Santino evidently knows he's going to get upset, so he plans ahead.
The 30-year-old chimpanzee, who has lived in a Swedish zoo most of his life, sometimes gets agitated when zoo visitors begin to gather on the other side of the moat that surrounds his enclosure, where he is the dominant -- and only -- male in a group that includes half a dozen females.
He shows his displeasure by flinging stones or bits of concrete at the human intruders, but finding a suitable weapon on the spur of the moment perhaps isn't so easy. To prepare, Santino often begins his day by roaming the enclosure, finding stones and stacking them in handy piles.
Read the whole story...there's a great picture of Santino.