Weighing one half to one ounce, the house mouse is grey in color and its body is three to four inches long, with a tail of three to four inches long. The muzzle is pointed, the ears are large, the eyes and body are small.
The female reaches sexual maturity in 35 days and averages eight litters per year, each of which averages six young. House mice typically produce their largest litters in the spring and begin to breed at five to six weeks old. The life span is one year.
The house mouse is a good climber, can jump up to 12 inches high, and can jump down from eight feet. House mice can easily squeeze through holes and gaps wider than ¼-inch. They prefer to nest in dark, secluded areas, where there is little chance of disturbance. Their foraging area is usually small – no more than 20 feet. However, if abundant food is nearby, they nest within four to five feet. House mice nibble on food, preferring items such as seeds and cereals.
The fur of a Norway rat is coarse, shaggy, and brown with some black hairs. The head and body are seven to ten inches long, and the tail is an additional six to eight inches. The muzzle is blunt, eyes and ears are small, and the tail, which is bi-coloured, is shorter than the head and body combined.
Adults are sexually mature within two to five months. Females produce three to six litters per year, each averaging seven to eight young. Adults live from six to twelve months. They have poor site, but keen senses of smell, taste, hearing, and touch.
Rats are nocturnal. Norway rats prefer to nest in burrows in the soil (i.e. under sidewalks and concrete pads, streams/riverbanks, railroad truck beds, next to buildings, in low ground cover, etc). The burrows typically have one main entry hole and at least one escape hole.
They prefer to eat foods such as meat, fish, and cereals and require a separate non-food water source. Their foraging range is 100 to 150 feet from their nest. Rats also cause significant structural and product damage.