Horses bite for a few reasons, the two main ones though are either play or fear. It’s very important to see the difference when working with a horse so that the behaviour can be dealt with accordingly. While there are very obvious cases out there of horses “attacking” a human, it’s important to note that each and every one of these has many indicators of what was about to happen. Not recognizing it is just poor understanding of the horse by the human to then prevent it from happening. It’s unfortunate but it happens.
This is a video talking about why horses bite and how not all biting is “bad”, even though it should always be discouraged. Having the reputation of owning a horse that bites is undesirable, and in some cases, can have your horse banned from certain places and most definitely from being around children. In the video below I provided every opportunity for the horse to try to bite and only discouraged it at the point that I had enough of the play. The message was understood as you can see by his response. It was a great opportunity to learn and practice.