How to Identify Mice and Rats

Mice

Mice are generally on the smaller end of the size spectrum. They are usually 2 ½ – 4 inches long, depending on breed and age, and their fur is typically a dusty gray or brown. They have furry tails and pointed snouts. The two main types of mice home and business owners encounter are:

• House mice: 2 ½ – 3 ¾ inches long and gray with a cream-colored underbelly and large ears
• Deer mice: 2 ¾ – 4 inches long and brown with white or light-colored undersides and small ears

Rats

Rats are larger than mice, ranging in size from 6-10 inches long (not including their tails). Rats are usually darker in color, from dark brown to black or mixtures of both. Their tails are hairless and scaly and are often just about as long as their bodies, and their snouts are typically more blunt or rounded than those of mice. The two main types of rats to keep an eye out for include:

• Norway rats: Commonly referred to as the “street” or “sewer” rat, these rats can be 7-10 inches long, with bristly brown-and-black fur, light-colored bellies, small eyes and ears, and long tails that don’t quite reach the same length as their bodies.
• Roof rats: Sometimes referred to as the “black” or “ship” rat, these rats can be 6-8 inches long with brown-black fur, light-colored bellies, large eyes and ears, and tails that are longer than their bodies.

Behaviors

Mice and rats usually build nests out of clutter and discarded items, such as paper or cardboard products, scraps of cloth, trash, and insulation. They have the ability to squeeze into small spaces, so they may build their nests in places you might not even think possible. Rodents are omnivorous and will consume most kinds of human food (or even pet food) they can access. However, they will often target food items that contain nuts, seeds, grains, and fruits. These pests are social creatures, living in large colonies and families and giving birth to many young at a time in short periods of time, which has given rise to the adage that “you never have just one rodent.” While this saying may not always be true, it’s highly likely that if rodents are allowed to stay in your home, they will begin reproducing, further exacerbating the problem.

Rodent nests may be found in many out-of-the-way places, like inside walls, in unused rooms, and in basements or crawl spaces. Roof rats are also known to live higher up in attics and eaves. Also, since many rodents are nocturnal or active in the morning or evening, they’ll often forage for food sources during that time, especially since this is the time they’re least likely to be caught.

Rodent Health Risks

Rodents are a danger to more than just your property—they’re also a danger to your health. Rats and mice can carry many diseases that are transmittable to humans through their fur or droppings and urine, such as:

• Hantavirus
• Rat bite fever
• Typhus
• Bubonic plague
• Numerous parasites and worms
• Bacteria-borne illnesses like salmonella

Additionally, rodent fur and waste are known to trigger allergies, and may cause health problems in those who are immunocompromised. To avoid these problems, keep your home as rodent-free as possible.