Learn More About AZ Pests: Rodents and Mammals

Rodent pest control in Arizona starts with knowing exactly what species you’re dealing with. Use this library to identify the rodents invading your home or property and learn how they behave.

Rodent and Mammal Pest Library Menu:

> Field Mice

> House Mice

> Norway Rats

> Pack Rats

> Roof Rats

Field Mice

Physical Characteristics:

Grayish-brown fur with lighter colored underbellies
Tail is longer than the body
Very small in size with sharp claws suited for digging and climbing

Behavior:

Inhabit a wide range of environments including fields, swamps, farms, marsh areas, plains, forests, and old rural homes
Scavengers that eat whatever they can find — seeds, insects, plant matter, and food scraps
Rely on their grayish-brown fur for camouflage to avoid predators

Facts:

Close relatives of the rat, sharing many of the same survival instincts
Highly intelligent but rarely outsmart their predators — most live less than two years in the wild
Among the fastest reproducers of any rodent — females are often pregnant every month, with only males venturing out for food during this time
Baby field mice reach maturity within three weeks and begin reproducing almost immediately

House Mice

Physical Characteristics:

Small and slender, weighing between 1/2 and 1 oz as an adult
Large ears and a tail roughly as long as the body
Typically dark grey on the back with a lighter belly, though they can also appear black, light brownish-grey, or albino

Behavior:

Curious by nature — if something has changed position or appears out of place, they investigate and adjust their travel routes accordingly
Prefer to nest in dark, out-of-the-way areas with plenty of soft nesting material nearby
Have shared human living spaces for over 100 years

Facts:

Carry diseases and parasites that pose real health risks to people living alongside them
An adult mouse can squeeze through any opening 1/4 inch or larger, making exclusion a critical part of any effective control strategy
Not easy to eliminate once established — professional treatment is typically necessary for complete removal

Norway Rats

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

Physical Characteristics:

Adults weigh approximately 12 to 16 oz
Fur is heavy, thick, and coarse, ranging from reddish brown to grayish brown
Small ears, large rounded nose, and small dark eyes
Tail is shorter than the combined length of the head and body — scaly and semi-naked
Poor eyesight and color-blind, but compensate with a keen sense of smell, touch, taste, and hearing

Behavior:

Social animals that nest in colonies, typically outside in underground burrows
Seek shelter in homes, food warehouses, stores, hotels, zoos, sewers, dumps, and farms
Indoors, they prefer lower parts of a building — when space runs out, they move into wall voids, attics, and furniture
Prefer foods high in carbohydrates and protein but will also eat small animals, insects, birds, and in sewers, American cockroaches
Nocturnal — most active at dusk and just before dawn
Naturally shy and cautious around new surroundings and unfamiliar food, making them notoriously bait-shy

Facts:

European settlers introduced Norway rats to the United States in 1775
Larger, stronger, more aggressive, and better adapted to cold weather than any other rat species
Females produce 4 to 7 litters per year, with each litter containing 8 to 12 pups
Wild Norway rats live 5 to 12 months; captive rats can live 3 or more years
Capable swimmers — can travel 1/2 mile in open water, navigate sewers, and dive through water plumbing traps

Pack Rats

Common Names: Wood Rat

Physical Characteristics:

Liquid black eyes, fluffy grayish-brown fur, and large ears
Body measures 6 to 9 inches in length with a tail ranging from 5 to 9 inches

Behavior:

Nocturnal — spend their nights searching for food and nesting materials
Known for trading behavior — if they find something they want, they drop whatever they are currently carrying and swap it for the new item
Particularly attracted to twigs, stones, and shiny objects, leading to well-known stories of rats swapping jewelry for a stone
Herbivores that feed on nuts, seeds, fruit, and foliage

Facts:

Approximately 22 species of pack rats live in the Southwest, including Arizona
Their nests, called middens, are remarkably durable — researchers have discovered middens dating back to the Ice Age
When disturbed, pack rats tap their feet rapidly as a warning signal
Females produce 1 to 2 litters per year, with 2 to 6 pups in each litter

Roof Rats

Common Names: Black Rat, Ship Rat

Physical Characteristics:

Smaller and more slender than Norway rats
Large ears and a long tail
Sleek body built for climbing and navigating elevated structures

Behavior:

Skilled climbers that prefer nesting in attics, roofs, and upper structures
Nocturnal — active at night and rarely seen during the day
Chew through electrical wiring, insulation, and wood, causing serious structural damage
Contaminate food and spread disease
In Phoenix, they use citrus trees and dense vegetation as pathways between trees and buildings

Facts:

Phoenix’s warm climate and abundant food sources make it one of the most active roof rat environments in Arizona
Common signs of infestation include spindle-shaped droppings, gnaw marks, nighttime scratching sounds in ceilings or walls, and greasy rub marks along travel surfaces
Effective control combines property inspections, sealing entry points, eliminating food sources, trimming vegetation away from structures, and placing traps or bait stations along active travel paths
Infestations grow quickly — professional pest control is the most reliable path to complete, long-term elimination