poorfarm, we are lucky with no predators like weasels and minks, but we do have lots of feral cats and crazy digging squirrels. The only invasion other than snakes so far has been a squirrel who figured out how to dig in. We did not bury any mesh around it as it should have been to predator proof it, but we have packed in countless bags of cypress mulch making it pretty hard to dig through for all but the most determined. Between the much layers and a dog who thinks it should guard the yard by sticking it's head through the dog door all night, we have been safe. The dog keeps most of the cats and squirrels away and the hawks can't get in, although they have tried.