From wiki:
Perception of color is achieved in mammals through color receptors containing pigments with different spectral sensitivities. In most primates closely related to humans there are three types of color receptors (known as cone cells). This confers trichromatic color vision, so these primates, like humans, are known as trichromats.
Many other primates and other mammals are dichromats, only having two colour vision, and many mammals have little or no color vision. Dichromatic vision does occur in humans and is commonly known as colour blindness. So your typical non-primate mammal, probably has a colour receptor range that is an approximation of a colour blind human. Either that or they just see in black and white. Some birds and fish have more colour receptors than humans - up to five and are known as pentachromats. It does foillow, that just because a camo pattern works well on the human eye, doesnt mean it will work well on an animal eye or a birds eye. How well a particular camo works, probably depends on the particular animal you are trying to hide from.
So it follows, that most mamals (not birds) cant see red. For them is just renders as either a shade of khaki green, or a shade of grey, but for us it is a bright, distinct colour.
There are other factors as well, such as how much detail the animals eye can resolve and whether their vision is tuned to shape or movement or both.