Bonobo Tracks Imaginary Objects in Pretend Play

Researchers have demonstrated for the first time that a bonobo ape can engage in pretend play by tracking imaginary objects, challenging the long-held view that such imaginative abilities are unique to humans. In experiments conducted in 2023 at the Ape Initiative in Des Moines, Iowa, the bonobo named Kanzi correctly identified the locations of nonexistent juice and grapes during simulated tea party scenarios, according to a study published Thursday in the journal Science.

Kanzi, who died in March 2024 at age 44, was renowned for his communication skills. Born in captivity in 1980, he learned to use lexigrams, symbols representing words, to interact with caretakers and respond to spoken English prompts. This training allowed him to understand several hundred symbols for objects and actions, making him a unique subject for cognitive tests. The experiments, led by Amalia Bastos of the University of St Andrews in Scotland and Christopher Krupenye of Johns Hopkins University, drew inspiration from child development studies where toddlers around age 2 or 3 follow imaginary liquids or objects during play.

In the first test, researchers placed two empty, transparent cups and an empty...