Non-native, feral rodents, such as the Black Rat, aka Roof Rat (Rattus rattus), Brown Rat, aka Ship Rat or Norway Rat (Rattus norvegicus) and House Mouse (Mus musculus) are destructive pests that can cause considerable damage to a home and garden if they’re not controlled.
Inside the home they may spoil and contaminate food, physically damage clothing, documents, structures and furniture by gnawing on them, and also damage electrical wiring which may start house fires.
In the garden, these rodents will eat various food crops, and also chew through protective netting that’s put in place keep out other pests such as birds and possums.
Are rats and mice lurking around? For some simple ways to identify their presence, see the article: How to Tell If You Have Rats and Mice in Your Home or Garden
Why Are Traps Better for Eliminating Rats and Mice?
When people discover that they have a rat or mouse problem, they often make the mistake of disregarding traditional snap traps as the first choice for controlling the rodents.
It’s important to keep in mind that this style of traps has survived the test of time due to their effectiveness when used correctly. The oldest record of such design is the Egyptian clap bow trap (approximately 8,000 years old), which was used to trap birds, and closely matches the design of modern all-wire snap-traps.
With the clap bow trap, instead of a spring, the energy is stored in a tightly twisted cord known as a ‘skein’ which applies tension to the movable upper wood jaw that is held in place by a trigger stick. The trigger stick is tied at one end, with the other end that’s pointed like a pencil poked loosely through a cord loop at the bait end. It works in exactly the same way as the modern traps do.
The conventional spring-loaded snap trap mounted on a block of wood first appeared in 1884, and is still used extensively to this day because it’s both inexpensive and highly effective.
Using rat and mouse traps takes a little effort, but the advantage of traps is that they provide positive confirmation that the control efforts were successful. They also allow for the convenient disposal of the dead rodent, preventing the problem of poisoned rodents dying in or under buildings.
Overall, traps can be used to eliminate rats and mice more cheaply, safely, humanely and effectively than poison baits.
What Are the Disadvantages of Poison Rat and Mouse Baits?
Laying out some poison bait to deal with a rodent problem may seem like an easy and convenient, albeit expensive and slow solution, but there are other issues to consider:
- Poison rodent baits are dangerous to pets and native wildlife, who may eat the baits or the poisoned rodents. With pets this may lead to a very expensive emergency visit to a veterinarian!
- Bait-shy rodents who are fussy or cautious about what they eat may avoid poison baits.
- Poison rodent baits are slow-acting, they’re usually based on anticoagulants, which cause internal bleeding, and take many days to kill rats and mice.
- Rodenticides based on warfarin, chlorophacinone, and diphacinone are known as multiple-dose anticoagulants, as they generally require an animal to eat multiple doses of the bait over several days.
- Others, such as brodifacoum, bromadiolone, and difethialone are known as single-dose anticoagulants, they’re more toxic, and a single feed can deliver a toxic dose, but the animal will still continue taking more bait for many days.
- There are non-anticoagulant poisons that work in different way, such as bromethalin and cholecalciferol (vitamin D3) (yes, it’s really vitamin overdose!) which act over a few days, or the more toxic, faster-acting zinc phosphide (signs of toxicity in 4-18+ hours) and strychnine (signs of toxicity 15min – 2 hours) which are only for agricultural use and are not legally available to the public.
- When rodents are poisoned, they become sick and seek out shelter, often hiding in roof spaces, within walls, or under the floor, where they may die, causing extremely unpleasant odours, especially in summer!
In this article, we’ll explain the best ways to use the various types of snap traps to humanely, quickly and effectively eliminate any rat or mouse problem, inside or out.
Do Rats and Mice Spread Diseases?
Rats and mice are a real health risk, they live in unhygienic environments, and have the potential to transmit diseases to humans. The most common disease transmitted by rats and mice is Salmonellosis (caused by the Salmonella bacteria), which is spread by eating food contaminated with rodent saliva or droppings (faeces).
They can also spread many other types of diseases through:
- Food or drinking water contaminated with rat/mouse urine, droppings, saliva or hair.
- Breathing dust contaminated with rat/mouse urine and droppings. (Always wear a mask when removing their nests).
