How to tell if you have rats

What rat droppings look like

A rat leaves about 40 droppings a day. They are chunky and spindle or sausage shaped, about 9 to 14 mm long. Fresh droppings are dark, soft and shiny. Old ones turn grey and crumble when touched.

Guides disagree on the exact size, with some saying 10 to 14 mm, so treat the length as a range. What matters more is the shape: thick and blunt-ended, not thin and pointed. Wear gloves and wash your hands afterwards if you clear them.

Other signs of rats

Droppings are only one sign. Check for:

• gnaw marks on skirting boards, cables and pipes
• greasy grey-brown smear marks along walls where rats run
• nests of shredded paper, fabric or insulation
• burrows about 6 to 10 cm wide near sheds, decking and compost heaps
• scratching in walls or the loft at night
• a musky, ammonia-like smell

Rats can squeeze through a gap the size of a 50p coin, so a small hole near a pipe or air brick is worth marking.

Where to look

Rats follow the same routes each night, so look along edges. Check behind the cooker and fridge, under the sink, in cupboards that hold food, and in the garage and sheds. In the loft, look in the insulation and along the joists for droppings and shredded nests.

Outside, look beside sheds, under decking and around compost heaps for burrows, and along fence lines for smear marks and trodden runs. A torch and a few minutes at dusk will tell you more than a daytime glance. Note where you find each sign, because that map helps a professional. A dead rat in a wall or cavity gives off a smell you cannot miss.

Rat or mouse?

Mice are the usual mix-up. Mouse droppings are about 3 to 6 mm and pointed, like dark rice grains, so a rat's are roughly twice the length or more and much thicker. Mice scatter droppings through drawers and cupboards, while rat droppings gather along runs and near food. See how to identify mice for the full comparison.

Squirrels are the other lookalike in a loft. They are noisy by day, and their droppings are about 8 to 12 mm, so size alone will not settle it. Noise at night points to rats or mice; noise in the day points to squirrels.

When rats are most likely

Indoor activity rises from October to March as it turns cold, although towns and cities see rats all year. If you find signs, the next step depends on where they are. Read about rat control by a professional, try the legal DIY methods, or check what it costs.