There is little food that the opossum will pass up, although they seem to prefer insects and carrion. They also eat frogs, lizards, venomous snakes, worms, birds, eggs, rats and mice, roaches and other insects, seeds and fruit. Whether rural, residential or in the wilderness, opossums are a benefit to any area they inhabit. The nocturnal opossum is attracted to our neighborhoods by the availability of water, pet food left out at night and overripe, rotting fruit that has fallen from trees. The opossum in turn helps keep our neighborhoods clean and free of unwanted, harmful garden pests and rodents, which do carry diseases.