Rodents 101

Rodents invade approximately 21 million U.S. homes each winter. While they may be smaller in size, they can pose some really big health risks as well as property threats once inside. Typically seeking shelter and food indoors during the winter months when temperatures drop, rodents are quite adept at invading structures and making themselves at home. From head to tail, their anatomy and physical abilities enable them to squeeze through the smallest of openings and carve out space for themselves to hide once inside.

Rats and mice can spread harmful diseases and cause significant property damage. Females are able to quickly reproduce, allowing undetected infestations to rapidly grow. If you suspect or discover a rodent infestation on your property, contact a licensed pest control professional to evaluate the extent of the problem and execute an appropriate treatment plan. 

About 40 percent of all mammal species on Earth are classified as rodents. However, when it comes to rats and mice in particular, there are four common species that U.S. homeowners need to watch out for. 

Deer Mice: Found throughout the United States, deer mice typically nest in outdoor rural areas such as hollow tree logs, old fence posts and built-up debris. When the climate gets cold, this species may seek shelter in homes, sheds, garages and even unused cars. If they get inside a house, attics and basements provide ideal conditions and they may build nests in places such as wall voids and storage boxes.

Deer mice are the most common carrier of Hantavirus. Primarily transmitted via the inhalation of dust particles contaminated with their urine, feces or saliva, the virus can cause kidney, blood or respiratory ailments, and can also be fatal in some cases.

House Mice: One of the most commonly encountered species, house mice prefer to nest in dark, secluded areas within a structure. Although typically measuring about 2.5 to 3.75 inches in length, they are excellent climbers and can jump up to a foot high. This species can quickly adapt to changing conditions and breeds rapidly, as female house mice can give birth to up to 35 young per year.

If they get inside, house mice can spread diseases such as salmonella and their urine can trigger asthma and allergy symptoms. They can also damage property and are known to gnaw on wiring, sometimes sparking electrical fires.

Norway Rats: Commonly referred to as street or sewer rats, Norway rats can be found throughout the world despite their name. While they aren’t as agile as other species, they have a keen sense of smell, touch and hearing. Primarily nocturnal, they often burrow under concrete slabs or in piles of garbage. Typically, Norway rats will seek shelter indoors when outside food sources become scarce in the fall, typically seeking out basements and other undisturbed household areas.

This species can carry various diseases, contaminate food and introduce pests like fleas into a home. Furthermore, they’re known to chew through almost anything in search of food and water, including plastic and lead pipes.

Roof Rats: Smaller in size compared to Norway rats, this species is most commonly found in coastal states and the southern third of the U.S. Roof rats are social animals that live in colonies and prefer to nest in the upper parts of buildings, such as attics and rafters. Although their lifespan is typically only a year, females can produce as many as 40 new offspring during their lifetime.

Roof rats are historically known for spreading the highly dangerous bubonic plague. While transmission today is rare, there are still a number of cases in the U.S. each year. This species can carry fleas and spread diseases such as jaundice, and is also known to bite in self-defense when threatened. Although rare, being bitten or scratched by a roof rat can transmit rat-bite fever, which can cause nausea, fever and joint pain.

Rodents are potentially dangerous pests that cannot and should not be handled with do-it-yourself remedies. If you suspect or discover an infestation on your property, contact a licensed pest control professional.

For videos, photos and articles about all things rodents, head to the Media section.