How Does a Rat or Mouse Trap Work?
The most common type of rat and mouse traps use a spring-loaded striker (shown in orange) held back by a latch (shown in green) that is released when the animal depresses the trigger (shown in blue).
- The trap is baited first by placing food or some other attractant on the trigger.
- The trap is armed (set) by pulling back the spring-loaded striker 180 degrees against the force of the spring, and then holding it in place at the back of the trap with the hand.
- To lock the spring-loaded striker down, the latch (retainer bar, hold-down bar) is laid flat over the top of the spring-loaded striker to hold it in place.
- The trigger (with the bait attached) is raised slightly upwards, and the end of the latch is then poked through the hole on the trigger, locking the spring-loaded striker down.
- The hand holding back the striker can now be released. The spring forces the striker upwards onto the latch, which, in turn, forces the other end of the latch upwards against the slightly raised trigger that hold it in place.
- When the trigger is depressed by a rat or mouse, the latch disengages, freeing the spring-loaded striker, which swings over violently to swiftly dispatch the rodent.
Which Type of Rat and Mouse Traps Are the Best to Use?
Snap traps for rats and mice can be purchased from most hardware and grocery stores. With many new modern styles of snap traps now available, it’s often hard to choose. Each type of snaps traps has its advantages and disadvantages, which we’ll explain in detail below.
Traditional Wooden Rat and Mouse Traps
The simple, traditional wooden rat and mouse snap traps are the least expensive option, and even though they’re reusable, and can last quite a while, they’re so cheap that they can be treated as disposable items after bit of use if they get too dirty, as the wooden base is not easy to clean.
The springs are very strong on these types of traps, the wire striker bar gains a lot of speed by travelling a long distance in its 180-degree arc from one side of the trap to the other. When rodents are struck by the wire striker bar, this mechanism snaps their neck instantly or inflicts a major injury around that area that results in a very quick kill, making them more humane.
Plastic Rat and Mouse Traps
Some people prefer using the newer plastic snap traps because they’re easier to set and clean. Pressing the rear lever down sets the trap or releases the dead rat into the bin for easy disposal. The parts that make contact the rodent never comes anywhere near the rear half that’s handled by the person. Being plastic, any unpleasant stuff can be easily washed off. Other than springs rusting from being left too long in wet weather, these traps can last a very long time.
These snap traps also have very large plastic treadles (platform-style levers around the bait which act as a trigger) which makes them very sensitive, much more than other traps. They have a ‘hair trigger’, which makes them more effective, as even the slightest nudging of the bait can trigger the trap.
Their disadvantage is a lack of power. Their plastic jaws only move across a relatively short path, and don’t travel as far as the wire striker bar of a regular snap trap. As such, they don’t develop as much momentum and killing power. They do use a much stronger spring though, but it’s not always enough to kill a large rat outright, so the creature may struggle in the trap for a bit longer than necessary until it succumbs to its injuries.
How to Use Plastic Rats Traps Ethically by Double-Trapping
Do plastic rat traps sound too cruel? They can still be used humanely by employing a technique I call double-trapping, it’s an idea I came up with that works very effectively, 100% of the time.
To ensure quick, humane kills with plastic rat traps, set a regular trap (or two) next to them, and these traps don’t need to be baited. Any kind of struggle by the rat will trip the other trap, causing a double-trapping where the rat will be quickly finished off by the other more powerful trap.
I discovered this method by accident when I placed powerful metal wire traps alongside the more sensitive but weaker plastic rat traps. I’ve photographed this many times, where a single rat is caught in two traps a once, it’s overkill, and it really works.
Mice are small, delicate creatures, so it doesn’t take much to swiftly dispatch them, and any traps, including all the plastic ones, will effectively provide a quick kill. Some plastic traps are hybrid designs, that use a metal wire striker, which itself may have a plastic cover, as shown in the picture above.
I tend to avoid the disposable one-use single-kill plastic rat or mouse traps as they’re either not cost effective or environmentally friendly. In my opinion the use of disposable products is rather wasteful.
