I was looking at a picture of a giraffe today. It’s fur is broken up in to irregular blocks of orange surrounded by cream.
Normally a broken up coat like that is for camouflage purposes, but that means it is either 1) prey hoping to hide from a predator or 2) a predator that needs to sneak up on prey.
Well, I don’t think much preys on giraffes, unless they’re already sick/dying. And giraffes pretty much eat tree leaves, so no need to sneak up on anything.
Besides which – hey, they’re two stories tall! They’re pretty darn noticable no matter what.
Plus, orange/cream? If anything, they ought to blend with brown/grey trunks and green leaves.
Tall, but kinda thin and spindly, with a too-high centre of gravity. Giraffes are cool, but they’re also the ungainly nerds of the large fauna. I’m sure their camo comes in handy when there are big cats around. The colours seem to work too - the environment is often dry and brown, and in any event, there ain’t too many green mammals around.
You’re making the assumption that markings are for camoflague against the background, but that’s often not the primary impetus. The markings on zebras, for instance, are largely held to to confuse potential predators as to the number of animals in a herd or their ability to distinguish the strong from the weak. While the evolutionary advantage to the group as whole is a wash, it is advantageous to individuals who are not the fastest or strongest. In the case of the giraffe, this might be true as well, or it might be that they serve some other purpose (allowing herd members to distinguish between one another) or indeed it might have no apparent (current) advantage at all in adulthood (though it may provide some protection for juvenile giraffes, who are most at threat from predation), just as freckles haven’t allowed the Irish to conquer the world and take their place as the rightous leaders of mankind.
I thought that giraffe “camo” was not so much to camoflauge it by making it blend into the environment, but by making the outlines of one giraffe fuzzy and hard to make out. So any one individual is less likely to get picked out of the herd. Kind of like zebras’ stripes.
WWI era battleships had similar camouflage. I forget the name for it now. “Dazzle”? In any event, it’s well-known in the animal kingdom, and not all camouflage is designed in an attempt to blend with the surroundings. Some make no attempt to pretend not to be there, but will try to make a lethal strike difficult.
I’ve ofttimes wondered that myself: We have humans with blue, green, and occasionally violet eyes, but they are in the minority, and even then the iris isn’t exactly a prominent feature when viewed in the landscape. Animals always seem to be some shade of red/brown. I reckon a purple cow would be way cool.
There are plenty of blue mammals in the ocean. I can’t think of a mammal that has a signficant amount of green in its coat, but I’m probably missing something obvious. Most mammals, though, and particularly large herd mammals don’t make an extra special effort at concealment; there’s scarcely anything they could do in that regard that a predator couldn’t defeat, so why spend the resources on it. I think the most significant natural predator of squirrels are probably birds of prey; they certainly do very little to conceal themselves naturally and readily adapt to urban environments where natural concealment is minimal.
Concealment is more beneficial for predators, particularly stalking predators which lie in wait, but even they rely more on superior agility and hunting prowess than natural camoflauge.
Although that is interesting enough to have its own thread and there are people better prepared than I to answer that, I will give you the short answer. Blue pigments are “expensive” to produce. Most blue animals (fish and birds) create blue by refraction and not by pigments.
Green mammals: Sloths, but that is algae growing on them
In addition, predators pick a target, which as you say is difficult with crazy markings, and go after it. Markings like the zebra’s make it difficult to hold a fix on a particular animal when the herd starts the rush to get away. Birds’ flocks and erratic flight in a flock, as with pigeons, serves the same purpose.
We do have blue animals. There is ablue roan variety of horse. They are mottled blue and grayish white (or maybe it’s whitish gray). I’ve seen milk cows that are bluish and sometimes almost lavender. Cattle also have lavender eyes sometimes.
Incidently there are also gray roan and red roan horses.
Some sources claim that the talapoin is green. If so, it’s the actual fur color, not algae. You might also argue that “greyish green” isn’t really GREEN, and you want to see a mammal the color of a lime.
Color is just a part of camouflage. A lot of it is shape recognition. Things like strips and spots break up the visual pattern of an animal’s body shape and makes it harder to spot. This the same reason why military camouflage incorporates “splotches” of color.
That’s what I thought when I found that picture linked above. I was just looking at it wrong before, as generally “camouflage” in mammals mean looking like earth or treetrunks. The girrafe camo looks aerial - the dark patches look like clumps of twigs and small branches and the light lines look like sky behind them - as seen from lion’s level across a savanna.
If you think about it, it seems strange that tigers are orange - I mean, they’re obviously trying to blend in, right? But then you see one in its natural habitat and it does blend in. I suspect many animals are like that.
