Swing and Doll have not forgotten what happened many years ago. The only 23-year-old Koebner came as a student to the experimental laboratories, where the two were kept together with four other chimpanzees in miserable conditions.
As babies, they had been locked in tight boxes without natural light. Hepatitis medication was tested on them for six years. At that time it was common to kill chimpanzees after their time as experimental animals.
But it was decided to release them into the wild, which they still had to get used to.
That is why Lisa Koebner spent the following years in close community with the monkeys.
Swing and Doll got used to life outside the cage, but Koebner had to leave them at some point so that the animals also learned to become independent.
When she came back, Doll and Swing showed that they remembered their savior very well.
They receive her with a touching greeting.
Unlike humans, feelings like gratitude and loyalty are highly developed in animals.
Regards and a good night from Venus