Common Pest: Rats

True rats are various medium-sized, long-tailed rodents belonging to the genus Rattus. The two common species that have the most impact on humans are the black rat (Rattus Rattus) and the brown rat (Rattus Norvegicus, or Norway Rat). The black rat was thought to have originated in Southeast Asia, transported to the near east and Egypt then spread throughout the Roman Empire (by way of cargo ships carrying spices) and finally making their way to England by the first century. Europeans then carried them (where they now live) across the rest of the world, except Antarctica.

Rats live in a pack (or mischief) which is usually dominated by one member, often a male known as the alpha male. His job is to protect the rat herd from predators, find food and to reproduce. Common species are opportunistic survivors and usually live in close proximity to humans. This class relationship to humans is called commensal. (Ecologically speaking, one benefits and the other does not). Commensalism means sharing of food (a more precise translation is to share the table) in human social interaction. This term describes the use of waste food by secondary animals. Rats can be distinguished from mice by their overall size, relatively large feet, longer and thicker tail, elongated snout and a noticeable arch in their back when they walk or are frightened.

When it comes to habitat, the brown rat is the most successful animal on the planet behind humans. The black rat is largely confined to warmer regions, having been supplanted by brown rats in cooler climates and urban areas. Black rats tend to be arboreal, preferring to nest in trees, attics of buildings, warehouses and residential structures. While the larger, more aggressive brown rat burrows in the ground, lives in sewers and alleyways. Black rats are poor swimmers, brown rats are excellent swimmers and both have moderately poor eyesight. In agricultural areas they inhabit barns, crop fields, cliffs, rocks, trees, riverbanks and can be found near most water resources.

Now let’s discuss the rat’s biology and diet. Rats are mammals that are on average 9 to 13 inches long, with a tail of just about the same length and they weigh approximately one pound. (The brown rat can grow to two pounds). Rats are primarily nocturnal and live about one year in the wild, though they may live up to three years in suitable conditions. Females breed throughout the year, producing from three to six litters of up to 10 pups, which become fertile in fewer than eight weeks. They are generalists in their feeding behavior and as a result have become highly adaptable to most environments. They consume almost anything like fruits, fungi, seeds, leaves, mollusks, fish, birds, ducks, eggs, small animals, insects, farm crops, acorns (nuts), poultry and have a diet high in water content. Rats, like most rodents, have front teeth that grow much like our fingernails. They constantly chew on whatever is available as a method of keeping them filed down. They pose a particular threat to structures because one of their favorite things to gnaw on is wiring. When they reach the inner core they get shocked to death and in most cases become the combustible agent causing fires.

Rats are resilient vectors for the transmittance of a variety of diseases. Pathogens are carried in their bloodstream (or their ectoparasites). Black rats are responsible for the spread of bubonic plague (via the rat flea) along with septicemic and pneumonic plague. Bubonic plague is an infection of the lymphatic system caused by the bite of an infected flea. (Pneumonic plague induces coughing and is highly infectious allowing it to be spread from person to person). The subsequent black death which swept through Europe in the mid-14th century, killing an estimated 75 million people (between 30% and 60% of the population) lead to the Dark Ages. Rats carry trichinosis, Weil’s disease, Hanta virus, Strep, rat bite fever, hemorrhagic fever, typhus, swine fever and foot and mouth disease. Sanitation and pest control are the best management tools for keeping rat populations in check. Rats become aggressive in a competitive environment and can threaten humans. The solution must match the problem. If a large fraction of their population is exterminated, the remaining group will tend to increase their reproductive rates to restore the population to its pre-existing level. You can’t implement a substandard management program and expect desirable results. The professionals at Bugs By Brian will design a control program for a single-family residence, a commercial building, multi-unit housing complexes and governmental districts to help solve community wide issues. Some helpful control measures are:

• Trim shrubbery two feet away from the building.
• Remove brush piles or trim trees over hanging the roof.
• Store garbage in rodent proof containers.
• Remove bird and squirrel feeders, don’t scatter seed on the ground.
• Perform regular maintenance on buildings and caulk any entry point.
• Clean any spilled pet food. Don’t leave water bowls out at night.

In imperial Chinese culture, the rat is the first of 12 animals of the Chinese zodiac. They believe that if a person is born in a year of the rat, they will possess similar characteristics like, creativity, intelligence and quick temper. A person would be prefer a northern orientation, get along well with monkeys, but apparently not too well with horses. Europeans still hold a grudge as a result of what happened in the mid-1300s, as evidenced by the interjection of the term “RATS!” where more vulgar words might apply. The word “rat” is still used to define a person of unscrupulous character and is used as both a noun and a verb in criminal slang for an informant. Rats have long been depicted as villains in movies like Willard, and basically thought of as repulsive in most cultures around the globe.