Skunks and Raccoons are digging in the yard and lawn looking for a meal, rather than burying a future meal as the squirrels do. One of their favored meals is that of the grub. Grubs are the larval stage of any one of a number of beetles. The primary one these days is the Japanese beetle larvae which has outpaced our more familiar May or June Beetles. This season we really did not have a prolonged hot dry spell, so most of our lawns were perfectly suited for egg laying, spreading out the potential for damage among many lawns, not just a few well managed lawns. More good news this year is that populations of the beetles were lower for most of us, so fewer eggs were laid to become potential dinner for the skunks and raccoons even though our lawns had great egg laying potential. Another positive is since the beetle populations have not fully recovered from 2012 there are fewer adults to lay eggs and when they do the population of hatched larva are spread out over a much larger area lessening lawn damage and making it harder for the skunk and raccoon to do a lot of damage.
It is pretty easy to tell which of the three are doing damage in your lawn. Squirrels don't dig very deep and or wide, dug just enough to set some seeds and take off again. Skunks dig a hole that is shaped like a top – wide at the opening and pointed at the bottom. The hole itself is about two to three inches across at the top with relatively smooth sides. The Skunk hole is rather neat looking in appearance. Skunks dig a hole, maybe finding a grub or not and then move a bit and dig another hole. The other clue that it may have been skunks is that telltale smell they can leave behind if they were disturbed while foraging.
Raccoons can be much more destructive as they have claws that are great for digging and strong legs that provide additional leverage. If a Raccoon senses that a meal is at hand, they will rip up the lawn in a bit of a backwards motion, using claws and the power of their hind legs to peel back the grass in search of those grubs leaving lots of damage as they go. They will stir and churn the lawn making sure they get ever grub possible.
There are other insects that they will eat like earthworms, soil beetles and other similar creatures so you may see some digging whether or not you have any beetle grubs around. You are more likely to see the skunk and raccoon from dusk to dawn, with the holes mysteriously showing while we sleep.