# Why don't any mammals have green hair? **URL:** \ **Category:** Factual Questions\ **Created:** [April 12, 2003, 3:30pm UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266 "2003-04-12T15:30:05Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![ravenous\_pigeon](https://avatars.discourse-cdn.com/v4/letter/r/f07891/32.png) [@ravenous\_pigeon](https://boards.straightdope.com/u/ravenous_pigeon)\ **Post date:** [April 12, 2003, 3:30pm UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/1 "2003-04-12T15:30:05Z")
Hope this hasn’t been asked before but why don’t any mammals have green hair? I mean, theres plenty of green birds, reptiles, and insects, why not mammals? Surely green hair would be a real advantage as camouflage in the jungle or whatever. Is it something to do with how pigments are used in hair? Anyways, would love to know… ---
**Author:** ![j.c](https://avatars.discourse-cdn.com/v4/letter/j/73ab20/32.png) [@j.c](https://boards.straightdope.com/u/j.c)\ **Post date:** [April 12, 2003, 3:32pm UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/2 "2003-04-12T15:32:41Z")
I assume it has something to do with the pigments available for hair. On the other hand, I’ve seen some sloth and meercats that were slightly greenish. (Really, a light brown and mix of other colors). Still, if you handed a kid a box of crayons, and said, draw this animal, the kid would go for the pea-soup green crayon. ---
**Author:** ![j.c](https://avatars.discourse-cdn.com/v4/letter/j/73ab20/32.png) [@j.c](https://boards.straightdope.com/u/j.c)\ **Post date:** [April 12, 2003, 3:34pm UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/3 "2003-04-12T15:34:40Z")
Oh, and I am talking about bathed sloth in the zoo. Not a wild sloth with algea on its fur. ---
**Author:** ![Laughing\_Lagomorph](https://avatars.discourse-cdn.com/v4/letter/l/6bbea6/32.png) [@Laughing\_Lagomorph](https://boards.straightdope.com/u/Laughing_Lagomorph)\ **Post date:** [April 12, 2003, 3:37pm UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/4 "2003-04-12T15:37:07Z")
I’ve seen quite a few mammals with green hair in places like Harvard Square. But maybe that isn’t what you had in mind… Seriously, I think it is because the range of colors of mammals is just generally more limited than in, say, birds or fish. I can’t off the top of my head think of any non-domesticated mammals with red (really red, not orangey), blue or purple fur either, but there are birds and fish with those colors. I seem to remember that there is a type of sloth that in the wild has algae growing in its fur that gives the animal a greenish color. It helps camoflauge the slow-moving tree dwelling creature. ---
**Author:** ![Laughing\_Lagomorph](https://avatars.discourse-cdn.com/v4/letter/l/6bbea6/32.png) [@Laughing\_Lagomorph](https://boards.straightdope.com/u/Laughing_Lagomorph)\ **Post date:** [April 12, 2003, 3:38pm UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/5 "2003-04-12T15:38:17Z")
Great minds think alike **j.c.**! ---
**Author:** ![CC](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@CC](https://boards.straightdope.com/u/CC)\ **Post date:** [April 12, 2003, 3:52pm UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/6 "2003-04-12T15:52:04Z")
I believe that if green hair had conferred significant advantages to individuals that happend to be born with it, it would have continued and expanded its presence in the gene pool. The fact that it hasn’t happened indicates that its benefits were not sufficient to provide for survival and genetic success. There’s no reason to believe that it couldn’t have developed, but the fact that it didn’t means that other adaptations have sufficed. ---
**Author:** ![Severian](https://avatars.discourse-cdn.com/v4/letter/s/49beb7/32.png) [@Severian](https://boards.straightdope.com/u/Severian)\ **Post date:** [April 12, 2003, 4:03pm UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/7 "2003-04-12T16:03:42Z")
A shot in the dark: Mammals are usually ground-dwellers and, as such, evolution has favored the browns over greens when it comes to camoflage. ---
**Author:** ![Zenster](https://avatars.discourse-cdn.com/v4/letter/z/cdc98d/32.png) [@Zenster](https://boards.straightdope.com/u/Zenster)\ **Post date:** [April 12, 2003, 4:04pm UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/8 "2003-04-12T16:04:58Z")
They were grazed into a chilly extinction by larger ruminants long ago. Actually, many mammals have green hair, you just need to wait for a few weeks after they expire. ---
