Below is an old video of Koko the Gorilla, when she was 13. She mourned when her pet kitten has died.
The grieving gorilla understands sign language she learned from the researchers at the Gorilla Foundation in California. This non-profit organization was created by Francine Patterson, who is a long-term trainer of Koko.
The female gorilla received a pet kitten named All Ball for her birthday when she turned 13. But unfortunately, All Ball was hit by a car and died.
Watch how Koko the Gorilla cries upon learning the sad news.
[embedyt]https://www.youtube.com/watch?v=CQCOHUXmEZg[/embedyt]