Behavioral experiments have demonstrated color vision in many animals and several general trends emerge. Old World primates (great apes, macaque monkeys) have color vision, based upon three different cone types, very similar to most humans. Mammals, that are not primates, have only two cone types and their color vision is dichromatic, e.g. they can discriminate between long and short wavelengths (dogs, cats, horses). One percent of humans are also dichromatic. —- from here more info on the page from different scientists. Color of page makes it hard to read though.