Bonobo Named Kanzi Plays Pretend in Groundbreaking Study

A bonobo just shattered a belief scientists have held for generations: that only humans can imagine things that aren't really there.

Meet Kanzi, a 43-year-old bonobo living at Ape Initiative who became the first ape to pass controlled tests for pretend play. Researchers at Johns Hopkins University designed tea party experiments to see if Kanzi could track imaginary objects, and the results surprised everyone.

In the first test, an experimenter pretended to pour invisible juice into two clear cups, then emptied one. When asked "Where's the juice?" Kanzi consistently pointed to the cup that should still contain the pretend liquid. He kept answering correctly even when researchers moved the cups around.

The team wanted to make sure Kanzi truly understood the difference between real and pretend. In a second experiment, they offered him one cup with actual juice and one with imaginary juice. Kanzi picked the real juice almost every time, proving he knew the pretend juice wasn't actually there.

A third test used imaginary grapes instead of juice. Again, Kanzi successfully tracked where the experimenter pretended to place invisible grapes in jars. While he didn't answer perfectly every time, his accuracy was consistently better than random guessing.

The Bright Side

This discovery means imagination might go back 6 to 9 million years to the common ancestor humans share with bonobos and chimpanzees. Co-author Christopher Krupenye, an assistant professor at Johns Hopkins, says the finding invites us to reconsider what makes humans special.

"It's extremely striking and very exciting that the data seem to suggest that apes, in their minds, can conceive of things that are not there," said co-author Amalia Bastos, now lecturing at the University of St. Andrews. Kanzi can generate an idea of a pretend object while knowing it isn't real.

The research, published in Science on February 5, opens doors to studying whether other apes and species can engage in pretend play. Scientists are now curious about whether apes can imagine future events or think about what others might be thinking.

Human children start playing make-believe around age two, hosting tea parties and caring for dolls. Researchers had seen hints of pretend behavior in wild chimps and captive apes before, but this marks the first controlled proof that apes can truly understand pretense.

Krupenye says the discovery transforms our understanding of animal minds: imagination is no longer a uniquely human trait, and other creatures may have richer mental lives than we assumed.