Alan... skunks.. most definitely skunks.
CaT... Momma had some tomato seedlings in moss pots she was getting ready to plant and the skunks tore up the moss pots to get to the root systems...
As for the cat food, we don't leave it out (because the cats are locked in the basement everynight to avoid them becoming midnight snacks for marauding coyotes)... but we have a blue recycling tub that we put the empty cans in and the skunks make a horrendous noise every time they tip it over to get the cans!