Something that's...

On July 4th of 1971, a baby western lowland gorilla was born at the San Francisco Zoo.

She was named Hanabi Cole, which means fireworks child in Japanese.

But she became known by her nickname, Coco.

Little baby Coco was pretty sick for the first year of her life,

so she spent a lot of time at the Zoo's medical center.

But soon, Coco's life would radically change, once she met Francine Penny Patterson.

Together, it captured the public imagination as explored in this PBS documentary.

Here's Penny.

That first day that we actually got to see her...

She was kind of feisty.

She ran around and gave me a nip on the ankle.

In 1972, Penny was a 20-something PhD psychology student at nearby Stanford University.

She was interested in primary communication.

What do you want to be when you grow up? Talked to monkeys.

Said no one ever, except Penny.

Chimpanzees, but no bow and gorillas.

There are closest living relatives and Penny wanted to know if she could teach a gorilla to communicate with humans.

Gorillas don't use their voices the same way as humans do,

so Penny, like some researchers before her, decided to try to teach Coco sign language.

In 1972, Penny started Project Coco, a research project to teach Coco how to communicate using sign language.

Penny visited Coco at the zoo every day and started teaching Coco basic signs.

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