Why are there no green mammals?

3-Second Blueprint (English)

1. Mammalian hair produces only two pigments—brown-black eumelanin and yellow-red pheomelanin—while green sloth coats come from fur algae.
2. Frogs, chameleons, and birds create green mostly via structural coloration that scatters blue wavelengths through overlying yellow pigment.
3. Because most mammalian predators are dichromats unable to tell red from green, reddish-brown fur already provides effective camouflage.