Bug Blog

Norway Rats And Mice – How They Differ

Norway rats and mice are the most common rodent pests in the US. They are similar in quite a few ways, but different enough to need different control tools. Let’s take a closer look at these two species and what sets them apart.

Norway rats

The first main difference between these two rodents is their size. Rats are significantly larger than mice at about 18 inches in length, with the tail included. In fact, the difference is so large that baby rats can often be confused for mice. However, you can tell when you are dealing with a baby rat because it has a disproportionately large head when compared to its body.

Norway rats will enter the home looking for food, shelter and warmth. While inside, they will build nests inside the walls, basement or attic, and they will attempt to reach your food supplies. They can reproduce very quickly, and they are surprisingly smart, which is why infestations can be difficult to remove. The main threats posed by Norway rats include dozens of diseases and the damage that they cause to the home.


Mice tend to be much smaller than rats at around 6-8 inches in length when you include the tail in the measurement. However, in terms of behavior, the two species tend to be very similar. Both tend to stick to the dark areas of the home, where they are less likely to be detected, and they are both mostly nocturnal.

How these two species are controlled

Since there is such a big size difference between mice and rats, the tools used to control these rodents differ. For example, mouse traps are too small for rats and vice versa. Poisons may also be affected by this size difference, with rats needing more potent poisons or poisons that are used in higher quantities.

Besides these differences, the two species are controlled using a similar method. Identify the pathways in the home and the locations of the nest, and then lay poisoned bait or traps to get the infestation under control. For both species, traps are used for small infestations, and poisons are used when you are dealing with large populations. It’s also best with both of these rodents if you hire a pro to get the infestation under control.

If you have any questions about mice and Norway rats, or if you have an infestation in your home, contact us today.