Commensal rodents, a term that means “sharing one’s table.” 

These rodents have been coexisting with humans for many years, sharing food and shelter. All rodents have a single pair of extremely strong and sharp teeth that continually grow throughout their life. Rodents keep their teeth sharp by grinding them together or by chewing on objects. Rodents in a house or other structure are a real health problem for at least two reasons. First, when they gnaw on wiring or gas lines to sharpen their teeth, serious or even fatal damage can occur, especially through fire hazards. Second, rodents are notorious vectors of disease. From the fleas they carry, to the trash they walk through, rodents are bad news for human health. Experts estimate that rats and mice destroy enough food every year to feed 200 million people.

Below is a description of the three main commensal rodents: The House Mouse, The Norway Rat and The Roof Rat

House Mouse

With the exception of humans, the House Mouse is the most numerous and widespread mammal on earth. Because of its extremely small size, adaptability, a need for only small amounts of food and water, it is capable of survival in almost any environment. This mouse has a small slender body about ½” to 1” long with large ears and a semi-naked tail that is as long as the head and body together. There are many different colors but it is usually dark gray. The reproductive capacity is incredible and the young can begin making short trips outside the nest in three to four weeks. Mice are curious creatures and explore their territory daily, becoming familiar with pathways and burrow entrances. They are nibblers and may make 20-30 short visits per night to the same feeding spot.

Norway Rat, aka Wharf Rat

This commensal rodent has a stocky body, a stubbier snout, short ears, small eyes and a tail that is shorter than the body and head combined. The hair is coarse and can be reddish, brown or gray. For the most part rats are nocturnal, are not curious, and do not see well. They rely on a complicated sense of direction, memorization of environment and body movements, and a keen sense of smell. They are good swimmers and climbers, too. Norway Rats are extremely well-suited for almost any environment so it’s easy to see they are a formidable foe!

Roof Rat

These rats are smaller and sleeker in stature than the Norway Rat. Roof Rats also have a more pointed snout, larger ears, bigger eyes and a longer tail, which stretches longer than the head and body combined. These rodents prefer a diet of vegetables, fruit, nuts, seeds, and berries. It is very sensitive to changes in its environment and is by nature not very curious. As can be noted by the name, the Roof Rat prefers high places such as, roof lines and will enter buildings on power lines and tree limbs.