Query: Besides Camouflage being a reason for having certain hair colors, what other reasons have been discovered? 
Context: These selective pressures favor certain colors in order to increase survival. Camouflage is thought to be a major selection pressure shaping coloration in mammals, although there is also evidence that sexual selection, communication, and physiological processes may influence the evolution of coloration as well. Camouflage is the most predominant mechanism for color variation, as it aids in the concealment of the organisms from predators or from their prey.