As you report, Steve Ross, a primatologist at Lincoln Park Zoo in Chicago, has shown that gorillas are far from gentle giants, as was commonly believed (“Reputations in the Mist,” March 28, 2009). Just like the other apes, they, too, hunt animals for food. The research has also shown that bonobos, previously believed to be but sex-crazed vegetarians, are the most aggressive apes of all. They regularly hunt animals for food. In short, this sort of behavior is far from limited to our closest relatives, the chimpanzees, which have long been known to be aggressive killers. Perhaps there is some consolation here, after all, for all of our close relatives are now known to be pretty vicious. In a way, this takes us off the hook.