Koko the Gorilla mourning Robin Williams

Rico thought it a joke (if in poor taste) when he first saw it, but Ellie Hall has a Buzzfeed article that says it's the truth:

“Koko instantly connected with Robin,” said Dr. Penny Patterson, the foundation’s president and the gorilla’s foster mother. “Koko, like us, can sense a person’s nature and in this case, she was quickly drawn to Robin’s warm heart.”
The actor, who would later describe the meeting as “unforgettable”, filmed a PSA in 2004 with Koko for the Gorilla Foundation, to raise awareness of environmental threats to the species. Williams also accepted the post of honorary co-chair for the foundation’s campaign to create the Maui Ape Preserve.
Koko was with Patterson when news of Williams’ death broke and phone calls started to come in. After the first call, Koko came to Dr. Patterson with an inquiring look on her face. Dr. Patterson explained (via sign language, as Koko 'speaks' Ameslan) that ‘we have lost a dear friend, Robin Williams’.” “Koko was quiet and looked very thoughtful,” a spokesperson for the Gorilla Foundation said in a press release.

Rico says his cats would hardly notice he was gone, until dinner time...