Spain — As a species, humans have inherited very violent traits, including the capacity to kill each other, according to a new study from the University of Granada in Spain published in the journal Nature.
Researchers studied murder rates of more than one thousand mammal species and found out that closely related species show similar tendencies. Humans are “particularly violent” thanks to our evolutionary tree. The average murder rate for mammals is of three killings per every 1,000 deaths. Meanwhile, the average murder rate for early humans and the closer primates in the evolutionary tree was of twenty killings per every 1,000 deaths.
In the Medieval period, murder rates increased exponentially to 120 killings per every 1,000 deaths, reaching the pinnacle of the human capacity for violence.
Thanks to civilization, humans are less violent
Modern humans have a killing rate of thirteen killings per every 1,000 deaths, according to José María Gómez, lead author of the study. Researchers used data from the World Health Organization as a basis for their calculations.
However, is more accurate to say that “violence has decreased significantly in the contemporary age” since many technical variables are affecting the exact numbers.
Killer whales have a rate of murder of almost zero, and so do many species of anteaters and bats, concluded the research. Certain species of baboons, chinchillas, and lemur, have rates of more than one hundred killings per 1,000 deaths, making them way more violent than the modern human being.
The research was based on the theory of phylogenetics and the study of the evolutionary relationships and shared traits between related species. The closer the studied species were, the more similar their murder rates were, concluded the study.
Scientists analyzed more than one thousand previous studies that referred to over one thousand different mammal species. They particularly investigated causes of death. Then, the researchers compared the number of fatalities related to murder.
A superorder of species known as Euarchontogilires has a murder rate of about eleven killings per 1,000 deaths. Rodents, hares, and early humans are part of this order. The Euarchonta group, which includes primates, flying lemurs, and humans have a rate of twenty-three killings per 1,000 deaths. For great apes, the rate is eighteen killings per 1,000 death.
The research concluded that modern violence depends on government and culture, and it can be reversible. It can also increase or decrease according to social factors.
“Based on three biological facts — we are apes, we are social and we are territorial — one would predict that humans should engage in lethal violence in our natural conditions. Modern societies have developed, especially the rule of law, that has reduced rates of deadly violence below what would expect for a mammal with our ancestry and ecology,” stated Steven Pinker, author of the book The Better Angels of Our Nature.
Source: National Geographic