A few years ago I was abroad and teaching a clinic. The host had arranged a clinic dinner for all the participants and auditors on a Saturday night. It was an eclectic group of enthusiastic horse lovers including 2 trainers, 3 competitors, some amateur riders, a bodyworker, and an equine veterinarian.
During dinner one of the participants asked me about a problem she had with a horse that was boarding at her ranch. She said the horse was a chronic biter. She didn’t have much to do with it because it was retired, but every time she tried to halter it, or when feeding, or when it was asked to pick up its feet it would try to bite whoever was near. She wanted to know why I thought it would do this. She added that the owner had told her it had been like this since she bought it. The previous owner had learned to live with it.
I said, “I don’t know why she does it. I’d have to play with her to get a feel of what thoughts and emotions were running around inside her.”
One of the trainers added, “It sounds like a classic case of no respect. It’s treating people like she would another horse that was below her in the pecking order.”
Then the vet said, “Well, in my experience most biting is caused by gut pain due to ulcers.”
A thought crossed my mind. I asked, “Why does it have to be pain from an ulcer?”
The vet replied, “ That’s my experience. I bet if we tested we would find ulcers.”
“Okay. Let’s say you do find ulcers in his gut. What makes it a certainty that the ulcers are the cause of the biting? What if he also had chronic migraines and that was the cause?” I asked.
“Easy,” the vet said. “Treat for the ulcers and see if the biting stops.”
“Okay”, I said. “But what if the migraines ease off at about the same time you treat for ulcers?”
The vet said, “Well we can’t test for migraines in horses.”
“No, you can’t,” I responded. “And you can’t test for ear aches or tinnitus or double vision or dizziness either. Could the biting be caused by one or more of those? Yet, we assume it is probably gut ulcers because we can test for them and treat them. I’m not saying that it is not an unreasonable assumption, but I am saying there is a degree of assumption and guesswork in it.”
“As a trainer and not a veterinarian, I might conclude the biting is the result of an habitual behaviour whose cause is long gone, but the behaviour remains. Based on my experience that would seem a logical diagnosis and one I might try to address as a first step. But what if I am wrong and the cause is an ovarian cyst or it hates the foul irritating smell of humans or because the behaviour has been reinforced along the way or because it has a hip problem or because the hat I wear triggers a fear response?”
The discussion was far more amicable than the impression you may be getting from the post. It was the subject of a long talk about when we are working with horses, what they think, feel, and experience, we are all just guessing. The more experienced we are the more educated are our guesses.
But in the end, we are using our best guesses to help our horses. You should avoid anyone who tells you “I know” with unqualified certainty. They don’t.
BTW, does anyone know if horses can suffer migraines? I can't find any definitive testing. The only information I found is based on observing behaviour that researchers say could be a sign of migraine. But no measure of migraines.
We can only try to guess what is causing this level of aggression.