Of course, you can always do it in a zoo. Careful positioning and cropping can yield some excellent pictures. I'll have to dig some out of my archives soon, since it'll be a while before I get a chance to visit the zoo again.
Another way to make things happen is to go for the semi-tame animals in the city or at campgrounds.
... and another squirrel
If you look more closely, you will see that he is chewing on a black walnut. There are little bits of shell dust falling to the ground.
This critter isn't so wild.