Great Apes Know Just How Much to Annoy One Another
In the late aughts, while working on the island of Jersey, in the United Kingdom, Erica Cartmill found herself staring at a daughter giving her mother some grief.
The little one was waving a stick in her mother’s face and then yanking it back when her mother reached to snatch the object away—a performance so persistent, so targeted, Cartmill told me, that it was almost impossible for the grown-up to ignore. Cartmill was immediately reminded of kids threatening to poke each other in the back seat of a car. Only, the pair she was watching weren’t human: They were an orangutan and her two-year-old, lazing about in the straw at the island’s local zoo.
At the time, Cartmill didn’t know how to parse what she’d observed. She was wrapping up her Ph.D. on gestural communication in great apes, but this
