Robin Williams touched people around the world with his sense of humor — people who were shocked and saddened Monday by news of his death.
But he wasn't only mourned by people.
In 2001, Robin Williams was invited to meet Koko, the gorilla who communicates in sign language, at the Gorilla Foundation in northern California.
"We had no idea what to expect," Koko's handlers posted on koko.org, "but everyone was in for a treat, and they became very special friends."
On Tuesday, Koko overheard Dr. Penny Patterson, her mentor and surrogate mother, talking on the phone about Williams' death. "She became extremely sad," her handlers wrote.
Koko.org uploaded video of the 2001 meeting, noting that it was the first time Koko had smiled since her childhood gorilla companion Michael had died six months earlier.
"Robin's ability to just 'hang out' with Koko, a gorilla, and in minutes become one of her closest friends, was extraordinary and unforgettable," they wrote."
"When you remember Robin Williams, remember that he is not only one of the world's most beloved entertainers, he is also one of the world's most powerful ambassadors for great ape communication."