The Natural Predatory Nature of Humans
A study published in Nature shows us that both evolution and genetics have made a big
impact on the behavior of humans…including in the case of murder. However, as we
have become more civilized, these instincts have been muted.
Scientists have looked at the rate of homicide in more than 1,000 species, and they
noticed something interesting: The rates of these lethal acts are similar, which means
that evolution of each species can give us a good idea of how violent each species
This study states that humans are part of a violent group of similar mammals. These
mammals all evolved at the same time, together. Plus, all of these mammals have
murderous and violent pasts. So, what does this mean for us? It means that we are
violent today because our ancestors were violent.
When you look at all mammals, about three in 1,000 are murderers. However, when you
specifically look at humans, the average over time is about 20 in 1,000. Furthermore,
when you examine certain time periods, such as the medieval period, this rate rose to
about 120 murderers in 1,000. These numbers have fortunately fallen, however, and
today, it stands at about 13 murderers per 1,000 people.
So, we are killing each other much less frequently today than we used to 1,000 years
ago. However, we are still not as peaceful as other mammals. For instance, killer
whales, which we believe to be quite violent, have a murder rate of almost zero against
their own species.
We are much more violent than whales, but when we compare our murder rates to
those of cougars, baboons, or lemurs, we are less violent. All of these animals have a
murder rate of about 100 per 1,000.
Since this research looked at violence by comparing species that are closely related, it
is not surprising that these species are similarly violent. It is also interesting that the
more closely related a species is, the more similar their instances of violence.
It’s quite difficult to actually calculate the rates of violence among our ancestors, but we
are able to get a good idea thanks to archaeological evidence. It was found that by
looking at these sites, that violence rates were lower among people who had some type
of government or culture. This also suggests that murder rates among a species can be
reversed. In fact, this evidence shows that it can decrease or increase based on
ecological, cultural, or social factors. This evidence is similar to what was found in a
study done at Harvard, which specifically looked at violent crimes including rape and
When looking at these facts, we find that humans are territorial and social, but also
naturally violent. As we have developed over time and found more civilized activities,
our rates of violence have gotten lower. What’s even more interesting is that most
mammals aren’t murderers towards their own species…but some, such as lions,
wolves, and primates, which includes humans, engage in violent actions.