Rodents can be a challenge in both urban and rural settings, but, vigilance in applying integrated pest management strategies can keep populations low. Knowing some of the key characteristics of rats helps in developing a management plan. They can climb most surfaces and jump up to 36 inches. They are shy, but also inquisitive, initially avoiding new objects, but in time investigating them. Rats are nocturnal—out from dusk until dawn. They are not active the entire time but have multiple periods of activity at night. Their poor eyesight causes them to rely on hearing, touch, and scent. Rats’ incisors grow so rapidly they must constantly gnaw on everything to wear them down. Rats begin to breed at three months of age, producing up to 12 rats per litter and four to six litters per year. A pair of rats and their offspring could produce 1,500 more rats in only one year if they all survived. Their average lifespan is one year. Adult Norway rats (Rattus norvegicus) range from 12 to 18 inches long, nose to tail tip. Their gray to brown bodies are compact and heavy. They have relatively small eyes and ears, and their tails are generally about half their body length. Norway rats are prodigious burrowers. They eat garbage, meat, fish, cereals, seeds, pet food, and a wide variety of other substances. To determine if there is a problem, look for these signs: evidence of gnawing, rat droppings (capsule shaped and 1⁄2-inch to 3⁄4-inch long), tracks, and large burrows along building walls.
Management Strategies for Norway Rats
These strategies are most effective when there is a community-wide effort.
- Minimize nesting sites by removing junk and storing materials 12 to 18 inches off the floor and away from walls.
- Limit food by storing bulk birdseed, chicken feed, and other potential sources of food in metal containers. Store chicken feed in a metal container each night. Feed pets indoors. Remove spilled seed from beneath bird feeders. Clean up spilled food. Use a tight lid on garbage cans.
- Practice good sanitation. Well-swept floors and mowed turf make it easier to detect problems and also force rats into exposed settings, making them more vulnerable to predators such as dogs and owls.
- Make structures rodent proof. Seal off all potential entryways.
- None proven effective.
- Go to Animal Damage Control at the following link for rodenticide suggestions for Norway and other rats.
- All chemicals should be applied according to the label's directions.
- Rodent-killing as the only control strategy is expensive and effective for only a short while. Unless the conditions that allowed the rats to thrive are changed, new rats will soon move in.
- Control is most effective in winter when rat populations are lowest.
- Unless the rodent infestation is severe, it is best to sanitize and rodent-proof prior to killing rodents.
- When trapping, traps may be baited or not. Bacon, peanut butter, bread, and nutmeats make suitable baits. Place traps in areas of rodent activity, 15 to 30 feet apart, in places that are inaccessible to pets and children. Traps have several advantages over rodenticides: (1) They are more affordable as they can be used many times. (2) There is no chance of accidentally poisoning a child, a pet, or another non-target animal. (3) The rat is killed instantly in the trap. (4) There is no chance that the trapped rat will provide an unintended dose of poison to a hawk, owl, or another predator.