Born on October 28, 1980, Kanzi was raised at the Language Research Center at Georgia State University, where scientists spent a few years trying to teach his adoptive mother, Matata, to communicate using symbols called lexigrams. However, while Matata failed to master the art of language, researchers were stunned when a young Kanzi spontaneously began using the lexigram board to talk to them.

According to Dr Sue Savage-Rumbaugh – who cared for Kanzi throughout most of his life – Kanzi successfully communicated more than 120 times on his first day of observation and eventually developed a vocabulary of around 3,000 words. Subsequent studies indicated that most of his multi-word phrases were spontaneous, suggesting that he was capable of creatively combining concepts to compose novel sentences.

For instance, Savage-Rumbaugh has recounted how Kanzi once invented the phrase “bad surprise” to describe a prank he had played on a researcher. He also once threatened to bite one of his carers, before apologizing several months after making good on his promise.

One study even found that Kanzi outperformed a human toddler at understanding and complying with complex commands, and researchers eventually realized that he often vocalized the phrases he spelled out with lexigrams – albeit in unintelligible bonobo speak.

According to the ACCI, Kanzi “is regarded as the first great ape to demonstrate an understanding of spoken English.” 

“Kanzi comprehends novel sentences and combines lexigram symbols to describe new objects and foods,” explains the research center. During his time at the facility – which was previously managed by the Great Ape Trust – the famous bonobo made global headlines on multiple occasions, such as when he appeared on a popular YouTube channel playing Minecraft. 

Despite his remarkable skills and achievements, however, Kanzi’s linguistic capabilities remain a topic of debate among researchers, some of whom believe the famous bonobo’s habits amount to communication rather than language, much like Koko the gorilla could “talk” using sign language. 

Announcing Kanzi’s unexpected death, the ACCI said that he appeared to be “his normal, happy self” on the day of his passing, and “did not exhibit any signs of discomfort or illness.” After spending the morning foraging for breakfast and playing with his nephew Teco, Kansi then lay down for a grooming session with another bonobo, at which point he became “unresponsive”.

“Although we will not know the cause of death until we receive the necropsy results, Kanzi was being treated for heart disease, and he participated in regular ECGs and blood pressure monitoring,” says the ACCI.

“We are focused on ensuring Kanzi’s bonobo family members and human caregivers receive the care and support that they need,” adds the research center. “We ask for time and patience as we grieve the passing of our dearest friend, Kanzi.”