I’m not sure what to file this thought under, but I figure I may as well share it. I was holding a couple of my wife’s horses today while our farrier, Chris, shoed them, and we got to talking about horses instincts. I think I was asking about horses hooves in the wild, how they responded to injury or heavy use. He joked that the only reason we really needed to clip their hooves was that we kept them in overly-soft paddocks, fed them high energy feed, and thus they didn’t cover the miles and miles that wild horses would have to in order to get enough to eat. In other words, the ecological niche we created for our horses was so unusual that the whole horse physiology was different.
He also pointed out that most domestic horses, unless they are trained to, will not drink from natural water sources. If they’re accustomed to drinking from troughs or buckets, some will die of thirst before drinking out of a creek or lake. They may recognize that it’s water on some level, but they don’t trust the source unless they’re used to encountering water in this way. Obviously, they might be socialized early in order to become acquainted with water in a wider variety of forms.
I don’t have any information on whether or not a horse has ever died from thirst in the presence of lakes or streams, so I can’t confirm this. (I’ll look it up and report back.) If it is true — and I have no reason to doubt Chris as he’s a deeply knowledgeable guy on the subject of horses — it would be a fascinating case of a very useful ‘instinct’ not being inevitable. It also explains the ‘You can lead a horse to water…’ proverb, which I didn’t really understand until today, in retrospect.