As far as I know it's on the one hand because it's more difficult for a predator to Single out a Single animal from the herd to hunt it down because the stripes blend the animals into one another. And studies showed that Tsetse-flyes have difficulties seeing stripes, so zebras get less infected with sleeping sickness.

Researchers found out the stripes confuses the biting flies when they try to land on them. A beautiful "fly swatter" indeed. https://www.ucdavis.edu/curiosity/news/how-zebra-stripes-disrupt-flies-flight-patterns

Great fashion sense.

Scientists found that it confuses flies trying to land on them. They did a test with horses, where some were made to look like zebras, and some not; the flies had a very difficult time landing to bite the ones with stripes. Disorienting to disease carrying pests and to predators.

That is not the question you need to be asking, the question should be, are they white stripes on black or black on white? (do I have to tell you this is a joke?)

They confuse predators (like lions, who are colourblind)

It’s actually something that keeps flies away, something that PLAGUE equines. Especially where zebras live! My horse actually wears a fly sheet with zebras for this reason! …And definitely not because I love dressing my horse up as a zebra or anything… 👀 🐎🔂🦓

They are used to confuse their predators.

I read somewhere that it protects them from mosquitoes

camouflage

Many horses still have remnants of the stripe pattern: grullos, duns, and buckskins. These are colors and not necessarily breed specific, but do contain old genes.

Camouflage, probably. Most African predators prefer to go for the kill rather than try to eat live prey as it runs. Much harder to do if you can't tell the butt from the head, because there's a full herd milling about.

To confuse predators.

Camouflage.

Camo

Grass - camouflage

has to do with how their predators see color. tigers are striped, and colored as they are for similar reasons, but they are the predator.

one reason is so, when they are running from predators, its difficult for the predators to differentiate one zebra from another, making it hard for the predators to single one out! and as others said, it also helps them avoid flies!

Camouflage patterns are the landscape written on the bodies of prey animals due to evolutionary pressure from predators.

Camouflage - when seen from the vantage point of a predator, the stripes merge with grass and the animal becomes almost invisible

Their pray can’t see them. Science stuff in the rods and cones… confusing stuff

Zebras developed stripes as a way to fend off predators. They help them blend into their environment. Also when they run from predators, it’s hard to make out just one, as it just looks like a lump of stripes

Strips in grass equals camo against predators with poor color vision, and are particularly useful in twilit conditions. It's like an eye puzzle to a lion.

It allows pthem to get away from pretators more easily. They are in herds, so the stripes make them all blend together.

That's ironic cause they can't puke.