by David Cantor

In the aftermath of mass murders, as in Las Vegas, we constantly hear that killing others arises from human nature. Filmmaker Ken Burns stated in his “Fresh Air” interview about his recent release on the Vietnam War, “War is human nature in spades.”

Yet, during my 28 years studying human beings’ killing of others, I discovered this from the leading expert on training human beings to kill in war, psychologist Lt. Col. Dave Grossman, in “On Killing: The Psychological Cost of Learning to Kill in War and Society,” “[D]espite an unbroken tradition of violence and war, man is not by nature a killer.” Grossman invokes findings that even with military training and indoctrination, many soldiers deliberately fire over the enemy’s head.

As consistently indicated in a great many sources on morality in human beings and other animals, we see human nature in the altruistic, protective, compassionate, and cooperative behavior that takes hold in the aftermath of mass murder, in mass resistance to war, and in spontaneous celebration of war’s end.

This distinction is crucial for understanding and preventing violence and murder and for responding to perpetrators. If killing were natural, we would not collectively be so horrified by it. Maybe it would be OK for authorities to “lie us into war” if “we” could benefit at the expense of “them.” Instead, we experience moral injury from our representative government’s promoting official violence while demonizing killers acting on their own.

We reward and celebrate peacemakers and officers who make arrests without killing or injuring the accused. We teach children how to get along with other human beings, not how to kill them because it is “natural” to do so.

For killing to manifest an animal’s biological nature, the animal must have body parts adapted to killing other animals and to protecting against prospective victims’ defenses. It helps to have thick, tough skin; long, hard claws and powerful muscles for wielding them; long fangs and strong jaw and head muscles to sink them between a victim’s vertebrae; back and limbs especially suited to pouncing and chasing.

Obviously, human beings do not possess such physical traits.

As detailed in “The Comparative Anatomy of Eating” by Milton R. Mills, M.D., human beings have none of the anatomical or physiological traits that define animals who evolved in nature to kill other animals – the above plus an omnivore’s or carnivore’s dentition, saliva, and digestive tract. In nature, killing is mostly for eating. No naturally occurring human “equipment” correlates with that function.

Humans evolved as plant-foraging apes on the African savanna, with color vision good for distinguishing a great variety of edible leaves, fruits, berries, flowers, and other plants that eventually led to what we call “produce” when our species began living unnaturally through agriculture; versatile digits and nails adapted to picking, plucking, peeling; teeth good for tearing and grinding plants – not for ripping and scarfing flesh.

Human beings’ organized killing relies on innovation, not nature – on manufactured weapons, traps, rope and, more recently, poison, electrical current, toxic fumes. For killing, our elaborate imaginative and cooperative capabilities, adapted to avoiding predation and raising families while moving about the landscape foraging for plants to eat, are distorted to plan and coordinate assaults, attacks, murders, wars, eliminationist campaigns, and executions.

Our bodies alone – our original, natural condition – aid us in spotting our natural predators, grabbing children and fleeing, defending with rocks and tree branches, not in actively planning, organizing, and setting out to kill.

In making policies and establishing practices with regard to nonhuman animals, human beings and governments typically analyze the kind of animal involved. Except that other animals’ sentience, emotions, and intelligence are denied because our innate humaneness rebels against injuring and killing.

It is peculiar indeed that we craft policies and perpetuate practices for our own species based on ignorance of such a basic fact of our animality as whether or not it is natural for us to kill.

A native Chestnut Hiller and 1973 graduate of Springside Chestnut Hill Academy, David Cantor is founder and director of Responsible Policies for Animals, in Glenside – www.RPAforAll.org.