It all started in 1974 when Penny Patterson, then a graduate student at Stanford University, adopted Koko from the San Francisco Zoo as part of her Ph.D. research in psychology. The zoo agreed to let Penny take Koko, who at the time was just a baby, under one condition — that she commit to caring for Koko for at least four years.

Fast-forward 41 years and Penny and Koko are still together and going strong! The reason Penny adopted her in the first place was to see if it was even possible for a gorilla to learn sign language. And if it was possible, how much could be learned about their cognitive abilities through direct communication, according to Koko’s official website.

The similarities between primates, gorillas especially, and humans has been a constant topic of conversation. How similar are we really? Is it possible to communicate with gorillas?

I think it’s safe to say that Koko has broken boundaries and shed a new light on human-gorilla relationships. Through Penny’s care and training, Koko has learned how to use more than 1,000 signs and seems to understand about 2,000 spoken English words. Not only that, Koko understands these signs well enough to be able to combine them to express new meanings she wants to communicate.

Considering we’ve never been able to communicate with gorillas, let alone any type of animal species, that is simply remarkable! Koko’s awe-inspiring and fascinating life has made her somewhat of a celebrity as well.

She was able to meet and befriend Robin Williams in 2001 (she was heartbroken after his death) and she’s also been able to meet one of her other favorite celebrities — Mr. Rogers!

In the video below you’ll see Koko and Mr. Rogers meet for the first time and it’s absolutely amazing. When you’re watching it, you almost forget Koko is a gorilla, that’s how well she communicates!

Koko asks Mr. Rogers about his cufflinks and talks to him about love. Watch their adorable interaction below and be sure to SHARE the love and pass it on!