Odd thing is, in this case, Snopes didn’t just make up a silly story, they told us the OPPOSITE of the truth.
Zebras are never used as horses in movies, but horses are often used as zebras. That’s because real zebras are notoriously difficult to train, even when they’ve been raised in captivity.
So, when you see a “zebra” in an old Tarzan film, it’s likely to be a horse or a donkey with black and white stripes painted on.
And in modern movies or circuses, the “zebra” is likely to be a zedonk or zonkey; that is, a zebra/donkey hybrid that has stripes like a zebra, but is docile like a donkey.