Not to look at gift horse in the mouth

Question

I understand the meaning of the saying and the context it’s used in.

What I don’t understand is why you would look a horse (or gift horse) in the MOUTH. What is special about its mouth?

In: Other

Answer 1

Teeth. There are teeth that get long. It how to tell how old they are. Looking at a horse’s teeth is one way to tell if its an old horse or a young horse.