Rats can definitively climb walls, though their capability varies significantly depending on the species and the wall surface. This agility is a central reason rats successfully invade human dwellings, as their climbing prowess allows them to bypass ground-level defenses and access structures from above. Understanding this vertical mobility dictates the strategies a rat uses to find shelter and food.
How High and Which Rats Climb
The two most common pest species, the Roof Rat and the Norway Rat, exhibit distinct abilities regarding vertical movement. The Roof Rat (Rattus rattus) is the true arboreal specialist. It possesses a slender body and a tail longer than its head and body combined, which functions as a superb balancing tool. These rats are excellent climbers, seeking nests in high places like attics and trees, and they easily scale rough vertical surfaces like stucco, brick, and fences to reach the roofline.
The larger Norway Rat (Rattus norvegicus) is primarily a ground-dweller and burrower, often found in basements, sewers, and lower levels of a structure. While they are less agile climbers than Roof Rats, they are capable of vertical ascent. Norway Rats can climb textured surfaces up to several feet. Motivated individuals have been observed to reach heights of two to three meters (about 6.5 to 10 feet) when a food reward is present. Their climbing is slower and more dependent on available footholds compared to the Roof Rat’s movements.
The Mechanics of Rat Climbing
A rat’s climbing success is due to physical adaptations that turn rough surfaces into a navigable landscape. Their feet are equipped with sharp, curved claws that allow them to grip minor imperfections in materials like wood siding, rough concrete, and brick mortar. This claw structure enables them to scale textured exterior walls, relying on friction and small projections to pull their bodies upward.
The rat’s highly flexible skeleton and body structure also play a role in accessing high entry points. They can compress their bodies to fit through gaps as small as a quarter-sized hole; if the skull passes through, the rest of the body follows. A rat can also use its back braced against a wall while its feet push on a vertical pipe, effectively “shimming” its way up drain pipes or utility conduits. Furthermore, their tail maintains balance when navigating thin, horizontal hazards like electrical wires and power lines.
Securing Your Home Against Climbing Rats
Protecting a structure against climbing rodents requires focusing on exclusion points that exploit their vertical pathways. A primary step is trimming back any tree branches, shrubs, or vines within several feet of the roof, gutters, or siding. These plants act as a direct ladder, eliminating a common bridge that allows rats to bypass the lower foundation.
Inspect all utility entry points where pipes, cables, and vents penetrate the exterior walls, especially those leading to the attic. Any gaps larger than a quarter-inch must be sealed using durable materials like galvanized wire mesh or copper wool, as standard caulking or foam is easily gnawed through. For vertical pipes and conduits, installing smooth metal barriers or cones prevents a rat from establishing the necessary grip or leverage to climb higher.