Rats and mice both constantly chew and gnaw on things, creating debris, damage and potentially even starting an electrical fire. These rodents are also full of disease and can easily cause harm to humans in the area. Rodents feed off almost anything, have highly developed senses of taste and smell and multiply quickly. Mice and rats can produce over 400 offspring per year. Rodents also leave their droppings and urine in a home as well as greasy smear marks when they brush up against objects.