Here are a few possibilities:
* "Cute as a button": This is a common expression used to describe something very charming and adorable.
* "Cute as a bunny": Another popular phrase, it implies something is exceptionally cute and cuddly, like a baby bunny.
* "Cute as a kitten": Similar to the previous one, this phrase emphasizes the small, playful, and lovable nature of a kitten.
Perhaps the person you heard using "cute as a ear" was simply making a joke or playing with words.
If you provide more context about where you heard this phrase, I might be able to provide a more accurate explanation.