When I was moving to another house, I found this plastic bag on the top of the cabinet of my old house. It looks like someone cut it all with a scissor, but no one have access to my bedroom, and it was not me.
I don't thing it could be rats. That bedroom was very tiny and closed, there's no way for a rat to enter.
The house is very near a university with a little "forest", there are many types of mosquito and little flying animals, but I can't imagine which could do this.
I'm just curious. (and not sure if "zoology" is the correct tag here, but I had to choose one)