A male chimp in Sweden has stirred excitement by storing a cache of stones to hurl at visitors, the BBC reports. Santino, a chimpanzee in a zoo north of Stockholm, proves that animals can prepare for future events, said scientist Mathias Osvath. "These observations convincingly show that our fellow apes do consider the future in a very complex way," he told the AP.
Osvath began studying Santino after zoo staff found his stone supplies 12 years ago. What impressed Osvath most—beyond Santino's "highly developed consciousness"—was his tapping of water-weakened portions of concrete to pull out pieces of rock. Other studies have suggested consciousness in apes, but "now we have this spontaneous behaviour, which is always in some sense better evidence," said Osvath.