A western lowlands gorilla named Koko, famous for having learned a simplified form of American Sign Language (ASL), died in her sleep at her Californian reserve earlier this week at the ripe old age of 46.

The gorilla's talent for communicating has intrigued primate researchers, but it was her human-like affection, intelligence, and love of kittens that really captured our hearts.

Her birth in San Francisco Zoo on Independence Day, 1971, inspired her full name of Hanabiko – fireworks child in Japanese.

By her first birthday her caregiver, animal psychologist Francine "Penny" Patterson, was already showing her how to use her hands to communicate basic ASL signals.

It's not clear how many hand signs Koko learned to understand during her lifetime, with speculation that they exceeded 1,000.

While researchers have debated the limits of Koko's abilities to comprehend the symbols in terms of complex language, few doubt that she was able to string the words together effectively to convey her desires, her griefs, and possibly even a sense of humour.

She reportedly mastered at least one universal symbol – an extended middle finger that would be recognised virtually anywhere in the western world.

It was this human connection that made Koko more than just a study subject. She was a media celebrity.

Koko has been the subject of documentaries, books, and numerous studies. In 2012 she was observed to learn to play – crudely, mind you – a woodwind instrument.

Her mastery of the recorder might not have sold records, but it did challenge thinking on how non-human primates can learn to modify their breathing.

Her connection with an adopted kitten she named All Ball made headlines in 1984, when Koko learned her beloved pet was struck by a car and killed.

Cat, cry, have-sorry, Koko-love, came the signs. And then, Unattention, visit me.

Now it's our turn to mourn Koko.

Gorillas can live for thirty to forty years in the wild, though in captivity can live into their fifties. So 46 years of kittens, music, and celebrity interviews wasn't at all bad for a gorilla.

Cry. Have-sorry, Koko.