Insulation, Radiant and Vapor Barriers - Dealing with critters when insulating crawlspace

The mice and chipmunks have the fiberglass bat insulation under the floor all hanging. I know it's animals because I find acorn shells among the fiberglass, and fiberglass in the woodpile outside. Is there a type of insulation that is not attractive to animals? I was thinking of tacking up plastic sheeting from joist to joist and just forgetting the insulation and letting the air gap do the job. Are solid foam boards as attractive to critters?

PS, don't tell me to insulate the foundation walls, because they'd chew that up too!

Didn't you ask this question a few days ago? Same as then, the best answer is to keep them out of the crawl space at all costs. If that isn't possible then you could try rigid foam on the josist but if you do make sure you remove all the old fiberglass insulation first as the foam will keep the insulation from breathing and start trapping moisture in the fiberglass making it useless anyway.

I think in your last post someone stated that the insects like rigid foam so you may have problems with that also.