Atlantic titi barrier such as a river and are thus completely genetically isolated from one another). Distinctions between each of the "Callicebus" subspecies are based on coat color. The evolution of these coat colors is termed metachromism. The pigments are produced by melanocytes which deposit the pigments into the medulla of growing hair so that the hair grows with the color of that distinct pigment. The characteristic pigment of the "Callicebus" is eumelanin (dark brown or black) found in the iris, skin, and hair (usually on the forehead, crown and tail). Atlantic titis are opportunistic feeders. In other words, they eat based
Pigment chemicals also have their own reflection and absorption patterns, which can affect the final spectrum. For example, in pigment/binder mixtures, individual rays of light may not encounter pigment molecules and may be reflected unchanged. These stray rays of source light make the mixture appear to have a less saturated color. Pure pigment allows very little white light to escape, producing a highly saturated color, while a small quantity of pigment mixed with a lot of white binder will appear unsaturated and pale due to incident white light escaping unchanged. Naturally occurring pigments such as ochres and iron oxides have been