Rats are opportunistic commensal rodents that thrive by living in close association with humans and utilizing the resources our environments provide. A home offers a perfect storm of opportunity, driven by the fundamental needs for survival: food, water, and shelter. When external conditions are harsh or natural food sources become scarce, a human dwelling becomes an attractive target. Rats exploit structural vulnerabilities to gain access, viewing the interior as a secure, temperature-controlled haven.
The Search for Sustenance
The primary motivation for rats entering a house is the availability of food and water, which is easier to find indoors than in the wild. Rats are not specialized eaters and will consume virtually anything unsecured, including pantry items stored in packaging, pet food left in bowls, and unsecured garbage bins.
Rats possess a sensitive sense of smell, allowing them to locate small amounts of food waste or crumbs within wall voids and under appliances. Water sources are equally attractive, especially in drier environments or when outdoor supplies freeze. They seek out leaky pipes, condensation buildup from air conditioning units, dripping faucets, and pet water dishes.
Seeking Shelter and Security
Once inside, the home offers a stable environment that provides protection from predators and extreme weather fluctuations. The temperature-controlled nature of a building is far more comfortable than the harsh outdoors, particularly during cold weather. They are drawn to quiet, secluded spaces like attics, wall voids, basements, and crawl spaces, which offer ideal conditions for nesting and breeding.
These hidden areas also provide a wealth of readily available materials necessary for building a nest. Rats will shred insulation, cardboard, paper, and fabric to line their nests, creating a warm and secure place for their young. The security of the indoor environment allows them to reproduce with less risk, quickly turning a single intrusion into a persistent infestation. They will gnaw on wood, wires, and insulation to shape or enlarge their nesting sites, causing damage in the process.
Common Structural Entry Points
Rats gain access to homes by exploiting numerous, often tiny, structural gaps and vulnerabilities that homeowners frequently overlook. A rat can squeeze its body through any opening approximately a half-inch to five-eighths of an inch in diameter. This is possible because rats have collapsible skeletons, allowing them to flatten their bodies to navigate tight spaces.
Common entry points include gaps surrounding utility lines and pipes, such as those leading to water heaters or exterior air conditioning units. They frequently enter through damaged ventilation screens, uncapped chimneys, and loose roof eaves or fascia boards. Even the space beneath an exterior door with worn-out weather stripping or a small foundation crack serves as an invitation. Rats are skilled climbers, utilizing trees, vines, and downspouts to reach upper-level entry points like roof vents or attic openings.