# 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:** 7\ **Page:** 2
**Author:** ![mnemosyne](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@mnemosyne](https://boards.straightdope.com/u/mnemosyne)\ **Post date:** [April 13, 2003, 4:41am UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/21 "2003-04-13T04:41:30Z")
Most animals don’t tend to rely on colour as an indicator of anything - prey or potential mate. Many animals are partially colourblind, and its been theorized that the ones that aren’t see mostly shades of blue and yellow. Therefore, a green or other outlandish colour is neither an advantage or a disadvantage, and so colours remained whatever they were in the ancestral animal. Adaptations such as spots (cheetahs, for example) arise from a camoflage benfit (hiding in trees, or under them in the dappled sun), as did stripes on animals like zebras. Birds, on the other hand, have bright colours because colour is one trait that HAS been selected for, particularly in mating. Same with insects - both are able to distinguish colours. It has been shown that a female of many species will choose a male with more vivid colours/longer tail feathers/whatever over one that is less visually noticeable. Of course, the provided links and other threads probably have more detail than what my tired mind can explain, so I point you to those… ---
**Author:** ![DocCathode](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/doccathode/32/18773_2.png) [@DocCathode](https://boards.straightdope.com/u/DocCathode)\ **Post date:** [April 13, 2003, 5:24am UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/22 "2003-04-13T05:24:32Z")
> [@](#): > > \*Originally posted by Bryan Ekers \* > \*\*[Green cat page](http://members.aol.com/messibeast/green-cat/green-genes.htm). \*\* It’s the end of Fun Incorporated. It’s the end of the Federal Bureau of Loyalty. It’s the end of the world as we know it! I’m gonna go reread my Fritz Leiber now, to see what else he predicted. ---
**Author:** ![Rusalka](https://avatars.discourse-cdn.com/v4/letter/r/ecd19e/32.png) [@Rusalka](https://boards.straightdope.com/u/Rusalka)\ **Post date:** [April 13, 2003, 6:37am UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/23 "2003-04-13T06:37:48Z")
I hope you all picked up that the page is an April Fool’s Joke (all except the green copper-water drinking kitty at the very top) ---
**Author:** ![DocCathode](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/doccathode/32/18773_2.png) [@DocCathode](https://boards.straightdope.com/u/DocCathode)\ **Post date:** [April 13, 2003, 6:44am UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/24 "2003-04-13T06:44:00Z")
> [@](#): > > \*Originally posted by Rusalka \* > \*\*I hope you all picked up that the page is an April Fool’s Joke (all except the green copper-water drinking kitty at the very top) \*\* Damn! And a green longhair would make such an excellent addition to my Bonsai Kitty collection! ---
**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\ **Post date:** [April 13, 2003, 10:08am UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/25 "2003-04-13T10:08:01Z")
The green skin of some reptiles and amphibians is another structural color, like those of most blue and green birds. Their skin has three different kinds of bodies that together produce the effect. Iridophores have little pigment but they scatter yellow, green and blue light strongly. Xanthophores with yellow pigment absorb the scattered blue and reflect the scattered yellow and green. Melanophores have black pigment and absorb the red and orange that is only weakly scattered by the iridophores. The result is that the skin appears to be green or yellow-green. Mammals have melanosomes that provide the same effect as melanophores in reptiles, but we have nothing like iridophores or xanthophores, so no green. Especially after April 15. ---
**Author:** ![Already\_in\_Use](https://avatars.discourse-cdn.com/v4/letter/a/a9adbd/32.png) [@Already\_in\_Use](https://boards.straightdope.com/u/Already_in_Use)\ **Post date:** [April 13, 2003, 11:23am UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/26 "2003-04-13T11:23:08Z")
There are [a rabbit and some mice](http://abcnews.go.com/sections/science/DailyNews/rabbit000918.html) that fluoresce green under an ultraviolet light. But they’re genetically engineered. ---
**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 13, 2003, 12:54pm UTC](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266/27 "2003-04-13T12:54:31Z")
Dang, didn’t realise this had been asked before. I searched under “green hair” but nothing came up. Anyway, thanks for all the info! [Previous page](https://boards.straightdope.com/t/why-dont-any-mammals-have-green-hair/168266.md?page=1)