Learn More About AZ Pests: Rodents and Mammals

Need to identify the species of your unwelcome visitor? Learn more about the specific types of nuisance mammals in our rodent and mammal pest library.

Rodent and Mammal Pest Library Menu:

> Field Mice

> House Mice

> Norway Rats

> Pack Rats

> Roof Rats

Field Mice

Physical Characteristics:

Grayish-brown colored with light colored underbellies, tail is longer than the body.
Field mice are very small, and have sharp claws

Behavior:

Field mice dwell in fields (of course), swamps, farms, marsh areas, plains, forest, and old rural homes.
They are scavengers and will eat whatever they can find.
These mice will use their fur coat for camouflage from their predators

Facts:

Field Mice are cousins to the rat.
They are extremely intelligent; they fully assess a situation before going outside for food. Often, their plans do not outsmart their predator; normally they will not live to be 2 years.
Field mice are among that quickest reproducers; females will often be pregnant every month; during this time, only the males go out in search for food.
Baby field mice reach maturity within 3 weeks and start reproducing.

House Mice

House mice… not exactly rodents that anyone likes to share their home with, but unfortunately, they seem to be everywhere. Mice are curious little creatures, if something has changed position or is out of place, they will explore it and adjust their travel routes accordingly. House mice can be identified by their small slender bodies, weighing between 1/2 -1 oz. as an adult. Their ears are large, tail is as long as its body; they are usually dark grey on the back and light on the belly, but can be other colors as well: black, light brownish-grey, and even albino.

They prefer to keep their nests in dark, out-of-the-way areas with lots of nesting bits and pieces to keep comfy. Mice have been sharing our living spaces for over 100 years, but that is not the only thing that they share. Mice are known to share diseases and parasites and these pesky rodents are not easy to get rid of. Did you know that an average adult mouse can squeeze through an opening ¼ inch or larger to enter a building?

Norway Rats

Common Names: House Rat, Wharf Rat, Sewer Rat, Water Rat, Grey Rat, Brown Rat

Physical Characteristics:

Norway rat adults weigh approximately 12-16 oz.
Fur is heavy, thick, and course with colors ranging from reddish brown to grayish brown.
Ears are small, nose is big and rounded, and eyes are small and dark. Tail is shorter than the head and body of the rat; it is scaly and semi-naked.
Has poor eyesight including color-blindness; but has keen sense of smell, touch, taste, and hearing.

Behavior:

Norway rats are social animals; they nest in colonies outside and in underground burrows.
They find shelter in homes, food warehouses, stores, hotels, zoos, sewers, dumps, and farms.
Indoors, Norway rats will nest in lower parts of a building. When there is no room or they become overpopulated; they will occupy areas such as wall voids, attics, and furniture.
Norway rats prefer to eat foods that are high in carbohydrates and proteins. They will also feed on small animals, insects, and birds. In sewers, these rats will feed off American cockroaches.
Nocturnal creatures- most of their activity will take place at dusk and before dawn.
Very shy and are eerie of new surroundings and foods. (bait shy)

Facts:

Norway rats were introduced to the United States in 1775 by European settlers.
They are larger, stronger, more aggressive, and more adaptable to cold weather than any other rat species.
The average female Norway rat has 4-7 litters of pups per year; each litter containing 8-12 babies.
The average wild Norway rat lives 5-12 months and captive (pet) rat lives to be 3 or more years.
Norway rats can swim a 1/2 mile in open waters, travel in sewers, and dive through water plumbing traps.

Pack Rats

Common Names: Wood Rat

Physical Characteristics: Liquid black eyes, fluffy, grayish-brown, Big ears, and long tail; body is 6-9 inches long and its tail 5-9 inches long.

Behavior:

In houses, pack rats are active nocturnally, searching for food and nest material.
A peculiar characteristic is that if they find something they want, they will drop what they are currently carrying, for example a piece of cactus, and they will “trade” it for the new item.
They are particularly fond of twigs, stones, dog poop, and shiny objects, leading to tales of rats swapping jewelry for a stone.
Herbivores: Feed on nuts, seeds, fruit, and foliage

Facts:

- There are approximately 22 species of packrats in the Southwest, including Arizona.
- Nests are often called “middens” and have been discovered clear back to the ice age.
- Packrats will make tapping noises with their feet when they are disturbed.
- Females produce 1-2 litters a year, with 2-6 pups in each litter.

Roof Rats

Phoenix’s warm climate and abundant food sources make it an ideal environment for roof rats, a common rodent pest that can cause serious property damage and health concerns. Roof rats—also known as black or ship rats—are skilled climbers that prefer nesting in attics, roofs, and upper structures. They are nocturnal and known for chewing electrical wiring, insulation, and wood, as well as contaminating food and spreading disease.

Roof rats are smaller than Norway rats and have sleek bodies, large ears, and long tails. Common signs of infestation include spindle-shaped droppings, gnaw marks, nighttime scratching noises, and greasy rub marks along walls and surfaces. In Phoenix, citrus trees and closely spaced vegetation allow roof rats to easily move between trees and buildings.

Effective roof rat control includes thorough property inspections, sealing entry points, removing food sources, trimming vegetation away from structures, and using traps or bait stations placed along travel paths. Preventive measures and regular monitoring are essential, as infestations can be difficult to manage without professional help. Working with an experienced pest control company ensures proper exclusion, treatment, and long-term protection to keep homes rodent-free.