He’s just had to sit through his offspring’s fourth birthday party, with the youngster tearing open his presents and jumping all over daddy’s head in his excitement. So I can understand the expression of weariness on Kanzi’s face when I ask him what he wants for lunch.

Then someone mentions the word ‘omelette’ — a Kanzi favourite, not just to eat but even to cook — and he’s off. He clambers on to a ledge in the viewing room of his concrete, steel and glass home and positions himself in front of a large, touch-sensitive computer screen showing a grid of some 400 symbols, or ‘lexigrams’, each representing a particular object or idea.

A huge forefinger skims dextrously over the icons, pressing the ones he wants. The computer voices his selections with an American accent.

This remarkable creature is a superstar. For years he has been changing the way we humans think about our relatives in the animal world, and challenging our assumed superiority to them.

The bonobo is a more gentle and intelligent cousin of the chimpanzee. Its only natural homeland is now the Democratic Republic of Congo. Bonobos are our closest animal relative (sharing about 99 per cent of our DNA) and physically resemble our distant ancestors.

Kanzi, now 33, has been fully immersed in the human world, and the English language, since birth. Scientists who have studied Kanzi all his life say he possesses a vocabulary big enough to follow and contribute to simple conversations.

He can cook, make knives out of stone and play the arcade game Pac-Man (he can get past the first round — a feat beyond many humans). He and his similarly talented late sister, Panbanisha, once even jammed with British rock star Peter Gabriel, playing along on a keyboard as the former Genesis man played a synthesizer.

Kanzi loves chatting on the video-calling service Skype. Two days later, I hear from him. Kanzi wants to see my home and particularly the contents of the fridge.

In Swahili, Kanzi means ‘buried treasure’ — a quality this creature has in buckets.