Horses are popular animals. Humans used to ride many years on the horses, and we still do, but not as much.
Primarily, most died because of wars. They were used as warhorses a hundred years ago.
Now we care better for them.
Millions of years ago, our horses weren't like we know them now. They were small, around 25 cm in length and looked like small deer. They had 'fingers' and paws.
Later their food sources and habitat got destroyed and changed into a wasteland, by what they weren't hidden and safe anymore. They turned into flee animals and their paws turned into one big one. Finally, a hoof. You can still see a bit of the back finger if you look detailled.
Note: Horses were first striped, like zebra's, and then turned into one/two/three color(s).
In the wildlife, they mostly try to escape from predators. There aren't many in the wild. They mostly live in packs (of horses) to watch on each other.