Norway Rats in Delaware: How to Spot Them and Get Rid of Them

What they look likeSignsAre they dangerous?How we treat themPreventionFAQ

What do they look like?

Norway rats are much bigger than mice, about 7 to 9 1/2 inches long. They're brown with scattered black hairs and a gray to white belly, and the tail is shorter than the head and body together. Outside, they dig burrows in soil, under slabs, and in garbage and woodpiles. Inside, they nest in basements and piles of debris. Their droppings are capsule-shaped with blunt ends, unlike the pointed droppings of mice.

Signs you have them

• Capsule-shaped droppings with blunt ends
• Greasy, dark rub marks along walls and foundations
• Gnaw marks that look rough when fresh and smooth when old
• Burrows in soil, under slabs, or in woodpiles

Are they dangerous?

Rats can do real damage. They gnaw through plastic and lead pipes. The CDC lists hantavirus, leptospirosis, salmonellosis, lymphocytic choriomeningitis, and rat-bite fever among the diseases rodents spread directly, through contaminated air, contaminated surfaces, or bites and scratches. Rats can also bring fleas indoors.

When are they active?

Norway rats typically move indoors in autumn and nest in basements and debris.

How Wolfe treats them

We start by finding where the rats live and how they're getting in, checking burrows, the foundation, crawl spaces, and where pipes and wires enter. Then we follow the CDC approach of seal up, trap up, clean up, setting traps where they're active and sealing openings with our rodent exclusion service. All of our work comes with a 30-day warranty. If pests come back within 30 days of a treatment, call us and we'll come back out at no extra charge.

How to keep them out

• Move firewood away from the house.
• Seal small openings with steel wool, and larger ones with metal, cement, or hardware cloth.
• Fix leaks in basements and crawl spaces.
• Keep food and garbage sealed.

Common questions

Sources: PestWorld (NPMA): Norway Rats; CDC: Rodent Control; CDC: How to Seal Up

Last reviewed October 2026 by Wolfe Pest Control.