What makes a myth stick?

I taught a course in July where I presented a theory about how horses develop a cyclic on/off tissue pattern. The graphic I used was of a horse with the "on" portions one color and the "off" portions another. This looked like bands and I used the word band to describe them... the "on" band, etc. Later as we were working with horses the question came up about the "bands" and this seemed to be a new term that was being used. I put a stop to it, I hope, but it could have been the start of a new myth that horses have "bands of tissue", perhaps even different colors!
In my profession, Rolfing, there are a lot of myths that have propegated over the years. When I talk with someone and one of them comes up I label them a myth. My definition of a myth is something that hasn't been independently verified to exist. It doesn't mean that they don't exist just that they don't have more than one source.
It seems that with animals we "alternative" therapists promote a lot of myths. Of course one could argue that the conventional therapists are also guilty of this, like the myths that they understand everything about the drugs they use.
Another source of myths is the new breed of horse owner, that is not satisfied with their horses being horses but need them to be something mythical. They're not satisfied with the manure, the wood chewing, the rolls in the mud or the impatient neigh as you walk out to feed in the morning. They need to have something akin to a Unicorn that is magical beyond their mundane view of the world. But, I'll challenge, the mundane is actually where the magic is, the "ordinary" magic of the sound of wind in the grass, of geese flying overhead, coyotes howling in the night after eating the neighbor's dog. We don't need to look outside of the phenomenal world to find magic because it already is. And, it doesn't need to be mythical if we just pay attentions to it.