Rats damage buildings by gnawing through walls, pipes, ducts, and electrical wires - often causing fires. They eat and urinate on food and can carry dangerous pathogens and parasites. This rat-control guide will show you how to get rid of these little furry hazards for good.

1. Rat identification

It's important to first figure out which rodent you're dealing with. The most common types are Norway rats, roof rats and house mice. Use the following lists to identify your pest.

Norway rats:

• Grow up to 16" (40cm) long
• Nests at ground level
• Tail is shorter than body and head combined

Roof rats:

• Grow up to 15" (38cm) long
• Nests high in trees, foliage, walls and attics
• Tail is longer than body and head combined

Maybe they're mice?

Baby rats can look confusingly similar to house mice. You can tell them apart by looking at their heads and feet. Mice have much smaller heads and slimmer feet than baby rats. If you've located one rodent, there are sure to be more. Search for the largest droppings you can find. Adult mice leave cylindrical droppings up to 1/4" long and rats leave cylindrical droppings up to 3/4" long. You can also examine any entry-holes that have been gnawed into walls, mice will gnaw holes up to 1 & 1/2" large while rats will gnaw holes 2" and larger. If you're still not sure, sprinkle a little talcum powder on surfaces along walls where you think there's rodent activity then wait a few days. If you have rodents in that area you will see sets of tracks appear in the powder. Mice leave tracks that are approximately 1/2? wide while rats leave tracks up to 3? wide.

Other signs of a rat infestation include:

• Urine dribbles left in high traffic areas, usually near walls and other objects. The residues will glow under a black light.
• Dirty 'rub' marks along the sides of vertical surfaces that they often run along.
• Gnawing damage and debris, especially around food stores.
• Entry-holes gnawed into walls.

2. Eliminate the sources of the rat infestation

If you've decided that you have mice, read how to get rid of mice. If you believe them to be rats then keep on reading. We will start by inspecting every square inch of your home from the basement to the attic. Look for all signs of rats; gnawing damage, urine dribbles (Can be found with a black light), dirty smudges, feces, and entry holes. Record everything you find on a piece of paper and if you can, plot them on a map so you can get an idea of where they may be centered within the structure. Plug any entry-holes that you find with crumpled paper and return in a day to see if the paper has been disturbed. If it has, you have found an active hole. Mark them on your map and continue to the next step.

Remove rat-friendly food sources

Rats will eat any kind of food you have from seeds to yesterday's leftovers. You must overhaul any organic material storage areas inside of your home. Store all of your foods in metal or glass containers (no plastics) with tight-fitting lids. This applies to everything that is not stored in a refrigerator. Any food suspected of being touched by rats should be thrown away immediately. Fresh fruits and vegetables go in the fridge and pet food should be covered and put away between feedings. Invest in an metal garbage can that has a tight-fitting lid and refrain from throwing any organic wastes into it. Instead, rinse them off and store them in a large, sealable plastic tub and either bury the material or throw it away when you take out the trash. You should also consider using metal trash cans outdoors with bungee cords thru the handles to hold the lids on. If you choose to bury your organic wastes, do so at least a foot deep and then place a board or something heavy over the area as rats, dogs and raccoons can easily dig it back up. Outside, keep bags of seeds and pet foods elevated or sealed tightly in lidded metal garbage cans. If you have bird feeders (Learn how to make an eco bird feeder), fruit-bearing or nut-bearing trees, clean up any fallen material daily as these can easily feed a population of rats. Animal feces is also a food-source so collect and bury your animal's waste. If you have dumpster's near by, go inspect that any drainage holes near the ground are screened to prevent rats from feeding and put up a sign reminding people to clean up any spilled trash due to the rat problem.

Eradicate their shelter and cover

Rats can get everywhere, they climb wires, pipes, even vertical surfaces. They can swim underwater and jump up to three feet. Rats can gnaw through almost anything (including thin or weak metals) and can squeeze through holes as small as 1/2"! They prefer to forage in areas high in clutter, so clean any place that fits this description. The less clutter you have, the less places rats can hide. You will undoubtedly find indicators of rats as you work your way through the house - as you do, mark them all on your map so you'll have a cohesive picture of the areas that are frequented when it's time to put out traps.

