Malice aforethought

A chimp who made a breakthrough in the science of bad animals is back in the news.

As we reported previously, Santino had a habit of throwing stones at zoo visitors, but this was not just the usual spontaneous primate poop-throwing sort of thing: He gathered ammunition when no one was watching and hid caches of it around his exhibit. What's more, he didn't bother to collect these secret supplies when the zoo was closed to visitors over the winter.

It seemed obvious to many that he was gathering the stones to be ready to throw them at people, so Santino was used as an argument that animals can plan for the future, one of the many abilities that our species likes to claim are uniquely human.

But scientists, like everyone else, are reluctant to believe that animals deliberately behave badly, so some were still skeptical. Sure, he made piles of stones, but maybe he had collected them for some other reason, and they just happened to be at hand when he got the urge to hurl something.

But now researchers have reported additional evidence for Santino's carefully planned deception. First he learned to look innocent: instead of screaming and displaying his anger, he might just walk by munching on an apple, and then make his surprise attack.  And now, he's concealing the stones in ways that let him get closer to his victims before he throws them: for example, he'll place a pile of hay near where visitors hang out and use it to hide some stones. He's also used logs for the same purpose.

This behavior is new since the original research was reported. Perhaps once his fame spread, people knew not to get close when he was holding rocks, so he was inspired to new heights of deception.

Some scientists are still quibbling. But now, Santino, sensible people aren't coming near one of your hay piles. You're going to come up with something else new, and we'll be watching.