Scavengers eat scraps. Often, their entire diet consists of left-overs, but where the original meal came from no one can say. Scavengers also have iron stomachs, and display a complete disregard for the "best by" dates listed on perishables. Chunky milk? Call it cheese. Bruised banana? Don't be a baby. Scavengers somehow always find the secret stash of sweets you keep in the cupboard or around your desk at work. No hiding spot is safe from a true scavenger.
Moochers are a subset of scavengers. They're the people who will eat your fries while you work on your burger. They're the ones who ask, "want to split a dessert?" They get their handouts in bits and pieces. Some moochers are bolder than others, but for the most part, they'll just stare at your food until you offer them some.
Urban foragers are a different breed. These people keep track of the edible plants around their neighborhood and harvest them hunter/gatherer-style. Nuts, roots, berries, fruit, mushrooms – urban foragers can identify which ones are edible, and then eat them. Sometimes they will partake in dumpster diving, searching for perfectly good food that has been thrown out by restaurants and grocery stores. As a country, America wastes about 40 percent of the food it produces. There might be enough for a meal in a dumpster near you, if you're a brave soul.