We Just Adopted A 1 1/2 Yr. Old Min Pin. The Previous Owners Said She Had Not Been Bred Or Pregnant. Why Does She Have Long Nipples?

I am curious because our other female min pin has tiny, almost flat nipples. When we had her spayed, the vet did not say anything and i forgot to ask. I just wondered if maybe some are bigger than others or if maybe she had puppies.