7. Gnaw marks

While holes in the wall are among the most common signs of a pest infestation, many homeowners don’t usually look for evidence of pests gnawing or chewing.

For example, rats will gnaw on just about anything they come across, so keep an eye out for chewed-up cardboard boxes, window sills, old newspapers or magazines, baseboards, upholstery, electrical wires, or even drywall. In other words, yes, rats are some of the worst pests you can deal with in your house.

Squirrels, raccoons, and other larger pests are also known to chew through solid materials like wood, so make sure you search for gnaw marks when looking for signs of a pest infestation.