Question: why does horse spook when it can see something in the distance?

Rob Stanley answered on 23 Jun 2016:

It probably thinks it sees a predator, or something else threatening.

It’s ancestors thousands to millions of years ago probably only survived in the wild because they were constantly watching the horizon for threats. Often it’s better to be spooked by something that turns out not to be a predator, than to be overconfident and end up eaten!