Base of rats tail and nose is turning greyish/black

Question
Hi I have 2 albino dumbo rats which are about 5/6 months old. I have recently noticed that 1 of them has developed a greyish/black colouring around the base of her tail and on the top of her nose. She has always been the quieter of the 2 and is less active than the other. Do you have any suggestions as to what this could be and do I need to take her to see a vet?
Any help is appreciated
Lisa

Answer
Hmmmmmm.....can you send a photo?

What your describing is almost a type of rat that is bred called a triamese.(I think I botched that spelling, but I am not a fancy rat breeder so I think I will be forgiven. LOL!)  They also have Siamese rats. They have the extra coloring on the base of the tail and also on their nose.  Often the coloring of the fur darkens as they age.  I wonder if this is what is going on?

A photo would give me some quick answers.  You can attach one photo here after the follow up or if you have several you can send them to my private email at Sandyscrittercity@yahoo.com