How to Tell If You Have Rats
Rats are cautious, nocturnal animals. Most people never see a rat directly — instead, they notice the evidence rats leave behind. Knowing what to look for and where to check can help you catch a problem early, before it becomes a full infestation.
The brown rat (Rattus norvegicus) is the species responsible for almost all rat problems in UK homes and gardens. They are larger and more destructive than mice, and their signs are distinctly different.
Rat Droppings
Droppings are the most common and reliable sign of rat activity. Rat droppings are dark brown or black, roughly 10–14mm long, and tapered at the ends — often compared to a large grain of rice.
A single rat produces around 40 droppings per day. You are most likely to find them along walls, behind appliances, under sinks, in loft spaces, and near food storage areas.
Fresh droppings are dark and moist. If they are grey, dry, and crumble when touched, the activity may not be recent — but it is still worth investigating.
Scratching and Gnawing Sounds
Rats are most active between dusk and dawn. Scratching, scurrying, or gnawing noises in walls, ceilings, under floors, or in the loft are a strong indicator of rat activity.
Brown rats are strong swimmers and often enter properties via the sewer system. If you hear splashing or scratching from inside a soil pipe or toilet, it is possible a rat has entered through the drainage system.
Gnaw Marks and Damage
Rats must gnaw continuously to keep their incisor teeth short. This means they chew through wood, plastic, aluminium, and even soft metals. Look for gnaw marks on door frames, skirting boards, cables, food packaging, and pipe casings.
Gnaw damage to electrical wiring is particularly dangerous as it creates a fire risk. If you find chewed cables, have them inspected by an electrician alongside addressing the rat problem.
Grease Marks (Smear Marks)
Rats follow the same routes repeatedly, pressing their bodies against walls and skirting boards as they travel. The grease and dirt in their fur leaves dark smear marks along these runs.
Smear marks are most visible on light-coloured surfaces — painted skirting boards, plasterwork, and around pipe entry points. Well-established runs will have a noticeable build-up.
Burrows and Nesting
Brown rats are burrowers. Outdoors, look for holes roughly 6–9cm in diameter near foundations, under sheds, next to compost bins, in banks, or beneath decking. Active burrows will have smooth, compacted entrances with no cobwebs.
Indoors, rats nest in loft insulation, behind wall cladding, under floorboards, and in seldom-disturbed storage areas. Nests are made from shredded materials — paper, fabric, insulation, and plastic.
Rat Footprints and Tail Marks
In dusty environments such as lofts and cellars, you may be able to see rat footprints and tail drag marks. You can test for this by sprinkling a thin layer of flour or talcum powder along suspected runs and checking for tracks the next morning.
How to Tell If It Is Rats or Mice
The most common confusion is between rats and mice. The key differences are:
- Droppings — rat droppings are 10–14mm long; mouse droppings are 3–8mm long.
- Gnaw marks — rat gnaw marks are larger and rougher; mouse marks are smaller and finer.
- Noise — rats produce heavier, more distinct scratching and thumping; mice produce lighter, faster scratching.
- Burrows — rats dig outdoor burrows; mice rarely do.
- Size — an adult rat is 15–27cm (body length, not including tail); an adult mouse is 3–10cm.
When to Get a Professional Inspection
If you are finding droppings in multiple locations, hearing regular nocturnal activity, or spotting gnaw damage, do not wait. Rats breed rapidly — a pair of rats can produce several litters per year, and the problem will escalate quickly.
A professional inspection from a qualified rat control technician will confirm whether rats are present, identify how they are entering, and recommend the right treatment. At BuzzKill, inspections are free and carry no obligation. Book a free inspection today.
Need professional help? BuzzKill offers fast, reliable rat control services across London and Essex.