However, Koko's story takes a poignant turn when her beloved pet kitten, All Ball, died. Koko was deeply affected by the loss, exhibiting signs of grief, such as sadness, agitation, and a decrease in appetite. Dr. Patterson and her team were able to provide Koko with emotional support and comfort, demonstrating the importance of understanding animal behavior and emotional intelligence.

As Koko grew older, she began to experience health issues, including a decline in her vision and arthritis. Dr. Patterson worked closely with veterinarians to ensure Koko received the best possible care, including regular check-ups, medication, and a specialized diet.

Over the course of 40 years, Dr. Patterson and her team observed and interacted with Koko, gaining insights into the gorilla's emotional and social behavior. They discovered that Koko was capable of learning over 1,000 signs, exhibiting complex problem-solving skills, and even displaying empathy and compassion towards humans and other animals.

The study of Koko's behavior and health highlights the critical role of veterinary science in animal welfare. By understanding animal behavior, veterinarians can diagnose and treat medical conditions more effectively, improving the quality of life for animals in their care.

For example, research on animal behavior has informed conservation efforts for species such as elephants, chimpanzees, and wolves, helping to mitigate human-wildlife conflicts and promote coexistence.

In the 1970s, Dr. Francine "Penny" Patterson, a renowned animal psychologist, began working with Koko, a western lowland gorilla, at the San Francisco Zoo. Dr. Patterson's goal was to teach Koko American Sign Language (ASL) to understand the gorilla's cognitive abilities and behavior.