Metal Wire Rat and Mouse Traps
Metal wire traps are usually constructed of galvanised steel wire or sometimes even stainless steel to resist corrosion when used outdoors. These traps employ very strong springs, so they’re a bit harder to set, but whatever gets caught in them has an extremely quick, merciful ending.
The trigger is made of thin, stiff spring-wire, which forms a loop to hold the latch, and two prongs that hold the bait like a fork, making baiting easy.
The wire-frame design allows these traps to be easily secured. They can be pinned to the ground to resist movement, so the shock of snatching at the bait will make the trap more likely to trip. They can also be wired or tied in place to prevent larger animal carrying off the trap with the rodent in it.
What’s more important than the type of trap used is selecting the right baits to use, and also finding the best locations to the set the traps.
Top 7 Tip to Catch More Rats and Mice
Here are seven excellent tried-and-tested tips that will help you catch more rats and mice, and eliminate rodent problems much quicker!
Tip 1 – Don’t Handle Traps and Baits, Wear Gloves
Rats and mice have an excellent sense of smell, and will reject anything that has human scent on it! Humans and predator animals are a grave threat to rats and mice, so they remain extremely cautious in order to survive, and don’t ‘get used to human smells’ as some claim!
I remember watching a documentary where a huge nest of rats was found under a shed on a rural property. The rat catcher had a dog and a mink or ferret. As he explained, rather than run to safety, all the rats stayed frozen in place from fear because they smelled human and dog outside. The ferret or mink he used went back and forth systematically, eliminating the rats one by one in front of all the others. The rats could have all scurried away and most of them would have survived, but they instead chose to stay in place until every last one of them was killed. So strong was their instinct to avoid humans (and their dogs) that it led to their demise!
Always wear gloves when handling baits, and also when baiting and setting traps. A packet of disposable kitchen gloves is quite inexpensive. Even regular gardening gloves are better than nothing.
Tip 2 – Use Baits That Rats and Mice Like Most
Traps can be baited with a variety of foods, as rats and mice have quite a varied diet, but peanut butter is the most popular because it’s a very rich food with a strong smell that they find attractive, and it’s also very easy to use, and doesn’t smell bad over after many days.
The way to use peanut butter is to spread it onto small pieces of bread. Bread comes apart when it gets wet though, and tears away easily from the trap. To overcome this problem, use the bread crusts, they’re harder and chewier, so they stay a lot longer on the traps.
It’s possible to use a range of other foods for bait, and if we look at what rats and mice eat, it can give us many more choices in bait selection.
What Do Rats and Mice Eat?
House mice normally live outdoors in fields, and prefer to feed on grains, but usually eat a wide variety of foods.
- House mice require only 3g (1/10 oz) of food and 1.5g (1/20 oz) of water daily, but they don’t need to drink water and can survive on food alone if it has a high enough moisture content.
Brown rats (Norway rats) generally prefer to eat fresh meat, fish, and grain.
- Brown rats thrive in areas where garbage is accessible, and can survive quite well on an 30g (1 oz) of garbage or decayed food along with 30g (1 oz) of water per day.
Black rats (Roof rats) generally prefer vegetables, fruits and grain.
- Black rats consume 15-30g (1/2 to 1 oz) food from various sources along with 30g (1 oz) of water per day.
For baited traps to work, they rely on the rat or mouse being more attracted to the bait than any other available food. Since the bait must compete with other available foods, it’s important to remove any other available food sources if possible, and then select the best bait for the location. Where rodents are living on garbage or spoiled food, their preference would be for fresh food, so that would be a more attractive bait.
Listed below are some suggested rat and mouse baits that have been documented as being successful:
For all rats and mice:
- Whole nuts – don’t use these outside in open locations as they may also attract some birds!
- Peanuts (soak whole peanuts in water overnight) – caution as above!
- Peanut butter – remember to replace frequently as it goes rancid.
- Bacon squares
- Hard cheese
- Small wads of cotton, which they seek out for nesting material
- Dry rolled oatmeal
- Gumdrops, or other pectin-based gummy sweets
For Black rats (Roof rats):
- Raisins or grapes
Brown rats (Norway rats):
- Sardines packed in oil
Chocolate may also work, but be careful in the summer heat, as it melts and can make a sticky mess! Hazelnut spread may work as a substitute for peanut butter, and often contains chocolate too.
