Sorry the pictures don't do a great job at showing, but I've suddenly got these holes in my yard. About 2 weeks ago I first noticed one or two, here or there. Last week I noticed more. Was out there today and they're friggin everywhere! What in the wide world of sports is digging these things? There's probably 50, maybe 100 or more, in the backyard section of a quarter acre lot. They range from neat and orderly (perfect hole, almost like a creepy, miniature alien artifact), to disheveled and irregular shaped. Half inch to two inches wide, 2 inches to 4 inches deep. Nothing in them or trace evidence of anything relevant that I've been able to tell. In case it's relevant, my dog has gotten 3 possums in the last couple weeks. He doesn't kill them though (and neither do I) - a few hours later and they're gone. Could they be digging these? I'm also overrun with moles or voles or some kind of rodent that tunnels under and makes the ground soft. I've dealt with those many times over the years (without these holes) so I don't think it's that, but wondering if maybe something is going after them so I mention them. Thoughts?