You won't ever see a dog or cat with an ear like this. [Click the picture for a better view] Now, the inside of their ear canal gets to looking like this mess, but on the outside they look pretty much okay. That is, until they scratch it raw. They'd love to stick something down inside their ear and scratch it, but they can't use tools in that fashion (the fashion that your mom told you never to do: "Don't put anything in your ear except your elbow!") Even when a dog or cat is really working the ear over, it just gets scraped and scratched. It never develops these huge crusts like this rabbit did. Of course, it takes the rabbit a heck of a long time to get like this (and rabbits do have a different species of mite). Hard to believe that someone could ignore a problem for weeks and weeks, but sometimes they do. This guy was treated successfully, but I only got a telephone follow-up. I wish had an "after" picture.
Even though they don't produce this type of damage, ear mites do live on the skin outside the ear in dogs and cats. Otherwise, they couldn't be transmitted by casual head-to-head contact. Animals are not going to fish goop out of somebody's ear and put it into their own ear (they might eat it, but that's another story).
Coming soon: the story of the veterinarian who put mites in his own ear to see (hear?) how it feels.
P.S. Note on Willy P.'s comment: This gentleman is a well-known specialist in the care of laboratory animals, including rabbits, so pay attention to what he's saying. He's also my classmate from veterinary school, so I know whether or not to trust the guy.