Block all methods of home entry

Rats are very talented at getting into human structures. Norway rats can come up from sewer lines and actually swim up and out of toilets and drains. Roof rats have been known to run along electrical lines and onto roofs where they find entrance into the house and take up residence in attics. Both are good climbers, burrowers, and can gnaw through almost anything. When rat-proofing your home you must be thorough! Begin your hunt for possible points of entry outside around your foundation. Fill any holes or crevices with a generous amount of mortar mixed with finely broken glass. The glass will keep rats from digging out the mortar before it dries. Alternatively you can use steel or aluminum plating. Inspect all exterior walls to a height of at least four feet. The basement's next (if you have one). Fill cracks and holes in the foundation and secure any open drains with strong metal screens. Look for places where pipes and wires enter the building and ensure there is no space for a rodent to squeeze in - remember, 1/2" is all it takes. If you're feeling ambitious, there are many structural modifications that you can make to fortify your home against rats. From pouring concrete, to digging a trench around your property and filling it with gravel to discourage burrowing. If you get to this point, you may want to first call in a professional for an experienced opinion as this can be time consuming and costly.

3. Eradicate the current rat population

You've now limited their food and mobility - so the population will begin to shrink in proportion to the quality of your previous work. If your neighborhood was the source of your infestation, they will return so it's imperative that you keep up the habits discussed in the earlier sections. It's time now to take direct measures to kill off the remaining rodents. This section will only deal with lethal traps because rats are destructive and disease carriers and should not be set free anywhere near people. When selecting baits for your chosen traps, use some of the food they were previously stealing and don't be afraid to experiment. If one bait isn't working, try another. Rats have a knack for replenishing their numbers. When populations start to dwindle, more babies are produced per litter meaning speed is the key to eliminating the remaining few. Speeeeeeeeed.

Rat traps: How to kill rats

Never handle a dead rat with your hands - they can carry many dangerous diseases and so can their parasites (Remember the black plague?). Instead use a set of tongs or a shovel. Place the rat in a plastic bag and seal it before tossing. Always handle traps with gloved hands to keep any pathogens off of you as well as to keep human smells off of the traps. Use the map you made earlier to choose good trapping locations and mark off each kill as it occurs. Lay out the unset but baited traps for a few days to get the rats comfortable with feeding from them and when you do set them, use as many traps as possible to try to stamp out the population ASAP. What do rats eat? Hot dogs, liver, bacon, fruits, raisons, marshmallows, breads, and peanut butter + oatmeal. Snap traps Snap traps work very well on rats, be sure to get the big ones. Spring for the traps with wide trigger plates so the rat only needs to step onto the trap to spring it. Bait these with bacon, hot dog, or liver tied to the trigger with string to ensure that the trap is sprung. Set these traps against walls with the trigger plates facing the wall so the rats are more likely to run into them (remember that rats run along the sides of things and rarely out into the open). If your rats are trap shy, you can hide them by burying them in trays of sawdust. These traps can also be nailed to walls and boards, just don't put them anywhere a child or non-target animal can get to them and check daily for kills. Glue boards Glue boards are useful for capturing baby rats, but not so much the adults. Kill any rats captured in these traps by submerging them in soapy water. Be sure to keep them well away from pets and children. These can be found inexpensively in most hardware stores and online. Zapper traps Zapper traps work by luring rodents inside a small structure and delivering a lethal electric shock. They work poorly on rats due to their large sizes - the shocks just aren't strong enough. The most popular version is The Rat Zapper, but Victor makes a less expensive model that seems to work just as well. Ultrasonic (plug in) devices The federal trade commission has stated that these devices are ineffective in controlling rodents, that they do not cover the advertised area, and that they do not prevent rodents from entering an area. Furthermore there have been no studies that prove these devices work. While an ultrasonic device may provide some deterrence it is likely that the rodents will get used to the sounds it makes and eventually ignore it. Just read some of the experiences people have had with these.

Poisons

Poisons have proven ineffective again and again when combating rats. They do work to lower populations, but as soon as the poisons are removed the population levels shoot back up to where they were before unless the environmental causes are dealt with. Poisons also cause rats to die in walls and other hard to reach places, and rotting rats cause horrible smells and attract pest insects. Rats are infamous for building immunities quickly, so save the poisons as a last resort, and if the time comes call a professional. One bit of advice though, stay away from warfarin, many rat species are already immune to it.

Predators

• Dogs - Dogs may kill an occasional rat, but they are little more than a deterrent to keep rats hidden.
• Cats - Cats have a better track record at killing rats, especially strays - but are also little more than a deterrent.
• Barn Owls - Barn owls are extremely efficient at getting rid of rats. Consider erecting a nesting box to attract some onto your property.