Where I can find information about the study of animal vision?
Color vision was shown to be dichromatic (sensitivity to two color peaks) by Neitz et al. (1989). For a broader review of color vision of mammals, see Jacobs (1993).

Literature Cited

Jacobs, G.H. 1993. The distribution and nature of colour vision among the mammals. Biological Reviews 68: 413-471.

Neitz, J. et al. 1989. Color vision in the dog. Visual Neuroscience 3: 119-125.