Staff at the Furuvik Zoo in Sweden first became suspicious in 1997 when they spotted multiple stone piles at the park's "chimpanzee island" where Santino lives, explained Osvath, a Lund University researcher in the field of cognitive science.
Now having read through this far, I can already predict this is not going to end well. You know, like in Michael Crichton's Congo, with the flat discs of rock...
A caretaker performed surveillance by hiding herself behind a blind to investigate what was going on.
Don't DO IT! FOR GOD'S SAKE STAY OUT OF THERE!
"Stone throwing toward a crowd of people has an instant and dramatic effect," Osvath wrote, "and was a way to evoke reactions across the water moat that enclosed the chimpanzee."
And you think the chimp is smart enough to establish a missile cache, but not smart enough to cross the moat?
Santino is the lone male on the island, which he has shared with multiple females over the years. The females "seem to show little interest in the stone caches and concrete disc manufacturing."
So the chimp has all the females to himself, and he's still MANUFACTURING CONCRETE DISCS TO HURL AT HUMANS.
Chimps may not even be the only animals that feel compelled to attack humans with rocks from time to time.
Oh no, it's spreading.
Move along. Nothing to see here.