At first, the footage might make people squeamish, in the sense that Koko is so big, and the kittens so small. "Careful, Koko!" viewers must mutter nervously. But Koko is as gentle as can be, handling the first kitten she meets with the delicacy she might reserve for a baby of her own kind.
Koko's language gifts are well documented. She understands more than 1,000 hand signs, and she knows some 2,000 spoken English words, as the Telegraph notes. Now the primate wordsmith has "has adopted these two kittens into her family, and it has energized her world," the Gorilla Foundation, which houses Koko, writes on its Youtube channel.
Koko now seems to be communicating through signs with her caregivers even more frequently than she was prior to meeting her new feline friends. Such two-way communication "can have significant benefits to both endangered free-living great apes and those in captive environments," the organization adds.
Fans of Koko's may also remember her interaction with Robin Williams, and her sadness at the news of his death. Here she is with the late, legendary comedian: