The keepers would give the gorillas an assortment of fruits and vegetables each afternoon, and on this particular occasion, Judy Sievert tossed Nina an apple, which rolled away. Instead of going to get it, Nina just 'sat there sadly,' in Judy's words. Judy continued her rounds, handing out yams and apples to the other gorillas, but Nina sat there looking appleless and downtrodden. Taking pity, Judy tossed her another apple. As soon as Nina had it, she got up and went over to where the first apple had rolled away, taking it too.
Eugene Linden, The Parrot's Lament, and Other True Tales of Animal Intrigue, Intelligence, and Ingenuity
animals, deception, gorillas