altercations could have taken place when members of the small, scattered populations of these two species came into contact (although we have no conclusive evidence for such), but these cannot realistically be characterised as warfare.

Certainly, we can see a pattern of violence-related trauma in modern human skeletons from the Upper Palaeolithic period (50,000 to 12,000 years ago) that remains the same into the more recent Mesolithic and Neolithic times. However, it is not at all clear that Neanderthals follow this pattern

On the bigger question of whether modern humans were responsible for the extinction of Neanderthals, it’s worth noting that Neanderthals in many parts of Europe seem to have gone extinct before our species had arrived. This suggests modern humans can’t be completely to blame, whether through war or competition.

However, what was present throughout the period was dramatic and persistent climate change that appears to have decreased the Neanderthals’ preferred woodland habitats. Modern humans, although they had just left Africa, seem to have been more flexible to different environments and so better at dealing with the increasingly common colder open habitats that may have challenged Neanderthals’ ability to survive.

So although the first modern Europeans may have been the first humans capable of organised warfare, we can’t say this behaviour was responsible or even necessary for the disappearance of Neanderthals. They may have simply been the victims of the natural evolution of our planet.

Martin Smith receives funding from Bournemouth University.

John Stewart receives funding from Bournemouth University.