[Light and scanning electron microscopic observations of the long hair of an orangutan (Pongo pygmaeus) with trisomy 22].

Hair samples of a female orang-utan (Pongo pygmaeus) suffering from Trisomy 22 and three healthy orang-utans had been investigated in regard of their resilience, colour, medulla, cross sectional view, shaft diameter and cuticula structure. There were no characters noticed concerning the orang's hair with Trisomy only. The remarkable sex-specific differences found out in hair shaft diameters have been interpreted as a manifestation of the considerable sexual-dimorphism in orang-utans. The hair samples of all four individuals contain some with an anomaly of the cuticula-structure, which may be seen as an expression of the not species-specific environment in zoos.