Every morning, Santino, an apparently aptly-named 31-year old chimpanzee, methodically collects rocks and literally stock-piles them in anticipation of visitors arriving at the Stockholm zoo. And when said visitors do arrive, Santino begins angrily hurling the stones at the unsuspecting gawkers.
This seemingly unprecedented complex anti-social behavior confirmed researchers suspicions that - just like humans - apes are capable of preparing for future.
A future that - if the chimps get their way - will probably look a lot like this.
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