If certain baits aren’t working, don’t be afraid to experiment. Why not let the rodents tell you what they prefer? To find out which foods the rodents like, lay a little feast for them overnight, small piles of different foods without any traps, and observe in the morning what was eaten the most!
Tip 3 – Prevent Bait Theft from Traps
Rats and mice are intelligent creatures and can work out ways of stealing the baits from traps without tripping them.
To prevent the removal of the bait from traps, use a thin piece of wire of any sort as a bait-retention wire to hold the bait in place.
NOTE: Always bait traps first, then set them to avoid catching your fingers!
To attach a bait-retention wire to a rat or mouse snap trap:
- Thread the wire through the trigger (trip) that holds the bait
- Attach bait to the trigger (trip), then gently twist the wire around it to hold it securely.
Steel wire trap have a different trigger mechanism, so the bait retention wire can be looped around the cross-bar that holds the spring in place.
On these traps, push the bait onto the two wire prongs of the trigger mechanism to hold it in place, then twist the bait-retention wire around the bait to secure it in place.
Any attempts by a rat or mouse to snatch the bait from the trap will be prevented by the bait retention wire, and the shock of the sudden pull may cause the trap to trigger.
Tip 4 – Set Trap Triggers Lightly
To increase the effectiveness of the traps, set the triggers lightly, so they will spring with the lightest touch.
A trap with a ‘hair trigger’ will trip easily and prevent rats and mice from stealing the bait or gently nobbling away at it.
The way to set the trigger lightly is by pushing the latch (retainer bar or hold-down bar) so it barely pokes through the trigger (trip) bar that holds the bait.
The more the latch pokes through the bait, the further the rodent has to push the trigger down when taking the bait in order to trip the trap.
On steel wire traps, the springs are quite strong, so the traps may take a bit more force to set them off. Overcome this by sitting the wire loop of the trigger as close as possible to the end of the latch bar so it takes very little movement to release the latch and trip the trap.
Tip 5 – Use Many Correctly Placed Traps at Once
Using more traps increase the chances of catching more rodents, so use as many traps as are available to make the trapping period short and reduce rodent numbers even faster.
Maximise the number of traps that are operational by removing captured rodents and resetting/rebaiting traps daily, until there are no more rodents left. Keep a few baited traps out after eliminating a rodent problem, as new rodents may emerge in time.
When setting up traps for rats and mice, it’s important to:
- Set up the traps in the correct locations where the rats and mice are.
- Use the correct distance between traps based on how far rats and mice range.
- Position the traps correctly relative to the surroundings for maximum effectiveness.
Where To Set Rat and Mouse Traps
Rats and mice are creatures of habit, they take the same routes when leaving their nests to travel to sources of food and water. These pathways that they frequently travel along are referred to as rat and mouse runways.
Runways usually follow straight paths along natural or manmade edges and lines. Since rats and mice have poor vision (but a very keen sense of hearing, smell and taste), they’re exceptionally cautious, and tend to move from place to place along the cover of walls, structures or other objects, away from wide-open areas where they’re more vulnerable to predators.
- Indoor runways may follow along the baseboards of interior walls, over attic roof beams, indoor pipe runs and around or behind large objects such as storage boxes and equipment.
- Outdoor runways may follow building foundations, deck and sill ledges, electrical wires and conduits, fence rails, pipes, sewer lines, tree branches and wall tops.
It’s best to place traps along these runways, where rats and mice are more likely to encounter the traps.
How Far Apart Should Rat and Mouse Traps Be Placed?
The distance between traps is dependent on how far the rodents range from their nests. If they only travel shorter distances, then traps need to be placed closer together, otherwise traps placed further out may be of no use.
Mice will only travel around 3-10m (10–30′) from their harborages (place of shelter, refuge or dwelling), while rats may travel 30-50m (100–150′) or more.
This means that traps need to be placed closer to each other trap mice as compared to rats.
