I had a possum stealing my rat bait. I do put rat bait in the barn and I try to put it where other critters can't get to it except the rats. I had some bait in a rat bait box. The possum was able to mangle the bait box and get the rat poison out. After some research I found out that there is something in their system so the rat bait doesn't affect them. Originally I couldn't figure out how the rat bait kept disappearing as I put it under a work bench that doesn't have much space between the bottom shelf and the floor. I also put some bait in the rat bait box. I put up a camera. I got pictures of the possum with the rat bait in it's mouth, but unfortunately my computer died. I haven't been able to find the picture yet.