Food of Squirrels Squirrels mostly eat berries and nuts, but everyone knows that. Here is something that sometimes everyone doesn't know. I live at Northwestern University and go to college there, and we have lots of squirrels. I've seen them eat old food out of trash cans and dumsters. Then I say, "Hey squirrel, what are you doing eating out of that dumster?" and they just look up at me and I run away.