The gorilla, who is known for her extensive sign language abilities, picked out two kittens to bring up as her babies.
Koko the gorilla got a special treat for her 44th birthday: a box of kittens to cuddle.
In a heartwarming video, the gorilla, who is known for her extensive sign language abilities, gently picked the kittens out from the box, which was presented to her by the Gorilla Foundation in Redwood, California.
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"Koko's maternal instincts turn on when she sees the kittens and cradles them in her arms," the foundation said on its website.
In the video, she uses sign language to ask her trainer to place one of the kittens on her head, and the trainer obliges.
She was allowed to adopt two of the kittens from the litter and they will now live with her. The organization named them Ms. Gray and Ms. Black.
"Koko has adopted these two kittens into her family, and it has energized her world," the foundation said.
This isn't the first time Koko has been a surrogate mom. In 1985 she asked for a pet and was given two kittens, whom she looked after for 10 years until they passed away.
The Gorilla Foundation says Koko has learned to use more than 1,000 signs and understands 2,000 spoken words. She's part of a research project studying non-human communication. The organization also aims to study the emotional awareness of gorillas.
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