Rats are history's most notorious disease vectors. Humans noticed the correlation between high rat populations and high incidence of diseases like plague long before scientists understood the basis for the correlation.
In fact, rats were the first animals that were so despised that ordinary people were willing to pay specialists, called "rat catchers," to kill them. Rats are known to be involved in the transmission of serious diseases like bubonic plague, hanta, hemorrhagic fever, rat-bite fever, salmonella, typhus, and probably other diseases.
When they get into homes, rats cause a major health hazard. In addition to the bacterial and arboviral diseases that they help spread, rats also urinate and defecate all over the place, which causes both health hazards and odor problems. Sometimes the contamination can be quite extensive, as this video of a rat-infested attic shows.
In addition to spreading diseases, rats are also very destructive animals. Like all rodents, they have very powerful teeth and jaws that they use to crack the shells on seeds and nuts. They also use those powerful chompers to gnaw their way into homes; and once they get in, they just keep on gnawing. They gnaw on the house itself as well as items stored in the areas that they infest.
Perhaps the worst damage that rats cause occurs when they gnaw on electrical lines, which can cause shorts and fires. They also cause interruptions in telephone, Internet, and cable television service when they gnaw on those wires, as well as failures of doorbells, security cameras and alarms, sound systems, and thermostats for heating and air-conditioning systems.
Rat Species of South Carolina
There are two species of pest rats found in South Carolina. These two species plus the common house mouse comprise a group known as "commensal rodents," meaning that they "eat at the same table" as people. This is another way of saying that they have adapted to living in close proximity to humans and eating our food.
Roof rats (Rattus rattus) are found throughout the state of South Carolina and are the predominant rats in rural and suburban areas. They are sleek, slender, have good balance, and are excellent climbers.
As their name implies, roof rats prefer life in high places. Their habits really aren't very different from those of gray squirrels. In nature, they live in the treetops, using their excellent climbing skills and sense of balance to live high above their predators. In human-populated areas, they prefer the attics and soffits of homes and other buildings, which they often get into by running along tree branches or utility lines.
Norway rats (Rattus norvegicus) are stockier and heavier than roof rats and are ground dwellers. In nature they live in burrows in the soil. In human-populated areas, they are usually found in basements or crawl spaces or on the ground floors of homes and other buildings. They also dig burrows under homes built on slabs, as well as under storage sheds, garages, barns, and other outbuildings. These are also the rats that live in sewers, and yes, they can in fact swim through the sewer and plumbing lines to get into homes.
Although usually found close to the ground, Norway rats can climb quite well when they have a reason to. We do find them in attics and soffits, as well as in the wall voids leading between these areas and the ground. Reasons why Norway rats may climb include overpopulation, cold temperatures, human activity, or predators on the lower floors; or the availability of food on the upper floors.
It's not too unusual to find roof rats in the upper parts of a building and Norway rats in the lower parts of the same building, but it is extremely rare to find them both in the same area of a building. The two species do not get along and cannot interbreed.
Rid-A-Critter completes almost all of our rat control jobs without the use of rodenticides. We control rats by sealing off their entry points and internal travel routes, and then catching and removing the existing rats. Once all the rats are gone, we clean up after them, disinfect and sanitize the area as needed, and usually replace the filthy, contaminated insulation (especially if the infestation was in the attic).
There are many reasons why we don't use rodenticides, but the most basic one is that they're simply unnecessary. Once the home or building is rat-proofed, rats can't get inside anyway; and the existing rats are much more safely and efficiently removed by using traps than by using poisons.
Another problem with rodenticides is that rats who consume them and die inside a home may die in places that are very hard to get to, such as inside wall or ceiling voids. Removing these dead rats can be costly and usually requires cutting into the walls or ceilings. In fact, we get a lot of calls from customers who need dead animal removal because other exterminators decided to treat their rat problems using poisons, and then refused to come back and remove the carcasses.
Finally, rodenticides are toxic to many other animals besides rats. Whenever rat poisons are used, there's always a chance that pets, livestock, or non-target wildlife may be killed. There's also the possibility of secondary poisoning, which occurs when a larger animal or bird of prey eats a rat that has consumed enough of the toxicant to sicken or kill the animal that eats it.
We avoid all of these problems by simply not using rat poisons. If the rat-exclusion job is done properly, poisons are not needed and not worth the risks.
Every rule has its exceptions, including our policy of not using rodenticides. We sometimes do use them in very specific situations.
The first situation in which we use rodenticides is when law or industry policies require them. Many commercial food processing facilities or warehouses, for example, are required to have tamper-proof exterior bait stations that are maintained and checked at every visit. Another example is when a municipality requires a property owner to bait a building for rats before they'll issue a permit to demolish the building. In those sorts of cases we do make exceptions to our policy.
The second situation in which rat poisons are helpful is in wide-area rat control programs, such as control of rats in sewers, where trapping is impractical or impossible. The judicious use of rodenticides in those cases is justified by the health benefits of eliminating rat population over a broad area.
Rat Control Gallery
Here are some pictures we've taken of rats and rat-control throughout our South Carolina regional service area. Please contact us for more information about our long-lasting, exclusion-based rat-removal programs.
Rat hole through a basement wall in Columbia
Norway rat hole into a house in Columbia
Rat gnaw hole in a roof in Lexington
Roof rat entry through gap in the trim in Sumter
Rat hole in the shingles of a house in Greenwood
Norway rat hole in a house in Sumter
Rat smudge marks by cable lines
Roof rat entry hole into a house in Columbia
Rat damage to a crawl space liner
Norway rat entry point into a house in Columbia
Gnaw damage at rat control job in Greenwood
Rats got into a Lexington home through this hole
Rat damage to a soffit vent at a Columbia home
Roof rat hole near the roof of a house in Aiken
Rat entry point into a house in Greenwood
Rats chewed on electrical wires in Aiken, SC
Rat damage to a PVC pipe in an attic
Rat hole in the roof of a house in Columbia
Rat droppings and acorn shells in a crawl space
Rat hole in the attic of a house in Greenwood
Roof rats gnawed a hole into a house in Aiken
Roof rat entry hole into a Lexington home
Roof rat hole in the shingles of a Columbia home
Rat damage to a dishwasher
Technician using fiber-optic scope to find rats
Rat hole in a house in Sumter
Dean getting his game face on for a rat job
Rat hole by the sill plate of a Lexington home