A couple of weeks back I noticed a lump on my guinea pigs backside around his hip area. It was obviously big enough that it was noticeable, it felt hard, and the skin around it was 'crumbly'. When I touched it it never seemed to bother him, but I took note of it and decided to keep an eye on it.
After about another week it started to feel bigger, so I took another look at it. Wondering if maybe there wasn't a tick or something in there. But when I went to look at the lump the entire thing, skin and fur, all lifted right up and reveled another layer of skin. There was nothing to be seen under it. And still, it didn't seem to hurt him.
I took him outside yesterday to eat some clover and when I lifted him up the skin flap came right off. There seems to be new fur growing up in the exposed area, and I've seen nothing strange, his behavior isn't different (no itching, scratching, or biting at himself), and as I said, it doesn't seem to bother him in the slightest.
I've been looking online trying to find anything that resembles what he has, but nothing so far has really matched up. The closest thing I've got is the possibility of mites, but I'm unsure about that.
The area:
The piece that came off:
He lives with a rabbit and I haven't noticed anything wrong with him (checked him over, looked at his skin and felt around), so whatever it is hasn't jumped ship yet, takes its time, or is exclusive to guinea pigs?
Any help would be appreciated.
After about another week it started to feel bigger, so I took another look at it. Wondering if maybe there wasn't a tick or something in there. But when I went to look at the lump the entire thing, skin and fur, all lifted right up and reveled another layer of skin. There was nothing to be seen under it. And still, it didn't seem to hurt him.
I took him outside yesterday to eat some clover and when I lifted him up the skin flap came right off. There seems to be new fur growing up in the exposed area, and I've seen nothing strange, his behavior isn't different (no itching, scratching, or biting at himself), and as I said, it doesn't seem to bother him in the slightest.
I've been looking online trying to find anything that resembles what he has, but nothing so far has really matched up. The closest thing I've got is the possibility of mites, but I'm unsure about that.
The area:

The piece that came off:

He lives with a rabbit and I haven't noticed anything wrong with him (checked him over, looked at his skin and felt around), so whatever it is hasn't jumped ship yet, takes its time, or is exclusive to guinea pigs?
Any help would be appreciated.