Why did my dogs nipples disappear?

I adopted a three month old pup a few months ago, she is spayed and easy to train. I spend a lot of time at home since I am a student but I went away for a couple of weeks to visit my sister. The rest of my was home so she was taken care of. But sometime after I got back I was rubbing her belly when I noticed her nipples were gone.. we have another female about the same age and I thought maybe that one bit them off? They're best friends and get along well.. my puppy is always happy and running around but I was just wondering if anyone knew how that was possible! She has no nipples, except for a small mole-like spot where they used to be.. hmm ok well thanks if I get your respond

Asked by Member 1153453 on Feb 3rd 2013 Tagged dog, dogs, pup, puppy, adopt, nipplesgone, nipplesdisappeared, doggyquestion, curious in Dogs and a Clean Home