Rock Throwing Chimp shows planning behavior. His reward? Read on, Folks.

WHEN Santino the chimpanzee started pelting zoo visitors with stones, his keepers were mystified. Not that they were surprised by his displays of aggression -- the 31-year-old chimp is, after all, a dominant male. But there was no obvious source of stones in his enclosure; so where was he finding all the missiles? All became clear when they carried out a search and found his stockpiles of rocks. Santino had been fishing stones from the moat surrounding his enclosure

Researchers have found what they say is some of the first unambiguous evidence that an animal other than humans can make spontaneous plans for future events. The report in the March 9th issue of Current Biology highlights a decade of observations in a zoo of a male chimpanzee calmly collecting stones and fashioning concrete discs that he would later use to hurl at zoo visitors.

The Furuvik Zoo has gone to some lengths to stop Santino's attacks on visitors. "Sometimes they will keep him in during the morning, and only let him out once the visitors have arrived," Osvath told the New Scientist. "It's very hard to stop him because he can always find new stones, and if he can't find them he manufactures them. It's an ongoing cold war."

Finally, the zoo decided to neuter the chimp in an attempt to curb his aggressive behavior. The surgery was performed late last year, but staff won't know if it's succeeded in calming him until the summer months, which is when Santino normally exhibits his rock-throwing behavior.