Murders are in the news so frequently
that you may quietly wonder: are people just
naturally violent?
We can answer that question by
looking at the rest of the animal kingdom.
Are we Homo sapiens any more murderous than, say,
monkeys, mice, or meerkats?
[Music]
A team of researchers in Spain found out
by gathering data for more than one thousand
mammal species, and they found that
killing is actually pretty rare.
Okay sure, predators will eat prey,
but less than half of the studied species kill members
of their own kind.
And we humans are nowhere near
the top of the chart of the most murderous mammals.
We’re not even in the top 30.
Some of those top species include obvious
ones: predators like lions, bears, and wolves.
But the list has surprises too.
Cute things like ground squirrels, wild horses, deer.
The adorable long-tailed chinchilla
is sitting at number 14.
And at the number 1 most murderous mammal?
The meerkat.
They might seem lovable, but around 20 percent
of meerkats lose their lives to other meerkats.
Primates, the group we belong to,
turn out to be an unusually violent bunch.
They are 8 times more likely to kill
each other than other mammals are.
This makes sense: Primates are both
territorial and social, two factors that provide
the motive and opportunity for murder.
So we descend from a group of unusually
murderous mammals.
But what’s happened since then?
To find out, the Spanish team combed through
archeological data and historical records.
They found that in paleolithic times,
lethal violence caused 3.5% of all human deaths,
making our ancestors only slightly more violent
than the average primate.
But as our societies got bigger,
our rates of lethal violence increased, rising to around
12% during the Medieval period.
But, once we formed large states
and became more organized, institutions and the rule
of law reduced rates of murder,
which are now much lower than in our prehistoric past.
The philosopher Thomas Hobbes would have approved.
In the 17th century, he argued that modern society
protects us from our brutish nature.
Not so, said Jean-Jacques Rousseau,
another philosopher who believed that humans
are naturally good, and civilization is what corrupts us.
So did Hobbes win this age old debate?
Well maybe, but there's a catch.
Some researchers argue that how a mammal species
kills its own kind matters more than the rate
at which it does the killing.
And for primates, the most common MO is infanticide.
They kill their babies.
But what makes humans so different is that
we kill each other as adults
at an exceptionally high rate.
It is adult homicide that makes us part of
a very small club of violent mammals that
includes the like of wolves, lions, and spotted hyenas.
Human violence may be rooted in our evolutionary past,
and we may tamed our lethal proclivities,
but like it or not, when it comes to violence,
humans are still exceptional.
This is You Are Here, a new series from the Atlantic
about the science behind everyday life.
Let us know what topics you want us to explore
in the comments.
I’m Ed Yong, thanks for watching.