Thanks all for the suggestions and I knew you would all find it amazing. We do have chipmunks but they are very small and couldn't possibly strip this tree and carry off that much fruit. Possibly raccoons but I think our dogs would have gotten them long before they did this much work. The pears weren't ripe and were not falling off tree yet. Squirrels (or something) was picking them and throwing them to ground where we would find them partially eaten or with just a bite out of them but I wasn't worried about that because there were so many. Just two days ago I was showing someone the tree and asking if they knew how to put up pears and wanted any. They said they had never seen a tree so loaded but the pears weren't ripe yet and needed more time. Next day they were all GONE. This is not a small pear tree. It's branches are so big around they look like an old live oak. The tree could easily be over 100 years old because the home is 100 years old but it's the second home that was built on this old plantation. Descendants of the original family said there used to be other pear trees and they would sit on balcony and shoot the pears out of the trees.
I'm tempted to go into woods and look around. If whatever took them, piled them somewhere they shouldn't be too hard to find - it would make a mountain.
Oh well....real mystery. I didn't even get the dehydrator out of the box. I bought it after so many plums went to waste because we ate all we could, gave away gallons, and let the ground get carpeted with them - even fed them to chickens. I don't know how to make preserves so that's why I bought the dehydrator and called my mom to see if she would come when the pears got ready.
They were the hard pears but I have been eating them and though they are hard, if peeled, I found them crisp and tart and very good.
I still can't believe this. These pears were so big and heavy that one pear filled my hand.