Kanzi the Bonobo: A Legacy of Redefining Ape Intelligence

Kanzi, the renowned bonobo who revolutionized our understanding of ape intelligence, has passed away at the age of 44. His life and accomplishments challenged deeply ingrained beliefs about the chasm separating humans from our closest relatives, leaving an indelible mark on primatology and animal cognition research.

Kanzi died on March 18 in Des Moines, Iowa, at the Ape Cognition and Conservation Initiative, a research organization dedicated to the study and preservation of bonobos. While the exact cause of death is pending autopsy results, those close to him noted he appeared in good spirits on the day he died, engaging in typical bonobo behaviors such as chasing other members of his group, foraging, and grooming. However, Kanzi was being treated for heart disease, and given that the average lifespan of bonobos is around 40 years, his passing, while deeply felt, was not entirely unexpected.

"Kanzi means so much to so many people. Our team is absolutely devastated by Kanzi’s passing,” the Ape Initiative shared in a statement. “A favorite among his bonobo family members, Kanzi was a friend to everyone.”

Kanzi’s significance extends beyond mere scientific observation; he stands as a legend within the realm of great apes – a group that encompasses chimpanzees, bonobos, gorillas, orangutans, and humans. His remarkable aptitude for language, his capacity for toolmaking, and his evident zest for life have cemented his place as one of the most influential nonhuman minds ever studied. His insights have profoundly shaped the perspectives of researchers and advocates alike, prompting a reevaluation of the very definition of intelligence and sentience.

Born in captivity in 1980, Kanzi began his life at the Yerkes Field Station in Georgia, now a part of the Emory National Primate Research Center. At the age of five, Kanzi, along with his sister Panbanisha, moved to Georgia State University’s Language Research Center. Later, the siblings were relocated to the Great Ape Trust in Des Moines, Iowa. This facility, once a hub of groundbreaking research, faced challenges and controversy, ultimately closing its doors after Panbanisha’s death in 2012 amidst allegations of animal mistreatment and operational issues. The Ape Initiative resurrected the site in 2013, stepping in to manage operations and continue crucial research.

While earlier experiments demonstrated the potential for apes to learn sign language, as seen with Koko the gorilla and Washoe the chimpanzee, Kanzi distinguished himself through his ability to communicate using symbols and comprehend spoken English. This unique ability challenged traditional views on the cognitive limits of nonhuman primates.

Primatologist Sue Savage-Rumbaugh, a key figure in Kanzi’s development, guided him through the complexities of language using a keyboard adorned with geometric symbols known as lexigrams. Working at the Great Ape Trust, Savage-Rumbaugh asserted that Kanzi eventually grasped the meanings of approximately 3,000 spoken words, an astonishing feat that demonstrated the potential for receptive language skills in bonobos.

In the 1990s, archaeologists Nicholas Toth and Kathy Schick from Indiana University collaborated closely with Kanzi, teaching him to make and use stone tools using techniques reminiscent of early human tool production. Kanzi not only replicated these methods but also began to develop his own distinctive approaches to flaking stones. This offered unprecedented insights into the cognitive and motor skills required for prehistoric toolmaking, further blurring the lines between human and ape abilities.

The Great Ape Trust provided Kanzi and his fellow apes with a stimulating environment. The facility was equipped with amenities such as drinking fountains, hydraulic doors that the apes could operate themselves (effectively making them gatekeepers, as humans required a "buzz" to enter), a kitchen stocked with a vending machine and a microwave oven, and even a recreation room with a TV and VCR. Kanzi developed a fondness for films like Clint Eastwood’s "Every Which Way But Loose" (featuring the orangutan Manis), along with "Quest for Fire," "Greystoke: The Legend of Tarzan," and "Babe." These preferences hint at the apes’ capacity for entertainment and perhaps even an appreciation for narratives.

Kanzi’s engagement with technology extended beyond passive viewing. He was also a gamer. In 2006, a bootlegged NHK YouTube video surfaced, revealing Kanzi skillfully and enthusiastically playing Pac-Man. Savage-Rumbaugh, in correspondence about the video, stated that the extensive documentation of Kanzi’s behavior in diverse and natural settings underscored the authenticity of his capabilities. The experience proved to be a pivotal moment for many, including inspiring increased advocacy for animal rights and the promotion of nonhuman animal personhood.

More recently, Kanzi demonstrated an enthusiasm for the video game Minecraft, documented by YouTuber Christopher Slayton in 2023. Amanda Epping, a research coordinator at the Ape Initiative, told the Des Moines Register that Kanzi enjoyed the game and thrived on the attention he received from an audience cheering him on. "It’s fun for him, it’s mentally stimulating," Epping explained, noting that Kanzi’s "ability to learn new skills within minutes of us showing him was truly incredible, he could understand what needed to be done in Minecraft within just a few attempts of the task." This showcased not only his cognitive flexibility but also his capacity for sustained engagement with complex tasks.

Kanzi’s legacy transcends the realm of scientific curiosity. He stands as tangible evidence that the artificial distinctions we draw between human and nonhuman intelligence are far more tenuous and indistinct than previously conceived. His life challenges us to reconsider our anthropocentric biases and to embrace a more inclusive understanding of intelligence and sentience. As we reflect on Kanzi’s extraordinary life, it becomes increasingly evident that the gulf between humans and our fellow apes is not as vast as we often assume. He leaves behind a world more open to acknowledging the complex minds of our primate relatives.