Identifying the presence of rats in a yard often begins with recognizing their primary means of shelter and travel: the burrow. A rat hole is the entrance to an underground tunnel system that provides protection, nesting space, and a safe route between food and water sources. The two species most commonly encountered in North America are the Norway rat, a prolific ground-burrower, and the Roof rat, which prefers elevated nesting. Visual identification of these holes is the first step in assessing a potential infestation and determining the appropriate course of action.
Key Physical Indicators of Rat Holes
A rat burrow entrance is typically larger than that of smaller rodents. The opening is usually round or slightly oval, with a diameter ranging from approximately two to four inches.
The edges of an active rat hole often appear smooth and well-worn due to frequent use. Consistent traffic compacts the dirt around the perimeter, rubbing away loose soil. Holes that are currently in use will also be clear of debris, such as leaves, cobwebs, or overgrown vegetation, confirming recent activity.
Preferred Locations for Rat Burrows
Rats choose burrow locations based on security, proximity to resources, and cover from predators and weather. They exhibit thigmotaxis, a preference for traveling close to vertical surfaces, making areas near building foundations common choices. Burrows are often situated along the edges of structures, such as under decks, sheds, porches, or concrete slabs and sidewalks, which offer structural protection.
Burrows are frequently found near dense ground cover, overgrown bushes, or woodpiles. Proximity to a reliable food or water source is another attractor, leading rats to establish homes near compost heaps, garbage bins, or poorly draining areas.
Secondary Evidence Surrounding the Entrance
The physical hole is only one piece of evidence; a closer inspection of the surrounding area often provides definitive proof of a rat infestation. Rats repeatedly use the same routes, which creates visible, narrow paths known as runways connecting the burrow to food or water sources. These trails often appear flattened in the grass or worn smooth in the dirt, and may be dark or greasy from repeated contact with the rats’ bodies.
The entrance area may contain a fan-shaped pile of loose, excavated dirt pushed out during digging. Unlike the mounds of other digging animals that cover the hole, the rat’s dirt pile is typically scattered outside the open entrance. Finding rat droppings near the hole confirms the species; they measure about one-half to three-quarters of an inch long and have a blunt, capsule-like shape.
Rats rely on established paths, causing them to leave dark, greasy smudges, or rub marks, along foundations or walls near heavily used exit points. A strong, musky odor may also be noticeable in areas with a heavy infestation, resulting from frequent urination along their travel routes.
How Rat Holes Differ from Other Pests
Distinguishing a rat hole from that of another yard-dwelling animal requires attention to the size and structure of the opening. Vole holes are noticeably smaller than rat burrows, typically measuring only one to one and a half inches in diameter, and are clean-cut with no obvious dirt pile. These holes are often found in open grassy areas, differing from the rat’s preference for covered locations along structures.
Mole activity is characterized by raised, visible ridges or tunnels that run across the yard, rather than open holes leading to a den. The mole’s signature feature is the volcano-shaped mound of soil, created when the animal pushes dirt up to the surface, capping the tunnel entrance. Chipmunk and ground squirrel holes are generally around two inches, closer to the smaller end of a rat burrow, but their entrances are usually very clean and lack the oily rub marks left by a rat’s fur.
A practical way to confirm if a burrow is actively occupied is to perform the “plug test.” This involves temporarily filling the hole with loose soil or crumpled newspaper and checking on it the next day. If the material has been quickly pushed out or removed within 24 to 48 hours, it indicates the hole is currently being used, most likely by a rat if the opening is large and well-worn.