Finding mysterious holes in your yard can be worrying. While squirrels, moles, or even insects sometimes create burrows, rats are also skilled diggers that leave behind tell-tale signs.
Norway rats, the species most often found in Canadian cities and towns, prefer to build burrows close to reliable food and water sources. These tunnels not only damage lawns and gardens but also bring health risks if left unchecked.
This article is for general purposes only. Before taking action, it’s important to confirm whether rats are truly to blame. Misidentifying the culprit could lead to ineffective solutions or harm to non-target animals.
1. Burrow Entrances
The signature calling card of Norway rats is their entrance holes measuring roughly the diameter of a golf ball or tennis ball. These openings typically appear near solid structures that offer protection.
Rat burrows often cluster around foundations, garden sheds, compost bins, or dense vegetation. Unlike rabbit or groundhog holes, rat entrances look cleaner and more precisely formed, without scattered soil spreading widely around the opening.
2. Smooth, Well-Worn Paths
Creatures of habit, rats create distinctive highways through your garden. These narrow trails, about 5-8 cm wide, appear as flattened channels through grass or dirt where vegetation has been trampled down.
Morning dew often highlights these paths, making them easier to spot at daybreak. Rats prefer traveling along walls, fences or other boundaries rather than open spaces, so check these areas first when hunting for their runways.
3. Fresh Soil Around Openings
Active rat burrows feature small, neat piles of freshly excavated dirt right at the entrance. The soil appears finely granulated rather than clumped, often forming a fan-shaped pattern extending from the hole.
Check after rainfall. Rats frequently clear their tunnels following wet weather, pushing out fresh soil. The texture differs from mole hills, which create larger, more conical mounds, while rat excavations stay closer to the entrance and appear more scattered.
4. Droppings Near Tunnel Entrances
Rat droppings tell a revealing story about your unwanted visitors. Fresh droppings appear shiny, dark, and moist, resembling grains of rice about 1-2 cm long with pointed ends.
They typically cluster near burrow entrances or along rat pathways. Norway rat droppings differ from mouse droppings, which are much smaller (pencil-lead sized) and from squirrel droppings, which are more rounded and lighter in colour.
5. Gnaw Marks On Garden Items
Rats have constantly growing teeth that require regular filing down through gnawing. Garden hoses, wooden handles, plastic containers, and even irrigation lines often bear the brunt of this dental maintenance.
Look for parallel tooth marks about 2mm wide on these items, especially near burrow locations. Unlike rabbit or squirrel damage, rat gnaw marks appear in rough patches rather than clean cuts, leaving behind a distinctly ragged edge with visible tooth grooves.
6. Food Debris Near Holes
Rats aren’t tidy eaters. They often drag food items back to their burrow entrances, leaving behind shells, husks, or partially eaten fruits and vegetables. These dining areas become scattered with evidence of their varied diet.
Look for gnawed produce with distinctive incisor marks or piles of empty seed husks. Unlike birds or squirrels that leave clean breaks, rats create ragged, torn edges on plant material and leave behind half-eaten items that they’ve sampled and abandoned.
7. Distinctive Musky Odour
Your nose can detect what your eyes might miss. Active rat colonies emit a distinctive musky, ammonia-like smell that becomes noticeable around heavily used burrows.
This scent comes from their urine, which they use to mark territories and communicate with other rats. On warm, humid days, the odour intensifies near active burrow systems. Many professional exterminators identify rat infestations by this characteristic smell before visual confirmation.
