Rodents Pest Library Entry:

Order= Rodentia

Family= Muridae

Common Pest Species:

House Mouse (Mus musculus)

Brown Rat (Rattus norvegicus) aka Norway Rat

Black Rat (Rattus rattus) aka Roof Rat

Deer Mouse (Peromyscus maniculatus)

Active Times:

Both Rats and Mice are most active during the night and twilight hours when they forage for food.


Rats are usually larger than Mice but differentiate in sizes in comparison to each other. They tend to be very good climbers (Roof Rats) and can swim. Mice are very good at making nests inside a home, while Rats tend to make nests around or under the home.

Rats and Mice both have an aversion to bright lights and generally will stay along baseboards or underneath cabinets when moving out in the open inside your home. Mouse urine is very potent, and the droppings of both Rats and Mice can easily be recognized.

Rats and Mice are both carriers for a multitude of diseases that can be contracted by humans through direct contact such as bites/scratches/food contamination or indirect contact with urine/excrement and bites from fleas/ticks/flies. Many families under the order Rodentia carry bacteria that can be transferred in numerous ways to infect a person. Rats and mice are just the most common culprit due to their broad range and large numbers near human populations.


The average time it takes for a female mouse or rat to give birth is ~20 days with around 4 litters born per year each producing 4-12 of young per litter. The average lifespan for a rat is around ~1 year, and the the average lifespan for a mouse is also about ~1 year in an urban environment.


Many rats or mice are Omnivores, meaning they will eat anything that is edible and that they can get to (Ex. Vegetables, cereals, meats, cheeses, and etc. ). Rodent’s are one of the most opportunistic pests when it comes to what they can and will eat.


Hantavirus Pulmonary Syndrome


Rat-Bite Fever

Plague (Yersinia Pestis)

Lyme Disease


Notes/Research Sources:

Brown Rat (Muridae) is larger than the house mouse although a young rat could easily be mistaken for a house mouse, it is also larger than a Black Rat (Roof Rat).

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