It's usually good for a laugh when the AI search feature finds an unrelated image like that. I did not see the horse at all in your image!
This happened to me the other day, searching my Google Photos for pictures I had taken of Kangaroos. The AI thought this chihuahua was a kangaroo. At least there is some resemblance.
It's gotta be the ears! Right?
That's what I think too. Plus a similar color.