**Author:** ![vertigo](https://avatars.discourse-cdn.com/v4/letter/v/3ec8ea/32.png) [@vertigo](https://boards.straightdope.com/u/vertigo)\ **Post date:** [April 12, 2003, 4:06pm UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/9 "2003-04-12T16:06:59Z")
Also, aren’t the colors from feathers based on the physical makeup of the feather, as opposed to the actual color? I seem to remember that a blue feather looks blue because of the interaction of light reflecting off of the physical structure of the feather. Whereas a brown hair looks brown because of the absorption properties of the pigment. I’m kinda confusing myself here, so maybe someone who actually knows what there talking about could elaborate if I am getting any of this correctly. So, it’s easier for feathers to reflect more of the spectrum than hair, because of the way pigments show color. It would take a different structure of the hair to mimic what feathers do and that might make the hair not as helpful in insulation or wear, etc. Just a thought. ---
**Author:** ![Horatio\_Hellpop](https://avatars.discourse-cdn.com/v4/letter/h/e5b9ba/32.png) [@Horatio\_Hellpop](https://boards.straightdope.com/u/Horatio_Hellpop)\ **Post date:** [April 12, 2003, 4:46pm UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/10 "2003-04-12T16:46:17Z")
I’ve heard of “green monkeys,” but these are likely brown with kind of an olive tint. The lack of purple mammals was mentioned; Chows (scary bearlike dogs) look rather purplish. > [@](#): > > I seem to remember that a blue feather looks blue because of the interaction of light reflecting off of the physical structure of the feather. Whereas a brown hair looks brown because of the absorption properties of the pigment. Eh. You look at it too closely, there’s no such thing as color, just what we perceive as color. On my primitive level, the perception of color IS color, and isn’t it odd that there aren’t any lime green dogs within my perception range? ---
**Author:** ![Zenster](https://avatars.discourse-cdn.com/v4/letter/z/cdc98d/32.png) [@Zenster](https://boards.straightdope.com/u/Zenster)\ **Post date:** [April 12, 2003, 5:07pm UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/11 "2003-04-12T17:07:23Z")
I refer you to [this](http://www.strangeark.com/biofortean/green.html) site. ---
**Author:** ![everton](https://avatars.discourse-cdn.com/v4/letter/e/ecb155/32.png) [@everton](https://boards.straightdope.com/u/everton)\ **Post date:** [April 12, 2003, 6:46pm UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/12 "2003-04-12T18:46:51Z")
Welcome aboard the SDMB, **ravenous\_pigeon**. This question has been asked before, so you might like to read one of these threads: [Why are there no green mammals?](http://boards.straightdope.com/sdmb/showthread.php?threadid=61562&) [Camoflauge in Mammals- why no green?](http://boards.straightdope.com/sdmb/showthread.php?threadid=47938) ---
**Author:** ![Darwins\_Finch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darwins_finch/32/20304_2.png) [@Darwins\_Finch](https://boards.straightdope.com/u/Darwins_Finch)\ **Post date:** [April 12, 2003, 6:52pm UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/13 "2003-04-12T18:52:23Z")
> [@](#): > > _Originally posted by CC_ > **I believe that if green hair had conferred significant advantages to individuals that happend to be born with it, it would have continued and expanded its presence in the gene pool. The fact that it hasn’t happened indicates that its benefits were not sufficient to provide for survival and genetic success. There’s no reason to believe that it couldn’t have developed, but the fact that it didn’t means that other adaptations have sufficed.** Actually, there is a good reason to believe it couldn’t have evolved: constraint. Simply because a trait might be seen by humans to be adaptive does not necessitate its eventual evolution. In order to evolve, the correct mutation has to first occur before natural selection can take over. If it is physically impossible for the mutation to occur in the first place, then no matter what benefit such a mutation might give an organism, it will never evolve. ---
