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Pet Rats/Red lump on pet rat's vagina.



My 2 year old female Double Rex/ Patchwork rat has a strange issue which is causing me more than a little concern. Approximately 1 week ago, I noticed that she had a slight swelling near her vaginal opening. With a little research I comforted myself with the thought that this was just her going into heat. Now however she is much more swollen, it appears that her entire vaginal opening is pushed out and there is a small area of bright red towards her rear. It is not bleeding or secreting any fluids which I have noticed when checking her each day. There is also another potentially unrelated blackish bump on her skin halfway between her crotch and leg. I have also not noticed any unusual behavior on her part, she still plays and shows affection as she normally would and is eating and drinking normally. In addition her sister and cage-mate is the same age and breed and showing none of the symptoms that the rat with the swelling is.

Thank you very much for any time and help you can offer.

Hi Christina,
The most likely cause of this lump is a tumor. I have seen this before in a few rats. In one case I removed it and had pathology done, and it was a benign tumor, but it grew back. I decided the only way to remove it completely was to remove the whole vagina with it. This is certainly possible if you have a good vet. If you don't have it removed, it will probably continue to grow until you will have to euthanize her, maybe in a few months.

I have written a booklet called Rat Health Care which is for sale on my website at on the Books page.

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Debbie Ducommun


I can answer any questions about pet rats, but you will probably be able find answers to simple questions more quickly on my website at If you have a life-threatening emergency you can try calling me at 530-899-0605. I am not usually on the computer on the weekend.


I have been "The Rat Lady" since 1985 and am recognized as one of the world's experts on pet rats. I have 3 published books and already answer lots of questions about rats daily.

President of Rat Assistance & Teaching Society

I am a monthly columnist for Pet Business magazine, and my writing has appeared in other magazines. I have 3 published books.

BA in Animal Behavior

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