ABOVE: The coats of Giant Squirrels Ratufa affinis are very variable between different areas of Borneo. See the illustrations below. However pale morphs occur in low numbers throughout Borneo. It has been speculated that pale morphs are the result of age due to sun bleaching of the fur. This would be easy to prove by examining tooth wear (to estimate age), and comparing teeth and coat colour of different individuals. However this research has yet to be done.
Photo courtesy of Lawrence Chin GM Tabin Wildlife Reserve.