In addition to many millions of humans, at least one other primate is likely mourning the loss of actor and comedian Robin Williams today. Koko, the gorilla who communicates in a modified version of American Sign Language and is said to understand even some spoken words, filmed an ad campaign with Williams in 2004 to raise awareness of threats against gorillas. The video below shows their first meeting, where Koko asks Williams to chase and tickle her, steals his sunglasses, and rummages through his wallet:
According to an article from Business Wire, Williams said afterwards: "Meeting Koko was unforgettable. Koko used sign language to ask me to play with her. We shared interspecies laughter." Dr. Penny Patterson, the researcher who has worked with Koko for more than 40 years, said about the meeting, "Koko instantly connected with Robin. Koko, like us, can sense a person's nature and in this case, she was quickly drawn to Robin's warm heart."
Oh, and that comment about Koko perhaps mourning Williams' death was not a joke. In the mid-1980s, Koko’s pet cat, All Ball, wandered from the Gorilla Foundation in California onto a nearby highway and was struck by a car and killed. Ronald Cohen, co-founder of the foundation with Patterson, said at the time, "When we told Koko, she acted like she didn't hear us for about 10 minutes. Then she started whimpering—a distinct hooting sound that gorillas make when they are sad. We all started crying together."