Depending on where you are at, in the warm months of the year, you may also find squirrels that have 'wolves' on them. These large open sores are actually from botfly larvae buried under the skin of the poor squirrel; they stay with the squirrel for some time and can leave huge open wounds after they abandon the 'nest' (it doesn't seem to hurt the squirrel). While I have since heard that such infected squirrels aren't dangerous to eat, I used to leave those for the woods predators.