Gorilla Kept Stacking Tires Every Morning — Then His Caretaker Finally Figured Out Why

In doing so, Koko showed remarkable memory recall, a major sign of intelligence. He was essentially creating semblances of order and symmetry within his own surroundings. For Francine, it was a moment of sheer joy-she discovered that Koko was mirroring human behavior, not just understanding it but mimicking it too.