**Author:** ![CC](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@CC](https://boards.straightdope.com/u/CC)\ **Post date:** [April 12, 2003, 10:00pm UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/14 "2003-04-12T22:00:42Z")
Why would we think it is physically impossible for such a mutation to occur in the first place? ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [April 12, 2003, 11:49pm UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/15 "2003-04-12T23:49:57Z")
> [@](#): > > \*Originally posted by vertigo \* > Also, aren’t the colors from feathers based on the physical makeup of the feather, as opposed to the actual color? I seem to remember that a blue feather looks blue because of the interaction of light reflecting off of the physical structure of the feather. Whereas a brown hair looks brown because of the absorption properties of the pigment. I’m kinda confusing myself here, so maybe someone who actually knows what there talking about could elaborate if I am getting any of this correctly. This guy known as The Cecil sometimes has a clue: [Are blue jays not really blue?](http://www.straightdope.com/columns/000728.html) ---
**Author:** ![Terrifel](https://avatars.discourse-cdn.com/v4/letter/t/c68b51/32.png) [@Terrifel](https://boards.straightdope.com/u/Terrifel)\ **Post date:** [April 13, 2003, 12:38am UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/16 "2003-04-13T00:38:13Z")
Actually, green pigment in birds is not totally unknown; turacos are an African family which produce a vivid copper-based green pigment called turacoverdin. I believe they are unique in this respect; all other birds produce green coloration with the structure of their feathers. Why this should be the case, I dunno. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [April 13, 2003, 1:16am UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/17 "2003-04-13T01:16:13Z")
[Green cat page](http://members.aol.com/messibeast/green-cat/green-genes.htm). ---
**Author:** ![RealityChuck](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/realitychuck/32/195_2.png) [@RealityChuck](https://boards.straightdope.com/u/RealityChuck)\ **Post date:** [April 13, 2003, 2:24am UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/18 "2003-04-13T02:24:13Z")
Back in the late sixties, Newsday published a series of articles about a green puppy, called, appropriately enough, Pistachio. I forget the explanation, but it was certified as being green, though the green color faded as it got older. Also, in some zoos, the polar bears have green hair. This is caused by algae getting inside the hair (which actually has no pigmentation). ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [April 13, 2003, 2:55am UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/19 "2003-04-13T02:55:46Z")
What, you never heard of The Incredible Hulk? The Joker? The Boy with Green Hair? (OK, I know – they are all the result of Unusual Happenings. None of them were born like that.) ---
**Author:** ![Darwins\_Finch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darwins_finch/32/20304_2.png) [@Darwins\_Finch](https://boards.straightdope.com/u/Darwins_Finch)\ **Post date:** [April 13, 2003, 4:11am UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/20 "2003-04-13T04:11:39Z")
> [@](#): > > \*Originally posted by CC \* > \*\*Why would we think it is physically impossible for such a mutation to occur in the first place? \*\* Speaking generally, there are some mutations which are not going to occur, simply because the genome of that organism doesn’t contain the necessary prerequisites (humans aren’t going to be evolving six limbs and gills anytime soon, for example. ). No genome contains the near-infinite “information” that would be necessary to allow for any mutation in every species. This is not to say that the specific mutation of “green hair” is impossible for mammals. My point is that simply because we don’t see something in nature, it is not necessarily the case that it does not exist because it bestows no adaptive usefullness. It may be the case that the proper mutation has just “never come up”, and that, in turn, may be because that mutation is not possible because of a species’ current genome. That we have yet to coax out a “green gene” from any domesticated mammal would seem to indicate that such a gene is not, indeed, lurking in the genome - at least not in any of those domesticated species. [Next page](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266.md?page=2)