Mice and rats commonly infest structures as they search for food, water, and shelter. Several kinds of mice and rats are found in the United States, but only three are considered major pests: the house mouse, the Norway rat, and the roof rat. They are called “commensal” rodents because of their close association to humans. Both mice and rats have poor eyesight and rely heavily on their keen senses of smell and touch to navigate the environment. House mice are small, gray, and about 7–10 centimeters long when fully grown, with large ears and long tails. Mice are naturally curious creatures and will readily investigate new items placed in their environment. This behavior makes it easier to catch them in traps.
Rats are not native to the United States. They are an introduced species that has thrived here. Norway rats and roof rats are very similar but have different habits and food preferences. Norway rats are stocky, usually brown in color, and about the size of a kitten when fully grown. They have small ears, small eyes, and a short tail. Roof rats are smaller, more slender, and black with large ears and long tails.
Where They Live & What They Eat
Mice are less dependent on humans for survival than rats. They are just as comfortable in grassy fields and cultivated crops as they are living inside your home. Once they establish a nest, they don’t travel far from it (usually no more than 20 feet). Inside homes, mice can nest in just about any undisturbed area, including wall voids, closets, attics, cabinets, appliances, and furniture. House mice feed on many of the same foods that we do.
Rats typically live in close association with humans. They thrive in large cities and are good at traveling through sewer systems and other underground passageways. In homes, they can nest in a variety of places but usually choose dark, warm areas. They can travel far from their nests (up to 100 feet or more), and they feed on many of the same foods that we do. Norway rats prefer to live in burrows and will readily dig underground nests and tunnels. Roof rats prefer to live up high. Some live their entire lives in trees and never touch the ground. Fine with us!
Pain & Prevention
So, how do you prevent an infestation? Keep mice and rats from coming indoors by sealing all potential entryways. Make sure all vents and screens are in good condition. Seal holes around the foundation of your home, where pipes or A/C lines are. Do not use expanding foam because mice can chew through it. Fill in small holes with fine mesh steel wool, and have large holes professionally sealed with cement or metal casings. Trim bushes and tree limbs away from your house and keep grass cut down. Eliminate clutter outside and inside your home. Store food, bird seed, and pet food in heavy plastic or glass containers, and do not leave uneaten foods sitting out.
These simple measures can go a long way in making sure your home stays rodent-free!