Commensal Rodent Identification

By definition, there are three rodent species in the group commonly referred to as "commensal" rodents: the Norway rat, the roof rat, and the house mouse. Proper identification and a detailed understanding of each specie's habits are critical to effective rodent control.

The graphic at the right (click the picture for a larger image, or click here for a really huge one) illustrates the major visible differences between the three species of commensal rodents.

Appearance

The Norway rat has a stocky body, weighing between 12 and 16 ounces as an adult. Rats slightly heavier than this do occur (people often claim to see -- and boast of -- "rats as big as alley cats"), but they are rare. The body fur is coarse and ranges from reddish to grayish brown with buff - white under parts, but there are many color variations including all-black Norway rats. The nose is blunt; the ears are small, close set, and don't reach the eyes when pulled down. The tail is scaly, semi-naked, and shorter than the head and body combined.

The roof rat is more slender than the Norway rat and has a tail that is longer than the head and body combined. Adults weigh between 5 and 9 ounces. The color of the fur is usually grayish black to a solid black, the belly varies from buff-white to all gray. The snout is pointed, and the ears are large and reach the eyes when pulled down. The tail is long and reaches the snout when pulled over the body.

The house mouse is identified by a small slender body weighing between 1/2 to 1 ounce as an adult. The ears are large, and the tail is semi-naked and is as long as the head and body together. The fur is usually dark gray on the back and light gray on the belly, but many color variations are possible. Albino, black, and mixtures of black and white have been bred in the laboratory. Mice can be distinguished from young rats by the mouse's smaller feet, longer tail, and smaller head.

Behavior

In terms of their habits, mice tend to be very curious animals who will readily investigate any new object in their environment. Rats, on the other hand, tend to be xenophobic, meaning that they avoid new objects.

Both mice and rats prefer grain-based foods, but rats in particular will eat almost anything if necessity dictates. In addition, mice do not need free water (but will readily drink it if it is available), whereas rats need a ready supply of free water in order to survive.


	Commensal Rodent Identification By definition, there are three rodent species in the group commonly referred to as "commensal" rodents: the Norway rat, the roof rat, and the house mouse. Proper identification and a detailed understanding of each specie's habits are critical to effective rodent control. The graphic at the right (click the picture for a larger image, or click here for a really huge one) illustrates the major visible differences between the three species of commensal rodents. Appearance The Norway rat has a stocky body, weighing between 12 and 16 ounces as an adult. Rats slightly heavier than this do occur (people often claim to see -- and boast of -- "rats as big as alley cats"), but they are rare. The body fur is coarse and ranges from reddish to grayish brown with buff - white under parts, but there are many color variations including all-black Norway rats. The nose is blunt; the ears are small, close set, and don't reach the eyes when pulled down. The tail is scaly, semi-naked, and shorter than the head and body combined. The roof rat is more slender than the Norway rat and has a tail that is longer than the head and body combined. Adults weigh between 5 and 9 ounces. The color of the fur is usually grayish black to a solid black, the belly varies from buff-white to all gray. The snout is pointed, and the ears are large and reach the eyes when pulled down. The tail is long and reaches the snout when pulled over the body. The house mouse is identified by a small slender body weighing between 1/2 to 1 ounce as an adult. The ears are large, and the tail is semi-naked and is as long as the head and body together. The fur is usually dark gray on the back and light gray on the belly, but many color variations are possible. Albino, black, and mixtures of black and white have been bred in the laboratory. Mice can be distinguished from young rats by the mouse's smaller feet, longer tail, and smaller head. Behavior In terms of their habits, mice tend to be very curious animals who will readily investigate any new object in their environment. Rats, on the other hand, tend to be xenophobic, meaning that they avoid new objects. Both mice and rats prefer grain-based foods, but rats in particular will eat almost anything if necessity dictates. In addition, mice do not need free water (but will readily drink it if it is available), whereas rats need a ready supply of free water in order to survive.