The house mouse (Mus musculus) is native to Central Asia, and was brought to North America by ships from Europe and other points of origin. The house mouse is a very adaptable animal, which thrives under a variety of conditions. They are found in and around homes, and commercial structures, as well as in open fields and agricultural lands. The house mouse is a nibbler and will sample many foods, but prefers to eat cereals and grains. They consume and contaminate food meant for humans, pets, livestock or other animals. In addition to damaging structures and property they can also transmit pathogens that cause disease, like salmonellosis (a form of food poisoning).
Mice are very small rodents, the adult house mouse is about 5 1/2 to 7 1/2 inches long including the 3 to 4 inch tail. They weight only about 1/2 ounce, and are usually brownish to gray in color. They can fit in a crack of only about a quarter inch. They have large ears and small black eyes. Mice are mostly active at night, but occasionally will be seen during the day. Mouse nests are made from shredded paper or other fibrous material. The house mouse has a distinct musky odor that identifies their presence. Droppings, gnawing marks, and tracks will indicate areas that mice are active. Sanitation will not completely control mice, however poor sanitation will help them thrive in larger numbers. Exclusion is the most successful and permanent form of house mouse control.
Rats are some of the most problematic rodents in the US. They consume and contaminate food, damage structures and property, and transmit parasites and diseases to other animals and humans. Some examples of diseases that can be spread by both rats and mice are salmonellosis (acute food poisoning), Rickettsia Pox, Hantavirus (via droppings), tapeworm, infectious jaundice, and tularemia. It has been reported that rats bite more than fifteen thousand people per year including the both the very young and old. They scamper through your attic and walls, keeping you awake at night, and they often chew their way through drywall and enter the home to contaminate food and leave droppings. They like to chew and gnaw everything and create a fire hazard by chewing on electrical wires.
The Norway Ratsaka brown rat or the sewer rats, they are stocky burrowing rodents that are larger than roof rats. The Norway rat is large and robust, with a blunt muzzle, small ears, and is mostly gray in color. They burrow along building foundations, under rubbish and woodpiles and in moist areas around gardens and fields. When they invade a structure, they generally stay at ground level or the basement. Their nests are usually lined with cloth, shredded paper, or fibrous materials. Norway rats eat a wide variety of foods but prefer to eat cereal grains, meats, fish, nuts and some fruits. When scavenging for food and water, the Norway rat usually does not travel further than 100-150 feet in diameter, seldom do they travel further than 300 feet from their burrow or nest. Norway rats and roof rats do not get along. The Norway rat is larger than a roof rat, and the more dominant of the two species, it will kill a roof rat in a fight. The Norway rat has an average of four to six litters per year and may successfully wean 20 or more offspring per year. Norway rats are found throughout the contiguous United States.
Roof ratsare slightly smaller than the Norway Rats and are sometimes called the black rats. Unlike Norway rats, their tails are longer than their heads and bodies combined. Roof rats are very agile climbers and usually live and nest above ground in shrubs, trees and dense vegetation. Roof rats are sleek, have a pointed muzzle, long ears, and are grey to white in color. When they invade structures, they are most often found in the attics, walls, false ceilings and cabinets. The Roof rat also eats a wide variety of foods, but mostly prefers to eat fruits, nuts, grain products, pet food, berries, insects, slugs and snails. Roof rats also enjoy eating fresh fruit still on the trees. When scavenging for food and water, the roof rat routinely travels to up 300 feet. Roof rats have an excellent sense of balance and use their long tails for balance while traveling along utility lines. They move much faster than the Norway rat and are very agile climbers, which helps them quickly escape predators. The roof rat has about three to five litters each year, having five to eight offspring per litter. The roof rat has a more limited geographical range; they prefer ocean-influenced, warmer climates. Both Norway and Roof rats gain entry to structures by gnawing, climbing, jumping, or swimming through sewers and entering through the toilet or broken drains. The Norway rat is a much better swimmer while the Roof rat is more agile and a better climber. Rats, especially young rats (young rats are often confused with the house mouse), can squeeze through a gap of only 1/2 inch.
The photos and information above were provided by the University of Florida