​Koko, born Hanabiko on July 4, 1971, captivated the world with her remarkable ability to communicate using a modified form of American Sign Language (ASL). Her name, meaning “fireworks child” in Japanese, commemorates her Independence Day birth. Under the guidance of caregiver Francine “Penny” Patterson, Koko mastered over 1,000 signs, demonstrating advanced cognitive abilities. 

Beyond her linguistic skills, Koko exhibited behaviors indicative of deep emotional understanding. She formed a profound bond with a kitten named All Ball, treating it as her own offspring. Tragically, when All Ball died, Koko expressed grief through signs and vocalizations, underscoring the depth of her emotional capacity. ​

Koko’s interactions extended to notable human figures as well. She shared a memorable connection with television personality Fred Rogers, famously removing his shoes upon meeting him, mirroring a ritual from his show.

Her ability to discuss past events and emotions challenged prevailing notions about animal cognition and language. Koko’s legacy continues to inspire efforts in animal communication research and conservation.