The ability to see colors is something that many people take for granted. But many people go through life thinking their vision is “normal,” when in reality they are experiencing impaired vision because of a color vision deficiency. A typical person relies on the color of the fruit to determine its ripeness. Looking at a green banana signals to the brain that it is unripe and not ready to eat; looking at a brown banana means 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 often overlooked details, like shape or texture, to identify the fruit? Humans are not the only ones who can have color vision disorders, as is typical in various 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 exhibit color vision polymorphism since 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 indicate that the first primates appeared between 80 and 90 Ma (Jacobs, 2009). It is believed that the primates living at this time were 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 unique representative pigments of the SWS1 (...... middle of article ......Leonhardt, SD, Tung, J., Camden, JB, Leal, M., & Drea, CM (2008). Seeing red: behavioral evidence for Trichromatic color vision in strepsirrhine primates, 11. , 1-12.Osorio, D., Smith, A.C., Vorobyev, M. and Buchanan-Smith HM (2004) Fruit detection and selection of primate visual pigments for vision of Colors, 164, 696-708.Simunovic, MP (2010) Color vision deficiency 24, 747-755.Saito, A., Mikami, A., Hasegawa, T., Koida, K., Terao, K., Koike, S., Onishi, A., Takenaka, O., Teramoto, M., Mori, Y. (2003). , 171-176. Additional websites used as references). : http://www.animalcorner.co.uk/wildlife/monkeys/monkey_oldworld.html http://www.cabrillo.edu/~crsmith/monkeycomparisons.html