rat with cheese on a white backgroundRats are widespread throughout North America, they breed year round and produce around 20 young annually. By nature, rats are nocturnal including domesticated pet rats. The two most common species of rats are the Black Rat and the Norway Rat (Common Rat). Both species are found in all parts of the world. There are several ways to differentiate the two; Black Rats are usually smaller and light in build than Norway Rats, with longer tails compared to their body size. Norway Rats will tend to have smaller ears and eyes.

Common Rat Species

Appearance – Norway rats are gray, brown or black colored. The Norway rat is a fairly large, about 10-18 inches from nose to end of tail. The tail is hairless and is shorter than the body. They usually weigh about 12 oz. Their ears are small, covered with short hairs. Their feces is capsule shaped, and about ¾-1 inch. Norway rats are also known as a common or brown rats.

Biology – Even though they thrive in busy cities, they also do well in dry, treeless areas. Norway rats nest on the ground, but nests have also been found in high places or protected areas, like firewood stacks. Norway rats mainly search for food at dawn and dusk.

Prevention Tips – Keep Norway rats out before an invasion even starts. Keep firewood stored far away from buildings and remove garbage piles. Seal any holes larger than 1/4 inch and get rid of moisture and shelter sources.

Appearance – Black rats are typically 8-11 inches long including their tails. They weigh about 4-12 oz. Black rats come in many different colors, despite their name and their fur is scraggly. Other names for the black rat are roof rat, ship rat and house rat.

Biology – Black rats are generalists and eat almost any food from fruits to invertebrates. They typically prefer higher nesting sites, like roofs and upper floors. These pests adapt quickly to their environments and quickly become a nuisance.

Prevention Tips – To keep black rats and other rodents out, make sure all holes are sealed. Black rats can squeeze through spaces as small as a nickel. Seal any cracks and holes. Make sure you have proper drainage and always install gutters or devices that will carry water flow away from the building.

Rat Diseases

Rats are dirty, unwanted guests that can carry a host of germs and diseases. They can also introduce disease-carrying parasites such as fleas and ticks into your home. Rat bites, scratches and rat urine is responsible for the transmission of many diseases including rat-bite fever, hantavirus, and leptospirosis which is responsible for liver and kidney failure. Knowing that signs of a possible rat infestation is a good first step to proper rat pest control.

Signs of Rat Infestation

1. Droppings – One of the first indicators of a rat presence is their droppings. Rat droppings can be anywhere between a half inch and three quarter inches in size (depending on which species is involved).

2. Urine – Another indicator of rat presence is urine trails or puddles of stains on walls and baseboards that look like “grease.” Rat urine leaves a musty scent, most noticeable in smaller enclosed rooms and when humidity is present.

3. Evidence of Chewing – Just like mice, rats are nibblers who can bite through all but glass, metal and thick plastic. If chew marks are found on snack boxes, pet food bags or other food containers, a rat or mouse infestation is likely.

4. Nesting – Rat nests can often be found in warm, dry areas of the house such as under refrigerators, stoves, and dishwashers. Nesting materials include grass, fabric, furniture, cotton and twigs.