If you've ever spent time watching chimps at the zoo…

If you've ever spent time watching chimps at the zoo, you've probably 1: what are they thinking? Well, the answer might be simple: could be they're fixin'to hurl a rock at your head. One chimp in Sweden actually hides stones and other potential projectiles, and then acts casual before chucking them at visitors— behavior that suggests an 2 degree of primate planning and deception. His duplicity is 3 in the journal Public Library of Science ONE. The chimp, named Santino, had long been known to fling things at 4 onlookers.For years he's calmly gathered stones and chunks of 5, stacking them in piles, which he visits when some human particularly irks him. But lately Santino has gotten more cunning. For one, he's taken to concealing his arsenal 6 little heaps of hay that he carries out from his enclosure. And his attacks are also more stealthy. Santino used to pitch a fit before pitching a stone. But now he acts all nonchalant, even thoughtfully munching an apple before letting the missiles fly. The researchers say the data show that chimps are capable of social planning and deception. Unless, of course, that's just what the chimps want us to think.