Why is it, when we're confronted with the details of a particularly savage crime - of cold, calculating cruelty - we label such behavior as inhuman?

To call some monstrous behavior inhuman seems almost an insult to animals.

Certainly no dog or cat ever intentionally put out cigarettes on their offspring's legs. Herds of zebras don't band together and kick herds of gazelles to death, much less gas and shoot 6 million Jews to death. No king of the jungle was ever barbaric enough to abduct and recruit into martyrdom 10,000 Iranian children, who in the 1980s were thrown across minefields into the line of Iraqi fire, with a little key to paradise round their necks.

Nature is red in tooth and claw. But its redness is related to hunger and survival, not hatred and racism. The great killers of natu…