Santino, a 30-year old chimp who lives at a Swedish zoo, hates gawkers. So in his spare time, when the zoo his closed, he methodically gathers rocks from the moat in his enclosure. When the zoo opens, he becomes enraged and throws the rocks at the visitors.
Scientists are calling this the first proof of an animal planning for a future event (the arrival of zoo visitors). Of course, the obvious plain-as-day observation here is that perhaps Santino’s behavior indicates that it’s inhumane to keep chimps in zoos. But somehow that insight appears to have eluded the researchers and journalists who’ve written about Santino. Link.