Clever Monkey

Here's the basic story, and here is the original article.

This is the summary. Zoo keepers at Furuvik Zoo in Sweden have discovered that a chimpanzee which annoyed visitors by throwing stones at them was in fact making a coherent and thought-through plan for the future: they found lots of piles of stones on the creature's island, and then observed the animal gathering stones so that it would have ammunition when the visitors it wanted to frighten away turned up. This proves that chimpanzees have the capacity, previously thought to be only human, to plan for the future. This story pleased me.

Then the aftermath: in order to calm the chimpanzee down and stop it throwing rocks at people, they cut its balls off. This doesn't please me so much.