Rat Losing Fur???

I started my own rat colony about 2 weeks ago and hand selected 12 females and 6 males to get it started all from the same source. Everything has been going great and everyone seems to be getting along, but today when I came home from work and did my rounds I noticed one of my favorite females missing hair. Has anyone ever seen this and if so do you know what causes it?

http://i202.photobucket.com/albums/a...s/DSC_0644.jpg

http://i202.photobucket.com/albums/a...s/DSC_0647.jpg

http://i202.photobucket.com/albums/a...s/DSC_0648.jpg

Should I separate her from the rest of the group and is there anything to do for it?

Search her for mites, could be that.

I don't have experience with ringworm, but I don't think it causes a mark like that.

First thing I thought when I saw those pictures was ringworm. I'd get that girl into isolation and likewise not bring any of her previous tub mates into contact with your other rats until you know for sure what you're dealing with. I know ringworm(fungal infection) is quite contagious and is passed by contact.

I have checked her and a good handful of the others and don't see any mites, but I did find some dirt around the follicles of their fur. I just handled her last night and she was fine. What can I treat my colony with as a preventive measure to assure none of them are carrying anything?

Kinda looks like ringworm . That can be treated with medication from a vet. But honestly if it is I would just cull your colony and wash down all tacks with bleach and start over . It's highly contagious and will spread to all your rats and even you. Also if you don't know it's not actually a worm. It's a fungus. Why they call it ringworm I duno lol.
It could be mites. Again if it's mites you may as well start over. They are hard to get rid of and if you buy the stuff to treat your rats great, but you can't feed them to your snakes.
Or could just be an irritation.

I'm thinking ringworm as well.
Quarantine her and the rest of her tubmates. But not together since they're potentially infected.
And change their bedding. Contaminated bedding can also carry ringworm.

Try to limit your contact with the infected and possible infected. You personally can pass ringworm to the healthy ones if you don't be careful. So if you want to keep your colony clean, be sure to wash up before handling the others.

You can take your rat to the vet for a skin scrape to make sure it's ringworm. But if you're sure it's ringworm , I bet you can just ask for some ringworm meds.

Anti-fungal creams will work as well.

Good luck

I don't see any irritation to the skin itself though other than a few little scraps. Could the other rats in the tub do something like this? I looked up ringworm and all the photos I looked at look nothing like this other than the spot is a circular shape. I swear it almost looks like her hair has been chewed off but I know she couldn't have done this to herself. I know they're flexible but not that flexible.

That really does look like ringworm and as above said it is contagious to humans.

I have also read the following at many different websites;

Hair Loss

"There are two main causes of bald spots in rats. The most common is barbering, a behavior where a rat obsessively grooms itself or another rat to the point of nibbling off the hair. The result is bald patches or areas where the hair looks like its had a bad haircut. Usually there is no damage to the skin, but sometimes there can be scabs. The most common areas for self-barbering are the front legs and stomach. The most common areas for barbering another rat are on the head, face, neck, and shoulders. These bald spots are not usually symmetrical. Because this behavior doesn't usually cause any health problems, there is no reason to separate a barber from her roommates, unless you are showing your rats. Another cause of bald spots is fungus
Another type of hair loss is a general thinning of the hair. This can occur in a rat infested with lice or tropical rat mites. Although in these cases the rat usually doesn't self-inflict scabs, constant scratching can cause general hair loss, most commonly on the back. Rex rats may tend to have thinning hair as they grow older or if they are stressed due to disease.

In some other animals, such as dogs and cats, a hormone problem can cause hair thinning, although I haven’t seen this in rats. This type of hair loss is usually seen on the flanks, hindquarters and sometimes the stomach and is usually symmetrical."

I have separated the three that are housed together from the rest of the group. I decided to get up a little earlier this morning to check on them to see if things had worsened through the night. As I was sitting in the room I noticed that the male would grab the females by the back (shoulder area) and forcefully hold them down. It almost seemed like he was biting them? The female without the missing hair wouldn't stand for this and would put up a fight. The female that is missing her hair for whatever reason didn't really fight back but she did make sounds that did not sound as if it were an enjoyable treatment.

I don't plan to "cull" off my entire colony because of this and plan to continue with a topical crème to help stop/prevent ringworm. During my reading last night I read that most rats are carrying ringworm but it doesn't affect them. I also read that for ringworm to affect anyone/anything it must enter the skin through a cut/scratch/break in the skin. My thinking now is that if the male was biting and broke her skin that it could have resulted in her getting ringworm.

It looks like excessive grooming to me as well. Another rat or the same rat just nibbled too much.