Why are there no green mammals?

The question is:
Why are there no green mammals?

I have been thinking about this question for some time. I have yet to get a satisfactory answer, but some people have brought up some probably useful ideas…

Here’s what I’ve thought of so far, in no particular order.

  1. There are green reptiles, amphibians, insects, spiders, crustaceans, plants, fish, birds and invertebrates. I think that covers most every other form of life on the planet. I’m not a biologist, but I think that list accounts for most things.
  2. For all of those other species, whether the creature is predator or prey, there are plenty of examples of green animals.
  3. But not for mammals. No green mammals.
  4. The question is not moot, and it is relevant. I’m not for example, asking why there are no silver and pink striped mammals. There are many other green creatures…
  5. Mammals share the same habitats as many of these other animals: forests; deserts; grassy plains; jungles; etc. Mammals even share aquatic habitats, part of the time and even much of their lives with these other animals.
  6. From (5) above, if other creatures have found an advantage, through evolution, of being green, why hasn’t a single mammal evolved to the color green?

One person I asked the question of, pointed out that Darwin would have asked whether there was a need for a given mammal to be green. This is a good point and worth thinking about. My initial thoughts are yes, justified by points 5 and 6 above.
I thought that it might have something to do with mammals being so young, relative to some of the other kinds of animals, such as reptiles and fish.
To the people who insist that no mammal could find an advantage from being green, I can only reply with a stunned look. Other species living in the same environment, whether they be predator or prey, find clear advantage from being green (for better camouflage or stealth, for example). Why would a mammal in the same environment not be favored by the same coloring?

I would like to discuss this with anyone interested. I feel there is some big picture here that is being missed.

Thanks in advance,
Ted

Obviously you haven’t been to a shopping mall recently. :D:D

Actually, some sloths are green. But not by their own body. They move so slowly that moss grows on them, and the run-off from it leaches chlorophyll that runs down and stains their hair. I guess it’s somewhat a camoflage scheme, even though I don’t think there are any predetors that could get to them anyway.

It’s not easy being green.

Mammals may share the same habitat, but they don’t share the same predators. Something that’ll eat a lizard won’t necessarily eat a wombat or a rhesus monkey. Could be that those things that prey on mammals tend to be color blind?

A googol search did find a reference to a green possum growing in Australia; it has a mix of black, yellow, white, and gray hairs in its fur which blend together to make a lime green…

It’s also worth noting that there are hardly any birds with green pigmentation: Those which appear green or blue, it’s because of a scattering effect in the feathers, similar to what makes the sky blue. At least, so sayeth Cecil. Presumably, since hair doesn’t have the same sort of structure as feathers, it can’t produce the same effect.

I think green would work against a species, according to Darwin’s law of who looks the tastiest. Variants of red, yellow & black are commonly seen on land animals as warning colors (“eat me and die”), any green land animals would probably have been gobbled up long ago.

In other words, Kermit was right!

The words I mentioned in this thread all deal with melanin and variants thereof. As far as I have found in my studies, there are no melanins that produce green hair or skin. The closest thing to green might be plumbeous, or grayish-blue, though that is more of a slate.

(I can’t comment on green/blue birds: most of the raptors at the Center are shades of reds, browns and blacks, and there is NO CHANCE IN HELL that I am getting near the parrot to examine his plumage [nasty biter].)

AWB, thanks for mentioning the sloth. Add manatees to that short list - ones in the wild often have some sort of mossy-colored growth (likely algae) on their backs.

As in AWB’s example of the sloth’s “hair dye”, the green monkey of Central Africa (originally blamed as the carrier of the simian virus which became AIDS in humans)gets its name from its stained fur.

And then there’s the Grinch…

I think Chronos has a good bit of the answer. Green is (mostly) a structural color in animals, and it may not be easy to have a functional hair with the proper structure.

A couple of other points: Most mammals (except for primates) are colorblind, unlike most birds, reptiles, etc. Therefore, if a mammal species is preyed upon mostly by other mammals, being green won’t do it any good as camouflage. Also bright colors can’t function as social signals, as they do in many other animals. (Mammals generally lack bright colors in general, including blue, yellow, orange, red, etc. - recognizing a few exceptions like the Red Fox, and even that’s not very bright.)

Being brown may be just as good camouflage as being green, especially for an active animal that moves between backgrounds. While many reptiles, amphibians, and insects are green for camouflage, they are mostly slow-moving and probably can avoid appearing against a contrasting background.

There’s a relative of the green monkey in Barbados, the description of which states there’s actually spots of green pigment in the hair. Pictures available here:
http://barbados.org/monkeys.htm
Doesn’t look really green to me.

According to the dictionary, the talapoin:

As with Eohippus’s example, some sources do claim the critter to actually have olive-green or grayish-green fur, but if you dig around for a picture, they don’t look any greener to me than the ones in Barbados:

http://www.cabrillo.cc.ca.us/~crsmith/talapoin.html

The San Diego Zoo has experienced green polar bears, which turned out to be due to algae growing in the hollow shafts of their hairs:

http://www.polarbearsalive.org/facts3.htm

(4th item under “polar bear fur”)

And you weren’t supposed to post this until a few weeks from now …

Yeah, the so-called “Green Monkey” does have a sort of gray-green cast to it, but I’d hardly call it really green.

I believe the only green pigment known in birds is turaciverdin, found only in the Touracos of Africa. Otherwise green is produced by a blue structural color overlaid over a yellow pigment.

When it comes to pigmentation, the green colour is made up of primarily yellow with blue added. It doesn’t take much red pigment the third primary colour, to wipe out any semblance of green. It could be the presence of red in any pigment in mammalian fur or hair that prevents the expression of green. Red is after all comlimentary to green, and red quickly darkens green to grey or black.
This statement is from my experience in colour matching only.
That is the only expertise I can offer here, and I merely present this as possibility for the reason we don’t see green mammals.

Hey, check out the green rabbit!

http://www.ekac.org/gfpbunny.html

why are there no white chocolate M & M’s?

Wow. What a doomed-to-get-eaten little creature. Green bunnies: Chicken McNuggets of the forest.