Behavioural evidence of sex-linked colour vision polymorphism in the squirrel monkey Saimiri ustus.

Squirrel monkeys, like most Neotropical primates, display a sex-linked colour vision polymorphism. Here we assess the colour perception of 8 Saimiri ustus by a behavioural paradigm using Munsell colour chips as discriminating stimuli. A random variation in brightness assured that discriminations were based on colour rather than brightness cues.