Knowing whether you have rats or mice makes a significant difference to how you approach the problem. The two species behave differently, require different treatment strategies, and present different levels of risk. This guide will help you identify which you are dealing with and what to do next.

Identifying rats

The brown rat (Rattus norvegicus) is by far the most common rat species in Scotland. Key identification features:

• Body length 20-25cm, tail 17-20cm. Total length up to 45cm.
• Brown or grey-brown fur on the back, paler underside.
• Blunt nose, small ears relative to head size, thick tail.
• Droppings are dark brown, 10-12mm long, tapered at one or both ends.
• Burrows in soil, under decking, and along fence lines.
• Tends to follow fixed routes along walls and through gaps.

Identifying mice

The house mouse (Mus musculus) is the most common mouse species found indoors in Scotland:

• Body length 7-10cm, tail 7-10cm. Total length up to 20cm.
• Grey-brown fur, slightly paler underside.
• Pointed nose, large ears relative to head size, thin tail.
• Droppings are dark brown to black, 3-6mm long, rod-shaped with pointed ends.
• Nests in wall cavities, under floorboards, behind appliances, and in loft insulation.
• More exploratory than rats. Will investigate new objects in their territory.

Early signs of an infestation

The earlier you spot an infestation, the easier it is to deal with. Look for:

• Droppings along walls, behind appliances, in cupboards, and in loft spaces.
• Gnaw marks on food packaging, wooden structures, cables, and pipework.
• Scratching or scurrying sounds from inside walls, under floors, or in the loft, particularly at night.
• Smear marks along walls where rodents repeatedly brush against surfaces.
• Nesting material: shredded paper, insulation, or fabric in hidden areas.
• A distinctive musty or ammonia-like odour in areas of high activity.

What to do if you find signs

Do not wait to see if the problem resolves itself. Rodent populations grow quickly, and an infestation that is manageable in September can be well-established by November. Over-the-counter products can provide temporary relief but rarely address the root cause. A professional survey will identify the extent of the infestation, the entry points, and the most effective treatment approach. Pest King offers free no-obligation quotes for residential and commercial properties across Aberdeen, Dundee, Angus, Perth and Stirling.