Description of the process of colour change in the fur of a female White-cheeked Gibbon from the juvenile black coat to the light adult coat, starting at the age of 7V2 ar>d finishing at 8I/2 years. The birth of the first young occurred when the female had attained the age of barely 9 years, and of the second 2*/2 years later. The progress of colour change of the first-born female young from the light infant fur to the dark juvenile fur, starting at the age of 9 months and finishing at the age of IV2 years, is described as well as its gradual growth of independence from the 6th/7th month up to the age of about 2 years.