These tracks are nicely distinctive. The opossum has that thrown-back "thumb." Of all mammals in our backyards, raccoons have prints most like our own, though that long bottom of the paw usually stands out pretty well. Skunk prints are broad and the toes are pudgy and point forward. Porcupine prints, not to be seen in the Southeast and south-central states, are usually messy and indistinct. The better indication for them is the scratch marks left by quills dragging the ground!