To answer the question, no, there are no apparent nipples on predators. That being said, I don't think they would be as apparent as human's because of their skin. Kind of like elephant nipples, which are really only noticeable on the females.
Of course if you're not a fan of the whole breastfeeding idea, there was another really good and plausible theory, made by a fan from another forum, of them feeding their young similar to birds.
So make of it what you will.