In the image is a white horse, while it looks like it had a dramatic fall, it is engaging in a healthy behavior called rolling. I've seen a few horses roll in the northern part of Nigeria where I schooled. I could bet they roll to protect themselves from sunburn and the horse in the image might just be having some natural form of protection from it.
Julius traveled miles with his horse in the Sahir desert. The weather was hot, more than he had ever experienced in two years. The heat had dried up the Oasis, for the few days he survived thirst with the Pouch that held much water.
The temperature rose above normal one fateful day , and he decided to take a rest and he made a camp using a few clothings he had packed. From the distance he noticed Danny, his horse making a dramatic fall and bathing himself in the dust. For a minute it was humorous to him, and thought it was playing in the dust.
Mr Adams laughed when Julius shared the story of his horse's behavior with him.
"No, my friend. It was the horse dust bath ritual" Adams told him. "They coat themselves with dust to act as a natural sunscreen against harsh weather, though sometimes they can be all playful" he added.
Julius was happy to meet Adams, their encounter helped him realize how little he knew about horses. They traveled together and talked along the way about the different reactions of horses.