Rat Facts, Identification, and Control in New York, New Jersey, and Connecticut
Scientific Order: Rodentia
Genus: Rattus (true rats)
The Black Rat (Rattus Rattus)
The Norwegian Rat (Rattus Norvegicus)
Size: Rats are medium-sized rodents that seldom weigh over a pound.
Color: Generally brown or gray, but they can be black.
Signs of Infestation
Rats leave behind cone-shaped, dark brown droppings wherever they live. Rats also constantly chew on any relatively soft surfaces, such as cardboard, plastic, carpet, or even wood, creating bite marks. If rats chew on sensitive material, they could break or damage it!
Rats build nests out of any soft material they can transport and collect. They'll build these small, dirty nests in dark, cramped nooks and crannies. While accessing these nooks and crannies, the grease on rat's bodies may leave behind smudges on the walls.
Treatment and Prevention
Start by protecting your garbage. Keep cans and dumpsters closed and fastened shut whenever you aren't using them. Take the garbage out to your dumpster every night, and keep it in closed plastic bags. Clean your dumpster around once a month.
Rodents like rats can enter cracks and gaps no larger than a dime. Typically, they find these gaps around frames, baseboard, utility lines, ventilation, and roofing. Look for and seal any draft-producing gaps with caulk.
Behavior and Diet
Rats are opportunistic omnivores. They'll eat whatever they can find wherever they can find it, though they tend to prefer grains, fruits, vegetables, seeds, and nuts. They prefer to rely on large quantities of food they can access easily.
Unlike mice, rats are not natural explorers. Instead, they tend to find and stick to pre-designated routes between their nests and food sources throughout a building. They often wear these routes down or leave behind markings along them over time.
Female rats typically give birth to eight to 10 pups per litter. They can also mate and give birth up to seven times in a single year. Rat gestation period is only 21 days. Like other mammals, rats are born helpless and must be nursed by their mothers.
Rat babies reach full sexual maturity in other around five weeks. Upon reaching maturity, they will immediately seek out other mates. Rats live for up to three years in ideal circumstances, though they'll often die sooner.
Rats instinctively avoid certain tastes and odors. However, no rat repellent has been discovered that eliminates an infestation.
Because rats have poor eyesight, they rely primarily on their sense of smell and taste to discern their surroundings.
Rats transmit a variety of diseases to humans and other animals (bacterial, protozoan and viral), parasites (worms) and ectoparasites (fleas, lice and mites).
NYC Health Rat Information Portal
US Fish and Wildlife Service Rats fact sheet
Illinois Department of Public Health Norway Rats Prevention and Control fact sheet