Worldwide, rodents such as rats and mice spread over 35 diseases. These diseases can be spread to humans directly, through handling of rodents, through contact with rodent feces, urine, or saliva, or through rodent bites. Diseases carried by rodents can also be spread to humans indirectly, through ticks, mites or fleas that have fed on an infected rodent.
Who Has Rats and Mice?
Every country has rats and mice. Most kinds live in woods and fields, but three kinds live with people: the house mouse, Norway rat and roof rat. Rats and mice will move in with the best of people.
What Do Rats and Mice Do?
Rats and mice spoil your food, carry diseases, and they’re dirty. They soil your house with their droppings. They like open garbage cans, dumpsters, sewers and rubbish heaps. If you see a rat or mouse, you can be sure there are many more. They usually hide by day and come out at night. Mice are about 3 inches long, not counting the tail. Rats are much larger — up to a foot long, not counting the tail.
Rats and mice are curious. They eat a variety of foods, including grain and seed, nuts, meat, candy and processed cereal. They have poor eyesight but excellent senses of smell, taste and touch. They are mainly active at night.
House mice have a naked tail; native mice have a slightly furred tail. Roof rats are sleek and graceful; their ears extend past their eyes. Norway rats are large and heavy bodied; their ears do not reach past their eyes and they can weigh more than a pound.
Do You Have Rats or Mice? Look for…
- Droppings: Mouse droppings are about the size of rice grains; rat droppings are about the size of a raisin.
- Tracks: Scatter a small patch of flour or talcum powder on the floor along the wall or in likely places. Put a cracker or a piece of bread spread with peanut butter in the middle of your “tracking patch.” Check for tracks the next day.
- Burrows: Check in weedy places, under boards, under dog houses and near garbage cans or dumpsters.
- Gnawings: Any little hole with chewed edges is a sure sign. Check your pantry for chewed packages. Look for shredded paper. Look for tooth marks.
- Sound: Listen for gnawing or scratching in walls or attics, especially at night.
- Nests: Chewed paper or cloth (including gloves, carpet, clothes) are often found in boxes, drawers, basements or attics.
- Odor: A musty odor usually indicates mice, not rats, are present.
Rats and mice breed fast. A mouse can have several young when she’s two months old. Then, two months later, her young will breed. In the meantime, the mother will produce another litter. So you must keep working to get rid of them. Certainly you can get rid of most of them.
Take Away Their Food
Keep garbage in tightly covered cans. Feed dogs and cats in a dish, then take up the food they don’t eat. Don’t leave it out for rats and mice.
Destroy Their Homes
Remove trash, old boards, weeds and junk cars. Rats and mice like to hide in such places. Don’t pile wood against the house. Store wood and other materials at least a foot off the ground.
Close Their Holes and Entryways
Keep doors closed. Cover windows with screens. One-fourth inch or smaller mesh will keep rats and mice out. Keep floor drains tightly sealed. Cement or caulk around pipes and cables where they pass through walls. Mice can get through any hole that will admit the tip of your little finger. Seal small holes and cracks by stuffing them with stainless steel scouring pads, then caulk over them. After you kill rats and mice, close burrows with a shovelful of earth. Then stamp it shut. If a burrow is reopened, you know you still have rats or mice.
Use traps, not poison baits, inside houses. Poison baits are more dangerous. Also, poisoned rats and mice will die and stink in walls and attics. Use plenty of traps in a room. Put them along the wall, in cupboards and drawers, and in other places where mice might run. Make it so a mouse won’t travel more than 5 or 10 feet to find a trap. Do this because a well-fed mouse likes to stay home. He may live for weeks in one corner of a room. Don’t expect him to cross the room to find your trap. A mouse likes to run along a wall. Set traps with the bait treadle across his path at a right angle to the wall. Don’t set the trap parallel to the wall and force mice to go around or over the trap to reach the bait. Make it easy for them. Snap traps are the cheapest, so use plenty. Multiple catch traps work fine, but remember to use enough of them. Sticky traps are as good as snap traps and easier to use. Ask your store owner to stock them. What bait is good? Mice like peanut butter, bacon or anything tasty with a strong odor. Have you caught them all? It’s hard to say. Leave the traps in place for a few weeks. How did the mice get into the house? Discover how they got in and close the openings. Once you’ve rid your house of mice, can you relax the forget them? No. New mice will find you. Save your traps. Be ready to go to war with mice again. Give rats the same treatment, but use the larger rat traps. Set them only in places where children won’t get into them. For rats, you need fewer traps. A dozen for an average house is usually enough. Rats are smarter and harder to catch than mice.
Use poison outside the house only if you can keep it away from pets and children. A locked shed or garage is a suitable place. Poison bait tastes good; it often has sugar in it. Don’t be careless with it. Many good poisons are on the market. Use poisons with warfarin, pival, fumarin, chlorophacinone or diphacinone. They are not quite as hazardous as the quick-kill or single-dose poisons. These poisons are available as poison food or poison water. Mice or rats need to eat them each day for about a week before they die. Set out poison bait stations in places where you see signs of rats. Get a sturdy wood, metal or cardboard container. Cut 3-inch diameter holes in opposite sides at ground level. Fill a small container with a pound of poison bait. Put it inside the bait box. Add bait each day to keep it full. Don’t let rats empty the bait container. They must feed from the bait each day or they may not die. Use the same technique for mice, but you can use a smaller bait box and less bait. Mouse holes in a bait box can be about 1 inch in diameter. Use disposable plastic gloves to handle dead rodents you find. Throw them in the garbage or bury them. If, after a few weeks, rats and mice are no longer feeding at the bait station, remove the bait. Save it in a clean, sealed container for your next rodent problem. Don’t leave bait out for a long time. It will mold, spoil or cause a poisoning accident.
Organize Against Rats and Mice
Get together with your neighbors. Clean up several yards in the same area. Trap and poison neighbor-hood rodents at the same time. This way, re-infestation from nearby rodents is less likely.
Rats and mice may feed from bird feeders. A squirrel guard will also deter mice and rats. Sound or flashing lights have almost no effect repelling rats or mice. Taste and odor repellents are not registered for rats or mice. Non-native rats and mice are not protected by law. Shooting is not generally effective for controlling rats and may be hazardous. Sanitation is the best method of control. Trapping is cost effective, generally safe and very effective if done properly. Fumigants or gas should be used only by licensed pest control operators. Rats and mice stay near home. Norway rats may travel only in an area 100 to 150 feet in diameter each day. Rats and mice and their droppings, urine and fleas can transmit diseases to humans. Use a dust mask and disposable gloves when handling dead rodents or cleaning up after them.
Attention!! Pesticide Precautions
- Observe all directions, restrictions and precautions on pesticide labels. It is dangerous, wasteful and illegal to do otherwise.
- Store all pesticides in original containers with labels intact and behind locked doors. Keep pesticides out of the reach of children.
- Use pesticides at correct label dosages and intervals to avoid illegal residues or injury to plants and animals.
- Apply pesticides carefully to avoid drift or contamination of non-target areas.
- Surplus pesticides and containers should be disposed of in accordance with label instructions so contamination of water and other hazards will not result.
- Follow directions on the pesticide label regarding restrictions as required by state and federal laws and regulations.
- Avoid any action that may threaten an endangered species or its habitat. Your county extension agent can inform you of endangered species in your area, help you identify them and, through the Fish and Wildlife Service Field Office, identify actions that may threaten endangered species or their habitats.
- Original publication by Jeff Jackson, Wildlife Specialist (ret.), Warnell School of Forest Resources. Illustrations from U.S. Fish and Wildlife Service and other sources.