The ability to see colors is something that many people take for granted. But there are many people who go through life thinking their vision is "normal," when in reality they experience their sense of sight through a color vision deficiency. A typical person relies on the color of the fruit to determine its ripeness. Looking at a green banana signals the brain that it is not ripe or ready to be eaten; while looking at a brown banana signals that it is overripe and should be thrown away or used for cooking purposes. What if you couldn't see color and had to rely on commonly overlooked details, like shape or texture, to identify the fruit? Humans are not the only ones who can have color vision deficiencies, as is typical in a variety of animal species. Primate color vision has attracted the interest of researchers because it is highly variable (Osorio, Smith, Vorobyev, & Buchanan-Smith, 2004). Dichromatic vision is the norm for many mammals, excluding humans. As for primates, New World monkeys show polymorphism in color vision as some are dichromatic, while others are trichromatic (Saito et al. 2003). Old World monkeys and the howler monkey, a New World monkey, are trichromats. This is due to genetic duplication different from that of Old World monkeys (Osorio et al.). Brief history of primates and color vision: Records state that the first primates appeared at 80-90 Ma (Jacobs, 2009). The primates living at the time are believed to have been nocturnal. Similar to other eutherian mammals (a mammal indigenous to North America, Europe, Africa, and Asia), primates had dichromatic color vision where their retinas most likely “featured single pigments representative of SWS1 (... half of the article. .....Leonhardt, S.D., Tung, J., Camden, J.B., Leal, M. and Drea, C.M. (2008) Seeing red: behavioral evidence for trichromatic color vision in strepsirrhine primates Behavioral Ecology, 11, 1 -12. Osorio, D., Smith, A.C., Vorobyev, M. and Buchanan-Smith H.M. (2004) Fruit detection and selection of primate visual pigments for color vision, 164, 696-708.Simunovic, M.P. 2010) Color Vision Deficit 24, 747-755.Saito, A., Mikami, A., Hasegawa, T., Koida, K., Terao, K., Koike, S., Onishi, A., Takenaka, O.,Teramoto, M., Mori, Y. (2003) Behavioral evidence of color vision deficits in a protanomaly chimpanzee (Pan troglodytes 44,). Additional websites used as references: http://www .animalcorner.co.uk/wildlife/monkeys/monkey_oldworld.htmlhttp://www.cabrillo.edu/~crsmith/monkeycomparisons.html