Odd nesting behavior?

My girl Storm has been doing something I suspect to be nesting. But, I have no Earthly idea as to why, because there is no way in Hades she could be pregnant. There are no boy rats in the house, and I have never seen a wild rat around here ever. And she wouldn't be the only one. Which she is, I'm pretty sure. Lately she's been pulling aspen up onto the level in the CN, which, btw, is a PITA because it falls out of the bars. She pulls up a bunch of it and then lays in her little pile. Any ideas as to why she would be doing it? Is it just instinct? Because, in the wild, she'd be having litters all the time?

My girls have done this a few times with their eco bedding. They would carry it up to the shelves and lay in it. I think they wanted a fluffier place to lay. Is this the first time she has done this? How are her other behaviors? I think that sometimes our kids do silly things like this to throw us off kilter!

She's been doing it for probably around a week. I thought at first that my mom threw a handful of bedding on the shelf when she medicated them for a weekend, but she kept doing it. Odd girl.

ALL of my female rats and several of my males nest, it's normal behavior.

If you're positive she's not preggo then don't worry about it. I need to post a picture one day of the epic nest a group of my boys made. It was the size of a basketball and very well constructed--I felt bad when I had to throw the mess out.

I'm positive she's not preggo. And she's a normal little ratlet. I do, however, want to see your basketball nest!

Mine nest all the time, and I've got two girls and a neutered boy. Especially with Eco bedding. That stuff ends up everywhere in big 'ol nesting piles. They also cram their cubes chock full of bedding and fleece scraps, so much so that the cube is almost spherical. I have NO idea how they fit in there when they do that.

I think its a personality quirk. Let met try to find a picture of cricket when I had her and she nested..BIG TIME. But she wasn't pregnant. =) My friend gave her some shredded newspaper for bedding while she was baby sitting her..and this is what it came out to. Well, I cant find the stupid picture, but It was great!

Its normal behavior, I believe.

My girls usually stuff some shredded paper into their cubes and double hammocks - I assume to fill in the chinks so that it's warmer inside. I saw someone elsewhere mentioned that one of their rats started nesting when he was sick, but the girl of mine who nests the most (I've occasionally see/hear her carting paper around from one part of the cage to the other) is the healthiest, most robust rat I've ever met. She has her days when she goes all out - I think it might be a hormonal thing.