Via Jonathan Stein, a 30-year-old chimp named Santino living in a Swedish zoo has learned a fiendish new trickā€”he'll stockpile an arsenal of carefully chosen rocks that he can later fling at his captors (and other gawkers) as soon as the zoo opens:

On some days, he's barraged visitors with up to 20 projectiles thrown in rapid succession, always thrown underhand. Several times he has hit spectators standing about 30 feet across a water-filled moat. ...

The animal's preparations include not only stockpiling stones he finds, but more recently also fashioning projectiles from pieces of cement that have broken off artificial rocks in his habitat.

"Many animals plan. But this is planning for a future psychological state. That is what is so advanced," said Mathias Osvath, the director of the primate research station at Lund University and author of the paper in the journal Current Biology. ...

"People always assume that animals live in the present. This seems to indicate that they don't live entirely in the present," said Frans de Waal, a primatologist at Emory University in Atlanta, who was not involved in the research.

Very clever. Though I suppose it's not much longer 'til the rest of the chimps learn this trick and we have a real war on our hands. Don't say you weren't warned.

--Bradford Plumer