Sign language isn't the only unusual thing about Koko. She's also been a pet-owner. In 1983, at the age of 12, researchers said that Koko asked for a cat for Christmas. They gave Koko a toy cat. Koko was not happy. She did not play with it, and she continued to sign sad. So for her birthday in 1984, Dr. Patterson allowed Koko to pick up a cat from the street. She picked up a gray cat and named him "All Ball." Dr. Patterson said that Koko loved All Ball as though he was a baby gorilla. Sadly, All Ball got out of Koko's cage and was hit by a car.

Sign language isn't the only unusual thing about Koko. She's also been a pet-owner. In 1983, at the age of 12, researchers said that Koko asked for a cat for Christmas. They gave Koko a toy cat. Koko was not happy. She did not play with it, and she continued to sign sad. So for her birthday in 1984, Dr. Patterson allowed Koko to pick up a cat from the street. She picked up a gray cat and named him "All Ball." Dr. Patterson said that Koko loved All Ball as though he was a baby gorilla. Sadly, All Ball got out of Koko's cage and was hit by a car.

This part describes Koko's experience with a pet cat named "All Ball." It highlights her initial dissatisfaction with a toy cat, her adoption of a real cat, her affection for it, and the tragic end of the cat's life.