Bonobo’s ‘Pretend Play’ Hints at Ape Imagination | Science News

For years, scientists have pondered the question of imagination in animals, often considering it a uniquely human trait. Now, a new study suggests that bonobos, our close evolutionary relatives, may possess a capacity for make-believe, challenging long-held assumptions about animal cognition. The research, published February 5, 2026 in the journal Science, centers around a bonobo named Kanzi, who demonstrated an ability to track imaginary objects in a controlled experiment.

The study, led by Dr. Amalia Bastos of the University of St. Andrews in Scotland and Dr. Christopher Krupenye of Johns Hopkins University, adapted experimental techniques commonly used with human children to assess Kanzi’s understanding of pretense. Researchers presented Kanzi with a scenario involving imaginary juice. They pretended to pour juice from an empty pitcher into two transparent cups, then pretended to pour the contents of one cup back into the pitcher. When asked which cup still contained the “juice,” Kanzi correctly identified the cup with imaginary juice 68% of the time – a statistically significant result, indicating he wasn’t simply guessing.

“What’s really exciting about this work is that it suggests that the roots of this capacity for imagination are not unique to our species,” said Dr. Krupenye.

To rule out the possibility that Kanzi was simply responding to residual scents or visual cues, the researchers also conducted a control test using actual juice. In this scenario, Kanzi chose the cup containing real juice almost 80% of the time, demonstrating his ability to differentiate between the real and the imagined. A similar experiment involving imaginary grapes placed in jars yielded comparable results.

Kanzi’s story is remarkable. He was raised in a lab environment and became proficient in communicating with humans using lexigrams – graphic symbols representing words. He could combine these symbols to create new meanings and even learned to create simple stone tools. This unique upbringing and cognitive ability made him an ideal subject for exploring the complexities of animal imagination.

Prior anecdotal evidence hinted at potential imaginative play in apes. Researchers had observed chimpanzees in the wild carrying sticks as if they were infants, and captive chimpanzees dragging imaginary blocks after playing with real ones. However, these observations were difficult to interpret definitively, as the apes could have been imitating researchers or misinterpreting objects. The current study provides the first rigorous experimental evidence supporting the idea that apes can engage in pretense.

The ability to understand and engage in pretense is considered a crucial cognitive skill in humans, underpinning creativity, problem-solving, and social interaction. It allows us to envision possibilities beyond the immediate reality and to build complex mental models of the world. The fact that bonobos demonstrate a similar capacity suggests that this ability may have deep evolutionary roots, potentially dating back to our common ancestor, which lived between 6 and 9 million years ago, according to Dr. Bastos.

However, not all scientists are fully convinced. Dr. Michael Tomasello, a comparative psychologist at Duke University, argues that there’s a distinction between simply tracking an imaginary object and truly engaging in pretense. “To be convinced of that I would need to see Kanzi actually pretend to pour water into a container himself,” he wrote in an email. Dr. Tomasello, who was not involved in the study, suggests that the current experiment demonstrates an understanding of pretense, but not necessarily the active creation of a pretend scenario.

Kanzi’s unique upbringing raises questions about the generalizability of these findings. Having grown up closely interacting with humans, his cognitive abilities may have been shaped by this environment. It remains unclear whether similar levels of imaginative play would be observed in bonobos living in the wild.

Kanzi passed away last year at the age of 44, but his legacy continues to inspire further research into the minds of apes. Many great ape species are currently facing critical endangerment, making it increasingly important to understand their cognitive capabilities. “Kanzi opened this path for a lot of future studies,” said Dr. Bastos, highlighting the potential for ongoing research to unravel the mysteries of animal imagination and cognition.

This research adds to a growing body of work suggesting that the cognitive landscape of apes is far more complex than previously thought, and that the boundaries between human and animal intelligence may be less distinct than we once believed.