The thin animal is a term used by Jungian analysts to refer to the theory that this animal is “porous” and “permeable” and gallops into the Other World of The Dead. The horse has been said to be a thin animal, as Celtic myths were written to narrate how horses have carried their riders and disappeared. Another version of the mysterious power of horses is about when a human takes on the form of a horse and gallops away into an unknown world, never to be seen alive as a human again.
The Celtics, who include the Irish, Scottish Gaelic, Welsh, Breton, Manx and Cornish peoples, have their legends which attributes mysterious powers to the horse. The Germans also have similar fables on humans transforming into horses, or horses being sent to fetch humans who are supposed to pass into The Other World.
This “thin” concept is also used for thin places and watery places, like pools of water of a pond, river, lake, canal, sea and reservoir. The soul supposedly can pass through these thin places. In human logic, it refers to when the human drowns in the watery place, and the soul passes through to the Other World of The Dead.
Related posts on interpreting dreams on horses:
Interpret Dream of Riding Horse.