The Norway rat, roof rat and house mouse are the most persistent rodent populations in need of management.
In Florida, Norway rats are most common along the sea coasts and canals. They thrive particularly in areas where garbage is not properly stored.
Norway rats are burrowers and often dig in rubbish and under buildings or concrete slabs. Burrowing can cause damage by undermining the foundations of buildings, eroding banks of levees, disfiguring landscape plantings, and blocking sewer lines.
This rat is reddish-brown and heavy-set with a blunt muzzle. Its tail is about as long as the combined head and body. Adults weigh 3/4 to 1 pound. Their droppings are 3/4 inches long and capsule-shaped.
Roof rats thrive in attics, roof spaces, palm trees and ornamental shrubbery. They are climbers and prefer to nest off the ground. Roof rats are destructive to citrus groves, since they live in citrus trees and gnaw on the fruit. They can be quite destructive in attics, gnawing on electrical wires and rafters.
House mice normally live outdoors in fields, occasionally migrating into structures. In houses, they live behind walls and in cabinets and furniture.
They prefer to feed on grains but usually nibble at a wide variety of foods. House mice require only 1/10 ounce of food and 1/20 ounce of water daily, but can survive on food alone if it has high moisture.
Droppings of roof rat (1/2", left), Norway rat (3/4", center) and house mouse (1/8", right).