Study: Innately murderous humans becoming less so

Evolution and genetics seem to have baked a certain amount of murder into humans as a species, but civilization has tamed some of the savage beast in us, according to a new study.

Scientists calculated the rate at which more than 1,000 mammal species kill their own kind, and noticed how closely related species have similar rates of lethal violence.

As a group, mammals average a lethal violence rate against their own of about three killings of their own species in 1,000 deaths. The “root” violence rate of early humans and many of our closer primate cousins is about 20 in 1,000, said study lead author Jose Maria Gomez at the University of Granada in Spain. But in the medieval period, between 700 and 1500 A.D., that deadly rate shot up to about 120 per 1,000.

But we’ve gotten less murderous.