In 1971, student Penny Patterson met a baby gorilla called Koko at San Francisco Zoo. She never imagined that this animal would form the defining relationship of her life. Forty-four years on, Koko lives in the same mobile home she grew up in – a compound near the Stanford University campus. Patterson lives nearby.


In the ensuing years, she claims to have taught Koko how to speak through American Sign Language. The gorilla has even, apparently, developed a crush on Benedict Cumberbatch.

Now 70, Patterson spends her days with Koko, observes her on live camera feeds when she’s away, and stays up late at night preparing meals for her. Their bond, remarkably, is not unlike that of a mother and child. But, as is explored in a new BBC1 documentary, the long-term welfare of human-imprinted apes – as animals like Koko are known – and the humans close to them, is far less Doctor Dolittle than it might seem.

The relationship between Koko and Patterson originally began as an experiment. Age one, the western lowland gorilla was loaned to Patterson for her doctoral research, and has stayed with her ever since. After starting with symbols for “eat”, “drink”, and “more”, Patterson claims Koko can understand over 1,000 signs, and use them to construct phrases of her own.

“What can be so startling is that because she’s been brought up with people, she has similar mannerisms, similar gestures, and you do feel that there’s a familiarity that you wouldn’t normally expect to have with an animal,” says the documentary’s producer, Bridget Appleby.

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“You feel like you’re on the same level of communication, even without the sign language.”

But there is a downside: Koko is confused about her own identity, and according to Appleby doesn’t see herself as a gorilla. “She sees Penny as her mother, so doesn’t really understand that she should be associating with gorillas; she thinks she should be associating with people.”


She also displays sexual attraction to humans – Appleby was advised by Patterson to bring an attractive male cameraman with her – and has even developed a love for English accents. This love was forged, says the producer, during sittings for renowned artist Richard Stone, who has done portraits of the Queen and Duke of Edinburgh. And in recent years the gorilla has also become attracted to the voice of Benedict Cumberbatch through the DVDs viewed in her home. “Apparently she has a big crush on him,” says Appleby. “She loves English men.”

Koko’s lack of a baby is understood to be the great sadness of her
life. When asked if she has
any regrets, Patterson admits, tearfully: “Not giving Koko a baby. She wants to be a mama.” She goes on to reflect on Koko’s life: “It wasn’t her choice, it was mine. It was an opportunity that was amazing, but it doesn’t mean it’s the best thing for her. She’d be more fulfilled if we’d been successful building a family group here.”

What about Patterson’s own life? She never married and never had children. “I think I was made for what I’m doing,” she says. But can she ever have intended to form a lifelong attachment?

“I think it’s haunted her, that feeling of guilt that she took Koko away from her own species, and she’s spent her life trying to make it right for her,” says Appleby. “A 70-year-old should have a bit of time to herself; I think Penny has the sort of life you live once you’ve got a newborn baby and that must make it hard for her to keep everything in perspective.”

The central issue of whether apes can learn sign language is in dispute, with experts claiming that results of studies are inconclusive, and that Patterson in particular may give Koko too many prompts to substantiate her claims. But Patterson defends the life she’s given Koko. “She’s not a pet. But the fact that Koko can love, that we can love each other even though we’re different species, really gets people thinking deeply about life. And that’s what we need to do.”


Koko: the Gorilla Who Talks to People premieres Wednesday at 8:30pm on BBC1.