- For mice, place two or more traps around 2m (6′) apart, and no more that 3m (10′) apart along their rodent runs.
- For rats, place two or more traps around 4-5m (6′) apart along their rodent runs.
How Should Traps Be Positioned?
Traps need to be positioned in a way so that rodents can be caught whichever direction they approach the trap when running along a wall, structure or object.
1. Single Trap at Right Angle to Wall
Baited traps should be set a right angle to walls or edges that are used as rat and mouse runways, with the bait facing inwards towards a wall or object.
Having the bait facing the wall leaves less room for a rat or mouse to maneuver between the trap’s spring-loaded swinging striker that it will try to avoid, and the wall which limits its movement and escape path.
2. Double Traps at Right Angle to Wall
We can also place two baited traps side by side, set a right angle to walls or edges that are used as rat and mouse runways, with the bait facing inwards towards a wall or object.
This has all the same benefits as the similar single-trap setup, but with two traps, two mice can be caught at the same location, which is an advantage in areas with lots of rodent activity. Also, if one trap is tripped but a rodent is not caught, the second trap will still be active in the area.
3. Double Traps Parallel to Wall
Placing traps parallel to the wall, and back-to-back, with the baits facing outwards permits rodents to be caught coming from either direction along a runway.
With similar advantages to the ‘Double Traps at Right Angle to Wall’ layout, this setup is much closer to the wall, which may help keep traps from getting accidentally kicked by human foot traffic.
This back-to-back arrangement, when used in open areas, leaves much more room for evasive rodent maneuvers if they try snatching the bait really quickly than a side-to-side arrangement, but is an excellent option when used in narrow spaces behind or between objects, where evasive space is limited.
4. Traps Placed in Confined or Narrow Spaces
Rats and mice have very fast reflexes and will always try to quickly swing out to the side of the trap and away from the trap’s swinging striker!
What happens if they have no room to swing out to the sides for an evasive maneuver? Their only option is to back up, and moving in reverse is the slowest and most awkward direction of movement for most if not all animals.
By placing traps, either single or double, between objects, or in narrow spaces between walls/fences and other objects, the success rate of traps can be greatly increased. Just make sure that the rodents can’t reach over the objects blocking one of the sides of the trap – the brick used in the photo is way too low for rats, but if the bricks were stacked two or three brick high, that would be more effective.
Make sure the baited end of the trap is pushed back far enough between obstacles to limit the option of sideways movement for rodents as much as possible. To entice rodents into these narrow spaces, it helps to place some bait in front of the trap as a free feed to lure them closer to the trap itself.
Tip 6 – Use the Three-Day Technique to Catch Even the Most Cautious Rats and Mice!
Animals notice changes in their surroundings, it’s an important survival instinct. Placing a trap in areas where there is rodent activity essentially introduces a new, unknown object in their environment.
Rats and mice display different behaviours around any new objects.
- Rats are very cautious and will actively avoid new objects in their path. It may take them a few days to a week before they feel comfortable enough to approach a trap. Patience is important with rats!
- Mice are curious by nature and will normally approach traps on the first night that they’re deployed. If traps aren’t catching mouse in the first few nights, it’s a likely indication that the traps are in the wrong location.
The Three-Day Technique for Catching Rats
Here’s an explanation of my ‘Three-Day Technique’ which works great on the most cautious and elusive of rats and increases the catch count drastically every time.
Step 1 – The Feeding Phase
To help rats overcome trap shyness, and give them a false sense of security, place baited but unset traps along rat runways, and leave them in place for several days for the rodents to familiarise themselves with the new object, enjoy the free food, and become less cautious.
Placing a few loose pieces of bait around the traps can make them even more inviting. The rodents should be able to feed without any risk of harm at this point. After around two days, the rats should be confidently eating the bait off the trap and around it.
Step 2 – The Finale
Once the rats are happily feeding from the trap, they’ll naturally come back for more. This is the point where one small, but critical change is made.
This time round, which is usually on the third day, the bait is replaced on the trap, and some more loose pieces of bait are placed around the trap, as was previously done – but the trap is also now armed and set. The next visit the rat makes will be the last.
