So last year, there was this report claiming that Zebras evolved to have stripes to confuse biting insects - Science | AAAS
Are there any other animals who have done so too ? Or are the colorings/stripes on other animals simply to camouflage ?
I would presume that the markings on giraffes wasn’t a evolutionary adaptation for camouflage
I can attest from personal experience that giraffes can besurprisingly hard to see in a sunflecked forest.
On the other hand, I haven’t found zebras hard to pick out even in dim light, so I’ve never been particularly convinced by the camouflage explanation in their case.
I believe the theory about zebra stripes had to do with picking out individuals from the herd or distance-gauging, rather than true camouflage.
Isn’t it the case that most mammal species are more or less color-blind? If so, a black-and-white zeeba in a jungle background might appear very different to them, and perhaps be well camouflaged?
This is the theory that resulted in the development of Dazzle Camouflage, used by some navies during WWI.
It’s not an either/or situation. A zebra’s stripes can be beneficial as both camouflage and to confuse flying insects.
Yes, only apes, Old World monkeys, howler monkeys, and certain female New World monkeys have human-like color vision. The rest are colorblind by human standards, which means reds-yellows-greens all appear similar, but blue is very clearly blue. Fewer animals only see black and white, mostly nocturnal species, cetaceans, and pinnipeds.
Zebras are kind of assholes and also herd animals, they only need to hide so much.
One-two-three-where’s-your-breakfast?
That’s what I have heard too.
A predator, such as a lion, has a hard time distinguishing individuals in the herd to chase after.
Which makes sense. Zebras are grazing animals and move in large herds. I am not sure how camouflage would be useful for them. Hard to miss a few hundred of them roaming in the grass when they are as big as they are. Better to find another strategy, which they did.
Remember, zebras evolved to avoid lions and such which see differently than you or I do. I do not know how much a lion’s vision differs from typical house cat but I know your basic tabby is a bit near sighted and does not have full color vision.
I think the argument is that it’s harder to pick out any one zebra from a whole herd. But there are multiple competing theories on this, so I’m on the fence.
Although any theory should also explain the half-striped quagga.
The quagga turns out to be a sub-species of the Plains Zebra with a varying ‘stripe’ pattern. Perhaps in a herd the individual quaggas were just as difficult to pick out as the more regularly patterned zebras.
Okapi has some stripes, but I can’t speak to the evolutionary drivers.
I don’t think they do the herd thing.
Fun facts …
Baby zebras are brown-striped, the stripes turn black as they mature.
When you see multiple zebras, they often stand shoulder to shoulder; the stripes make it confusing to separate individuals, which means it’s hard to figure out how many animals there are, where one ends and the other begins, etc. Like horses they have almost 360-degree vision. The wildebeests like to hang out with them, as they give early warning about approaching predators.
I recall an article about a shark suit with the same principle, but having contrasting sections made it hard for the shark to integrate the image of a diver as being one single large target.
Sub-species don’t work that way - any particular herd would be *either *normal plains zebra *or *quagga.
Zebras are somewhat camouflaged in vegetation, but it’s not great. However, I can easily believe that in a herd in the open the pattern serves as dazzle coloration to distract predators. Zebras spend most of their time in the open away from cover.
Giraffes feed on trees, so they necessarily live where there is some cover. They live in only small loose herds, and scattered in woodland they can be hard to pick out.
It’s true that big cats and other mammalian predators have poor color vision (they are dicromats, rather than trichromats like us) but they would be able to differentiate the high-contrast black-and-white coloration of a zebra from a background.
Of course, lions, leopards, and leopards are colored to match the background, even though their mammalian prey (except for baboons and other monkeys) have equally bad color vision. So are prey animals like the striped Kuduantelope, in which the stripes do serve to break up its outline.
Okapi are related to giraffe. And interestingly the North American pronghorn antelope more than they are African antelopes. All 3 have different strategies, and pronghorn have white patches which are there to make them more visible to conspecifics.