The stone throwing chimp

Much discussion about the chimp who seems to have stored stones, planning his attacks on people visiting the zoo he is in:

There has been scant evidence in previous research that animals can plan for future events.
Crucial to the current study is the fact that Santino, a chimpanzee at the zoo in the city north of Stockholm, collected the stones in a calm state, prior to the zoo opening in the morning.
The launching of the stones occurred hours later - during dominance displays to zoo visitors - with Santino in an "agitated" state.
This suggests that Santino was anticipating a future mental state - an ability that has been difficult to definitively prove in animals, according to Mathias Osvath, a cognitive scientist from Lund University in Sweden and author of the new research.
"We've done experimental studies, and the chimps in my mind show very clearly that they do plan for future needs, but it has been argued that perhaps this was an experimental artefact," Dr Osvath told BBC News.
"Now we have this spontaneous behaviour, which is always in some sense better evidence."
Cracking show

Good for Him ! But the fact is he is agitated when he throws them and given that i'd hazard a guess that he doesn't like being imprisoned in an enclosure being gawped at by people for their entertainment and would much rather have his freedom in the wild.