Identification & Types > Mice & Rats

There are several kinds of rats and mice found around Tennessee. However, the Norway rat, roof rat, and the house mouse are the most common pests found in this area.

Rats and mice spread over 35 diseases throughout the world. Rodent-borne diseases are spread directly to humans via contaminated food and water, bite wounds, and through breathing in germs left by these rodents. These diseases from rodents sometimes spread to humans by means of ticks, mites, and fleas that transmit the infection to humans after feeding on infected rodents.

Rats are also known for causing damage to homes and businesses. They chew on electrical wires creating the possible for fire. Rats can also cause damage homes by chewing on roof shingles, water pipes, and fascia boards.

Mice
	The house mouse is one of the most bothersome rodents in the United States. House mice flourish under a mixture of conditions; they are found inside and around homes and commercial buildings, storage sheds and pastures. They also eat and contaminate food with their urine and droppings, which sometimes transmits salmonellosis, a disease associated with food poisoning.  Read More
Rats
	There are two primary species of rats present in Tennessee.The Norway rat and the roof rat. The Norway rat is both larger and heavier than the roof rat. It has a wider distribution and is usually more common, although the roof rat is less plentiful; the species is becoming more prevalent.  Norway rats build their nests in burrows under buildings, low shrubs or ground cover, wood piles, junkyards, and garbage dumps. The roof rat, on the other hand, is a better climber than the Norway rat and is more likely to build its nest in walls, attics, or trees. Read More

House Mice

The house mouse is one of the most troublesome rodents in Tennessee and the United States. Mice thrive in a mixture of environments; mice are found inside homes, commercial buildings, storage sheds, barns, and fields. Mice also eat and contaminate food with urine and feces, which sometimes transmits salmonellosis, a disease associated with food poisoning. 

Indentification
House mice are small animals with relatively large ears and small black eyes. They weigh about 1/2 ounce and usually are light brownish to gray in color. An adult is about 5 to 7 1/2 inches long.

Droppings, gnaw marks, and tracks indicate areas where mice are active. Mouse nests are made from fine shredded paper or other fibrous material. House mice have a musky odor that identifies their presence. Mice are active mostly at night, but they can be seen sometimes during the day.

Biology
Mice usually prefer to eat cereal/grains; they will sample many different foods. They are brilliant climbers and can run up most perpendicular surfaces. They will run across wire cables or ropes and can jump up to 1 foot from the floor. Mice can squeeze through openings slightly larger than 1/4 inch in size. House mice regularly find their way into dwellings in the fall of the year, especially when temperatures become colder outside.

In a single year, a female may have 6 to 10 litters, 3 mice per litter. Young are born 19 to 21 days after mating, and they reach reproductive maturity in 6 to 10 weeks. The life span of a mouse is typically one year, but varies according to strain and environment.

Control
A key to successful mouse control is the elimination shelter and of food sources. Trapping works well including baiting systems. Removal of mice should be followed by taking steps to restrict them so the problem does not persist.

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Rats

There are two primary species of rats present in Tennessee.The Norway rat and the roof rat. The Norway rat is both larger and heavier than the roof rat. It has a wider distribution and is usually more common, although the roof rat is less plentiful; the species is becoming more prevalent.  Norway rats build their nests in burrows under buildings, low shrubs or ground cover, wood piles, junkyards, and garbage dumps. The roof rat, on the other hand, is a better climber than the Norway rat and is more likely to build its nest in walls, attics, or trees.

Norway rat - is 13-18 1/2 inches total length, with its tail being shorter than its head and body combined. An adult Norway rat weighs about 3/4 to 1-1/4 pounds. It is mostly brown, with a lighter colored stomach. The tail is semi-naked and darker above than below, giving it a two-toned effect.

Roof rat It is mostly black with some gray below, although there are some variations. The tail is also semi-naked, but of one color. Their tail is scaly and naked, and usually longer than the head and body. Its fur is smooth.  The average size is roughly 13-inches in length including the tail. Roof rats are slightly smaller than Norway rats.

Biology
Norway rats and roof rats will eat nearly any type of food.  Norway typically prefer high-quality foods such as meat and fresh grain. Roof rats eat the same diet, will also eat fruits and vegetables. Rats usually require ½ to 1 ounce of water daily when feeding on dry foods, but less when moist food is available.

Habitat:
Norway rats live in close association with people. They burrow to make nests under buildings and other structures, beneath concrete slabs, around ponds, in garbage dumps, and at other locations where suitable food, water, and shelter are present.  These rats can climb, but tend to dwell in the lower floors of buildings.

Roof rats nest within structures in high places, but sometimes in basements, sewers, or under buildings. These rats sometimes nest in high places - such as trees ad vines - but will also burrow under vegetation.

Medical Concerns
Rats are one of the dirtiest animals and a huge threat to public health. Some of the disease associated with rats, include:

DISEASE	DESCRIPTION
Plague	Caused by a bite of a rat flea infected with pathogenic bacterium Yersinia pestis. While there have not been any reports of plague in Berkeley, the potential for an outbreak may increase as the rat population expands.
Salmonellosis	Bacterial “food poisoning” that may be transmitted when rodents defecate or urinate on food, dishes, kitchen counters, floors, and other objects associated with humans thus contaminating food or drink.
Leptospirosis	Caused by the bacterial spirochete, Leptospira spp., which humans may become infected through contact with water or ingestion of food contaminated with urine of infected rats.
Murine Typhus	Also known as flea-borne typhus is caused by Rickettsia typhi and it can be transmitted to rodents or other hosts such as humans when infected fecal material from a flea is scratched into the skin or rubbed into the flea bite or an open sore or wound.

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