Q. Dog has pink mole on base of tail
A. This may simply be a wart or skin tag. Dogs can develop these as they get older, just like people do. Keep an eye on it, if it changes color, size, shape, starts to bleed or your dog starts chewing on it, get her seen by your vet so they can do an exam and try to identify the origin of the growth. Otherwise, keep an eye on it, and if there are no changes between now and the next vet visit for her annual exam, mention it to your vet so they can note it in her medical records and keep watch on it too.