Norway Rats

Roof Rat

House Mouse

Norway Rats

Norway Rat: Rattus Norvegicus

With a lifespan of up to one year, the Norway Rat is the most common rat in the United States. It is not as long as the Roof Rat, at 6 to 8 inches in length, but appears larger because it tends to be heavy bodied. Its brown fur is shaggy and the Norway Rat has beady eyes and small ears with a blunt snout. The Norway Rat's tail is shorter than its head and body and its droppings are capsule shaped. The Norway Rat is not very nimble on land, but is an outstanding swimmer.

Norway Rats are excellent tunnelers, typically entering buildings to search for meals through their underground burrows. Meals will usually center around meats, but Norway Rats are omnivorous, and they rely heavily on a source of water. Norway Rats will usually remain out of sight during the daylight hours.

Norway Rats are sexually mature at about 2 months, will breed throughout the year and have 4 to 7 litters with up to 12 young per litter. As with other rodents, Norway Rats often carry serious diseases, so it is best to have a pest control professional deal with them.

Halt Bugology Factoid
Originally called the "Hanover rat" by people wishing to link problems in 18th century England with the House of Hanover, it is not known for certain why the brown rat is named Rattus norvegicus (Norwegian rat) as it did not originate from Norway. (Factoid Source: wikipedia)

Roof Rat

Roof Rat : Rattus Rattus

The Roof Rat has smooth black or brown fur and is rather large (at maturity), measuring from 7 to 10 inches long, with a long tail, pointed snout and large ears and eyes. Roof Rats are nimble climbers and can wriggle through holes and openings as small as 1/2 inch wide.

Creating nests inside and under buildings, and in piles of refuse or old wood, though, as their name suggests, they often are found higher up in structures. Roof Rats are omnivorous, but prefer variety in their diet, seeking out grains, vegetables, fruits and nuts.

The Roof Rat can reproduce at the age of four months and will product 4 to 6 litters per year with up to 8 young per litter. Roof Rats typically live up to one year and often are carriers of serious diseases.

Halt Bugology Factoid
Probably the most easily recognized characteristic that differentiates the roof rat from native rats is the tail. Roof rat tails are hairless, scaly, and longer than the combined length of their head and body, whereas the tails of pack rats are hairy, have less apparent scales and are shorter than their head and body. (Factoid Source: University of Arizona Cooperative Extension)

House Mouse

House Mouse: Mus Musculus

The House Mouse, like other rodents, is a prolific breeder and begins breeding at around the age of two months. They can have litters of 4 to 7 young as regularly as every 40 to 50 days. The House Mouse's preferred diet is cereal grains, but they are omnivorous and will make a meal of anything. They will feed from 15 to 20 times per day.

The House Mouse ranges in size from 3 to four inches long when fully grown, and they are small and sleek with large ears, small eyes and a pointed snout. House Mice can be colored from light brown to gray. Signs that a House Mouse is around are their droppings, which are rod shaped.

The House Mouse is a very curious but cautious creature, an excellent climber and can squeeze through cracks and holes as small as 1/4 inch wide, so they can move through a structure very easily. They prefer nesting in buildings and other structures and will typically establish their territory within 30 feet of food sources. Care should always be taken when dealing with a House Mouse issue because they can be carriers of serious diseases.

Halt Bugology Factoid
There's nothing cute about a House Mouse. They contaminate food-preparation surfaces with their feces, which can contain the bacterium that causes food poisoning (salmonellosis).