The lack of green pigments in animals generally suggests there's something metabolically unhappy about them (if you're not planning to photosynthesise)?
It sounds like a cop out, but "just can't do it" might genuinely be the reason. Mammals are just very specialised fish at the end of the day!
Photosynthesis is quite energy-inefficient and requires a huge surface area: animals, for reasons of maintaining structural integrity while moving around, can't provide that. We don't need endosymbiotic chloroplasts when we can just wander around eating ones that can't escape.
Doesn't explain the lack of green pigments in animals altogether though? There are some, but they're pretty rare, and you'd think they'd be useful as either camouflage or for display.
I don’t think green is biochemically affordable as a pigment without using metals, and animals didn’t get custody of chloroplasts when we split off from it plants
I’m also having the vague feeling it’s not reflecting green wavelengths that’s the problem, it’s absorbing the not green wavelengths
"Because mammals only produce two types of pigments in their skin, eumelanin, and pheomelanin. (brown/black and red respectively). All the coat patter[n]s you see in mammals is a linear combination of those two pigments."
From reddit
The only one I can think of that does have a green coat is sloths, that’s actually algae and fungi; their furs structure has evolved to allow trapping of moisture and spores, so over time they go green. Great camo if you live in trees.
Yes I thought of sloths this morning when I woke up wondering about this. I had one on the back of my chair in a restaurant in Quito once, they make a terrifying noise.
My mum once had a green - originally white - Jack Russell terrier. It rolled spectacularly in very fresh cow pats, and it took weeks for the hint-of-poo colour to go.
Okay I'll be THAT person. The colour is to camouflage from the most likely prey/predator. It depends on their eyes. E.g. a bright orange Tiger is invisible to its prey in the grass.
I have read that the prime pray of Tigers do not see orange in the same way we do, meaning that Tigers look green to them. But i have no idea if this is true at all.
Excellent question, by strange coincidence I was listening to an audiobook that mentioned this and suggested green and brown look the same if you only have 2 colour receptors. Presumably brown is an easier pigment to produce.
Odd factoid: I went through RAF training with a cadet who was red-green colour blind. Obviously it restricted his employment (not pilot for example) but normal DPM camouflage just didn't work against him. Brown and green looked the same so the pattern didn't break up outlines.
Would it be great camo though?Grass and foliage are green, but a lot of backgrounds, especially in cover, will be brown. Struck that a lot of modern camouflage clothing for militaries and also civilian hunting/birdwatching etc is browner rather than greener.
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For whatever reason the way fur grows doesn't lend itself to creating the sort of microstructure necessary for iridescence. Hence no green mammals.
It sounds like a cop out, but "just can't do it" might genuinely be the reason. Mammals are just very specialised fish at the end of the day!
I’m also having the vague feeling it’s not reflecting green wavelengths that’s the problem, it’s absorbing the not green wavelengths
From reddit
I believe Humans are more atuned to greens but a quick search suggests this could be a very complifcated subject to read up so I'll park it for now 😵
There is a very interesting relationship between sloths and moths feeding off algae in the fur.
https://royalsociety.org/news/2014/sloths-moths-mutualisms/
Extend that to big cats and it's excellent nocturnal camo