Tip 7 – Setting Runway Traps
Traps don’t need to be baited to work! Runway traps are traps set along runways (paths that rats routinely take), to take advantage of areas where rats travel, that can catch rats when they accidentally bump into the trigger.
How to Make Runway Traps for Rats
Runway traps can be purchased with large trip pedals, but regular snap traps need to be modified to make it easier to trigger them when rats run across them.
To make runway traps from regular snap traps, enlarge the trigger to turn it into a treadle (a flat lever to tread on) by attaching a piece of cardboard, plastic, wire mesh, or screening onto the trigger lever with a small piece of wire or string.
Shown below is a close-up view of the plastic treadle attached to the trigger. Attaching the piece of plastic as a treadle or trip lever extends the length of the original trigger. Whenever we double the long end of a lever, such as the trap trigger, we double the mechanical advantage, so it will only take half as much force to trigger if pressed on the far end.
What this means is that runway traps are much easier to trigger than the same trap in its regular form and can be tripped with a very light touch.
Where to Place Runway Traps for Rats
Runway traps should be placed along likely runways such as along walls, behind furniture, and near holes where rats may be nesting.
To fasten traps to pipes, beams or rafters that are used as runways by rats, use rubber bands or hose clamps. Wooden or steel wire traps can be nailed to rafters and beams.
Place traps at right angles to walls or along narrow runways., and only set traps where they will not present any risk to children or pets.
Since there is no bait to go stale, it’s possible to ‘set and forget’ many runway traps, maximising the chances of success.
Are Live Catch Traps a Better Option?
Cage or bucket-type live catch traps are available to capture mice and rats alive. Multiple-capture live traps are also available that can catch rodents continually without needing to be reset. When using these kinds of traps, it’s important to check them frequently as mice or rats left there for a long time will eat each other when they begin starving, and rats will normally eat mice if they find them.
Live traps aren’t a preferred option, because trapped rodents must be:
- Humanely euthanised, which is very unpleasant thing to do when faced with the task.
- Released outdoors somewhere else, which isn’t recommended, as they’re not native animals, and can harm native wildlife and ecosystems, as well as cause health concerns to people, pets, and other domestic animals.
Are There Any Safe and Environmentally Friendly Rat and Mouse Baiting Options?
If there are reasons why traps can’t be used, and it’s necessary to use a bait, but poisonous commercial rodent baits present an unacceptable risk to pets or native wildlife, then there’s one more option.
It’s quite easy to make an environmentally safe, home-made rat and mouse bait that uses bicarbonate of soda (baking soda). This exploits a unique feature of rat and mouse biology, their inability to burp or vomit, to create an effective rodent control. For further details and instructions, see article – How to Make Safe and Effective Rat and Mouse Baits Using Baking Soda
More articles on Garden Pests, Diseases and Problems
- IPM Handout for Family Child Care Homes, INTEGRATED PEST MANAGEMENT: RATS AND MICE, California Childcare Health Program, University of California, San Francisco School of Nursing
- Rat and Mouse Control – ENY-224, UF/IFAS Extension Service, University of Florida, P. G. Koehler and W. H. Kern Jr.
- University of California, Statewide Integrated Pest Management Program, How to Manage Pests – Pests of Homes, Structures, People, and Pets – House Mouse, Revised 10/11
- Prevention and Control of Wildlife Damage. Editors, Scott E. Hygnstrom, Robert M. Timm, Gary E. Larson. 1994. University of Nebraska-Lincoln. 2 vols., House Mice
- Arakawa H, Blanchard DC, Arakawa K, Dunlap C, Blanchard RJ. Scent marking behavior as an odorant communication in mice. Neurosci Biobehav Rev. 2008 Sep;32(7):1236-48. doi: 10.1016/j.neubiorev.2008.05.012. Epub 2008 May 15. PMID: 18565582; PMCID: PMC2577770.
- Dagg, Joachim. (2011). Exploring Mouse Trap History. Evolution Education and Outreach. 4. 397-414. 10.1007/s12052-011-0315-8.
- National Pesticide Information Centre, Rodenticides Topic Fact Sheet, http://npic.orst.edu/factsheets/rodenticides.html