Humans: Unusually Murderous Mammals, Typically Murderous Primates


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Humans: Unusually Murderous Mammals, Typically Murderous Primates

 

A new study looks at rates of lethal violence across a thousand species to better understand the evolutionary origins of humanity’s own inhumanity.

 

Which mammal is most likely to be murdered by its own kind? It’s certainly not humans—not even close. Nor is it a top predator like the grey wolf or lion, although those at least are #11 and #9 in the league table of murdery mammals. No, according to a study led by José María Gómez from the University of Granada, the top spot goes to… the meerkat. These endearing black-masked creatures might be famous for their cooperative ways, but they kill each other at a rate that makes man’s inhumanity to man look meek. Almost one in five meerkats, mostly youngsters, lose their lives at the paws and jaws of their peers.

 

Gómez’s study is the first thorough survey of violence in the mammal world, collating data on more than a thousand species. It clearly shows that we humans are not alone in our capacity to kill each other. Our closest relatives, the chimpanzees, have been known to wage brutal war, but even apparently peaceful creatures take each other’s lives. When ranked according to their rates of lethal violence, ground squirrels, wild horses, gazelle, and deer all feature in the top 50. So do long-tailed chinchillas, which kill each other more frequently than tigers and bears do.

 

The point of this macabre census was to understand the origins of our own behavior. Gómez typically studies plants and insects, but he realized that the techniques he uses to study their evolution can be used to study our own. In particular, he noted that closely related species tend to show similar levels of lethal interpersonal violence. He could use those similarities to predict how violent any given mammal should be, and whether it meets, exceeds, or defies those expectations.

 

Humans do all three. Gómez’s team calculated that at the origin of Homo sapiens, we were six times more lethally violent than the average mammal, but about as violent as expected for a primate. But time and social organizations have sated our ancestral bloodthirst, leaving us with modern rates of lethal violence that are well below the prehistoric baseline. We are an average member of an especially violent group of mammals, and we’ve managed to curb our ancestry.

 

Gómez’s team predicted that when our species arose, around 2 percent of us (1 in 50) would have been murdered by other people.

 

Thomas Hobbes would have approved. In the 17th century, he argued that modern society protects us from our brutish nature, lived in “continual fear, and danger of violent death.” Not so, said Jean-Jacques Rousseau, who felt that civilization corrupts our neutral nature. These opposing views on violence—the former emphasizing an innate proclivity, and the latter focusing on cultural influences—preceded Hobbes and Rousseau by many centuries, and outlived them by many more. “Consensus does not exist, and positions are polarized,” says Gómez. “We hope that our study will shed light to the role that both evolution and culture have played in human lethal violence.


First, he and his team compiled everything they could find on causes of death for various mammals, accumulating some 3,000 studies over two years. Their work revealed that lethal violence aimed at others from the same species is rare but widespread. It exists in almost 40 percent of the 1,024 mammal species that the team surveyed, and varies from group to group. Contrary to Watership Down, rabbits rarely kill each either. Neither do bats or whales. As you might expect, carnivores like lions, tigers, and bears, do so more frequently. But “it was striking that lethal violence wasn’t concentrated in those groups,” says Gómez.

 

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Continued...

 

 

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I am traumatized to see chinchilla's on that list.....brings back a haunting vision of the "killer rabbit" in Monty Python's "Search for the Holy Grail".

 

On another note....I see this as a "dialed in" instinct for survival.

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2 hours ago, astropheed said:

I would have been interested to see which mammals were the least likely to kill their own. I don't seem to see it in this article or the full one.

I'm thinking dolphins, whales, elephants and the even-toed ungulates in general, or any others that tend to live in herds and protect their offsprings in groups as family :) 

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