This Horse Houdini Has Mastered The Art Of The Escape
Horses don't always leap to the forefront if you ask people to name intelligent animals. Dolphins, of course. Certain breeds of dog. Crows might even come up before horses. That's because horses are a pack animal, and much of their brainpower lends itself best to "group" behavior. Horses not only know who the leader of their pack is, they can even figure out who the boss is in a group of humans. In other words, horses aren't going to be writing any great works of poetry, as their brains are focused on the practical.
Mariska, the horse in this video, certainly has some practical interests in mind when she displays some amazing lock-picking skills. Specifically, food.