Colour discrimination learning in black-handed tamarin (Saguinus midas niger)
Colour is one cue that monkeys use for perceptual segregation of targets and to identify food resources. For fruit-eating primates such as Saguinus, an accurate colour perception would be advantageous to help find ripe fruits at distance. The colour vision abilities of black-handed tamarins (Saguinus midas niger) were assessed through a discrimination learning paradigm using Munsell colour chips as stimuli. Pairs of chips were chosen from an early experiment with protan and deutan humans. The monkeys (three males and one female) were tested with stimuli of the same hue, but different brightness values, in order to make sure that discriminations were based on colour rather than brightness cues. The results showed that the female, but not the males, presented an above-chance performance for stimuli resembling hue conditions under which tamarins forage (oranges vs greens). Colour vision in S. m. niger is discussed according to the advantages and disadvantages of dichromatism in daily search for food as well as to aspects regarding polymorphism in New World monkeys.
KeywordsColour vision Discrimination learning Munsell colour chips Saguinus midas niger Tamarins
This research was supported by CAPES/DAAD/PROBAL (137/02) and FINATEC. D.M.A.P. was a recipient of a doctoral fellowship from CNPq. We are grateful to A.J. Baptista and F.C. Bicudo for helping run the experiments, and to Dr. R. de Oliveira for animal care and maintenance. We are also in debt to the Zoo of Brasilia for supplying one male tamarin. The research protocol was approved by the Animal Research Ethics Committee from the University of Brasilia.
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