Certain species of rats burrow in the ground as a primary survival mechanism for their colonies. This behavior allows them to establish a secure, subterranean network for nesting and regulating body temperature. Identifying this specific behavior is often the first step in recognizing a rat presence on a property.
Which Rats Burrow and Why
The two most common rat species found near human habitation exhibit distinct nesting preferences. The Norway rat (Rattus norvegicus), also known as the brown or sewer rat, is the species responsible for nearly all ground burrowing activity. In contrast, the Roof rat (Rattus rattus) is an agile climber that prefers elevated nesting sites in attics, rafters, and trees. The Norway rat’s stocky build makes it suited for its terrestrial lifestyle.
Burrowing provides these rodents with a complex shelter that protects them from predators and harsh weather conditions. The tunnel systems typically extend 12 to 18 inches deep, though they can reach depths of up to four feet when dug against a building foundation. Within this network, the rats establish distinct chambers for nesting, raising their young, and storing food caches. A single burrow often features one main entry and several smaller “bolt holes” that function as emergency escape routes.
How to Spot an Active Rat Burrow
The entrance to a Norway rat burrow appears as a round hole with a typical diameter between two and four inches. Active burrows have smooth, compacted edges due to the constant friction of the rat’s body passing in and out of the opening. Freshly excavated soil, often fanned out near the entrance, indicates recent digging or expansion of the tunnel system.
Rats repeatedly use the same travel paths, wearing down vegetation to create runways leading to and from the burrow. Dark, capsule-shaped droppings, measuring approximately one-half to three-quarters of an inch in length, may be found scattered along these runways or adjacent to the hole. Look for burrows located near vertical structures, such as building foundations, retaining walls, or under dense ground cover, as these sites offer structural support and concealment.
Environmental Factors Attracting Burrowing
Rats strategically choose locations based on the proximity of three resources: food, water, and harborage. Accessible food sources are a primary attractant, including improperly stored garbage, unsecured pet food left outdoors, birdseed spilled beneath feeders, and exposed compost piles.
Water draws rats to areas with leaky outdoor faucets, dripping air conditioning units, or standing water in clogged gutters or containers. Once food and water are secured, rats seek out protective harborage, which is dense material offering concealment and cover for their digging. Common burrow sites include areas beneath dense shrubs, overgrown vegetation, wood stacks, and debris piles, which shield the burrow entrance from predators and human disturbance.