Rats are a familiar pest to many in the United States. Understanding rats’ behavior is key to utilizing proper rodent control, and this includes knowing what kinds of rats you’re dealing with. One of the two species of rats found in the continental U.S., the roof rat is a sleek and agile rodent with its own set of adaptations and preferences apart from its cousin, the Norway rat. Knowing the differences helps with identification and thus prevention or removal, whether done by yourself or with professional Baton Rouge pest control service.
What Is a Roof Rat?
The roof rat (Rattus rattus), also called the black rat or ship rat, was introduced to North America and elsewhere in the world via trading ships. In the United States, it lives along the West Coast and in the southeastern states, unlike the Norway rat’s nationwide range, preferring the warmer climates. Roof rats typically have a mix of brown and black fur with a uniform gray, white or black underside, as well as a slim and slender build compared to the larger Norway rats. They possess the same keen senses of smell, taste, hearing and touch as other rats, as well as an adept sense of balance. Combined with their sleek build, this makes them very capable of climbing and walking across utility lines, tree branches and other narrow pathways to find food and evade predators.
Roof Rat Behavior
True to their name, roof rats like to nest above the ground, settling in trees or atop vine-covered fences and walls. Their natural agility lends itself well to this, as they have little trouble scaling such surfaces. They may be found along streams and riverbeds, within parks that have natural or artificial ponds, or in groves and farmlands - and, of course, within homes and warehouses, entering from the roof and nesting within the upper floors when available while Norway rats prefer the ground floor or basement. Utility lines and trees close to a building’s rooftop are common entry points.
Roof rats are omnivorous and will feed on nearly anything if necessary, but they often have a preference for fruits, nuts and seeds. In homes or on farms, they can develop a taste for livestock feed or dry pet food. The search for food begins early in the evening and may take roof rats as far as 300 feet from the nest to find something to eat. They have no problems gathering heaps of food to eat safely. Roof rats tend to stick to familiar travel routes and feeding locations once identified as safe, so they are not likely to wander into traps laid out traditionally. This is compounded by roof rats’ noted neophobia, or fear and aversion to new objects in their environment, which is stronger in this species than in Norway rats. This means they tend to avoid bait stations and traps, and if sufficiently disturbed, they will change their routes and feeding spots entirely, a behavior that complicates pest control efforts.
Damage and Dangers of Roof Rats
A nest of hungry, omnivorous roof rats presents an obvious concern for homes, food processing and storage facilities, and farms alike. Frequently, roof rats in residential buildings will tear up insulation and electrical wiring as they build nests, particularly in the attic. Wiring damage may also occur in the kitchen when rats hide under the refrigerator or freezer. Gardens and outdoor landscaping may suffer from the foraging of roof rats as they feed on fruits, vegetables, nuts and ornamental plants.
Agricultural orchards are especially endangered by roof rats, which are already inclined to climb trees for food and shelter. They can eat away the pulp from oranges and leave empty rinds hanging and will gladly feast on avocados and nuts as well. Norway rats are more partial to rice and other crops than roof rats, which will prefer the tree crops if present. Roof rats also climb and feed on maturing sugarcane stalks, often leaving them vulnerable to other pests.
Like other rat species, roof rats are carriers for a number of diseases that can be transmitted to humans or domestic animals, as well as potentially carrying parasites. This especially mandates swift rodent control to prevent the spread of such diseases.
Identifying and Controlling Roof Rat Infestations
The specific damage done to outdoor vegetation can help distinguish between a roof or Norway rat infestation. Ruined tree crops are a sure sign of roof rats, in particular. Rat signs, such as tracks, urine and droppings, are not as readily visible with roof rats since they primarily live and travel in overhead and utility spaces rather than along the floor, except when obtaining food.
Visibly confirming the presence of rats naturally works to identify an infestation. Setting a trap to collect rats can help, with the aforementioned caveats regarding roof rats’ aversion to traps. The location of nesting and food caches also helps confirm and distinguish rats, with these found in attics or upper floors mainly for roof rats. Nighttime searches are ideal as rats will be more active at this time and can be heard scurrying about.
To rodent-proof your building against roof rats, the key is to minimize roof level access. When possible, eliminate vines and overhanging tree branches that could permit rats to reach the roof. Given their climbing abilities, this will not completely keep them out alone, and sealing openings greater than 1/2 inch in diameter further ensures exclusion. Use steel wool, concrete mortar or other hard substances that the rats can’t easily chew through.
Proper sanitation can discourage roof rats from moving in; proper disposal of garbage and sealing of food containers makes feeding difficult. Prune outdoor vegetation such as dense shrubbery and vines that roof rats can use to hide or travel.
Baton Rouge pest control services can use rodenticides in bait to control roof rat populations, though they have some resistance to common anticoagulants compared to Norway rats. Trapping is another option, whether using kill traps or live traps, though the tendency to spread disease means releasing trapped rats can cause other problems. Other rodent control methods are of questionable use; fumigants have little effect since roof rats rarely burrow, and deterrent devices using noise or lights are only initially effective until the rats acclimate to them.
I really enjoy researching and writing about pests. The more we know about bugs, the easier it becomes to control them.