Among the millions mourning the death of Robin Williams on Monday was Koko, a gorilla who communicates in sign language. Williams met Koko in 2001 at The Gorilla Foundation in Northern California, where the great ape managed to upstage the great comedic actor.  “Years later (on Aug. 11, 2014), Koko overheard Penny (Dr. Penny Patterson, Koko’s mentor and surrogate mother) talking on the phone about Robin, who had just passed away,” The Gorilla Foundation stated on its website. “She became extremely sad.”