Why are there no green mammals? What kind of title is that for a that for a tutorial essay? Quite appropriate according to S-J... So what is the answer? Well basically most animals are nocturnal and therefore don't have colour-vision. Why? As always there is a trade-off between one thing and another. It is better to see something in the dark than nothing at all. It also has something to do with the rods and the cones found in the eyes and the way they are "wired" . (To be continued)

Mammals do have green pigments in them called biloverdin (spelling?) that cause the skin to look green when an individual feels ill. That's what gives humans that green tinge. It doesn't seem to have incooperated itself into hair or fur though...