Get rid of rats and keep them from coming back

Rat Infestations: Small and Large Scale Problems

You may be like many people, for whom the idea of having a rat anywhere around their home is enough to cause alarm, not least because of worrying about how to get rid of it. It’s unpleasant, but just imagine the concern if instead of dealing with a single rat, there was a whole colony of rats that needed to be removed.

Small Scale Infestations

This infestation of rats, if it is not dealt with, can very quickly escalate from a being just a nuisance to an out of control and serious health hazard, requiring professional expertise to eradicate the colony of rats.

Now before you go running off to call your local exterminator, it would pay to understand just how an infestation of rats happens, how you can identify it, and most important of all, how you can prevent it from happening in the first place.

When is it a bigger problem than just a stray rat?

The first thing you want to be able to do is to recognize whether the unwanted guest in your property is a single stray rat, who is just passing through, or an infestation where the rats have already started to multiply. To do this you need to look for clues which will tell you which it is.

Whenever rats take up residence you will start to both hear and see the signs. If you suddenly hear scratching noises coming from behind walls and under floorboards then you can be pretty sure at least one rat is moving about. If these noises can be heard through the night, and from more than one location, then the likelihood is that a lot more than one rat is moving about.

Here is a GREAT video by Animal Planet that walks you through a homeowner’s real-life situation and how she finally solved the problem.

Another obvious sign is rat droppings appearing in specific locations around the house. A single rat can expel up to 40 droppings per night, so if what you are seeing is a lot higher than that number then you could have an infestation.

Seeing lots of tracks or runways around your home will tell you that there are rats making their way around your property. These tracks will not only be footprints, but will also contain smudging, droppings, and urine stains. They will tend to lead to where the rats are accessing food or hidden areas where they have built their nests.

Look for nests in areas of your property such as attics, cellars, lofts, and even within cavity walls. The items rats use for these nests will include paper, loft insulation, and other soft materials. One thing to bear in mind is all these runways, holes, burrows, and nests will have resulted in varying degrees of damage to your property which includes discolored paint and scratch marks at one end of the scale all the way up to fire risks from electrical cables being chewed through or even structural damage to foundations.

One of the most telling clues which can help us determine if we have a problem is the fact that rats are nocturnal creatures. When there is only one or just a few of them, their nightly feeding trips will be enough to satisfy them all. However, if your house is infested with rats, many of them will not have been able to eat during the night so they will venture out during the day to look for food. Seeing rats running around during the day is a tell-tale sign of infestation.

The question we must now ask is why these infestations occur, and more importantly how do you stop them? Notwithstanding that your home provides them with warm shelter and sources of food, rat infestations occur mainly because of the nature of their breeding and reproduction.

A female rat becomes sexually mature at just four weeks of age and if she becomes pregnant the gestation time of her young is a mere three to four weeks. An average litter is between six and 12 pups and a female can produce upwards of 10 litters a year. To save you doing the math, these numbers all add up to the potential of a single female potentially producing at least 120 babies in a year.

But that is not the end of it because those babies which are female can begin producing young of their own very quickly and so the population grows further. It’s not hard to see how all this can add up to a lot of rats, and a serious infestation that needs to be dealt with.


Apart from the inconvenience and discomfort of knowing there are rats infesting your home, a more serious element of this problem is the fact that rats carry many health risks for humans. Some of these include very serious diseases which, in extreme cases, could be fatal especially to the elderly and those already weakened by another illness.

Some of the diseases which rats can cause do not all stem from being bitten or scratched by them, albeit both are to be avoided. Many airborne viruses will result from rat saliva, urine, and as you breathe in these viruses, they can induce leptospirosis, which can create serious liver or kidney damage.

Salmonella is another disease that is created by breathing in air containing viruses that rats are responsible for. Salmonella can induce severe fever, diarrhea, and pains around your abdominal area.

Rats also attract fleas that feed on their blood, and if that same flea then bites a human it can pass on tularemia. This can generate skin ulcers, as well as severe exhaustion and fever.

If you are unfortunate enough to be bitten or scratched by a rat, the aptly named rat-bite fever is an illness that can occur. This has a whole list of symptoms, with the most common being skin ulcers, vomiting, and fever. In some cases of rat-bite fever, lymph nodes can swell to fight the infection, and cause pain throughout your body.

What causes infestations and how to prevent them?

Rather than having to deal with any health risks, damage to your property, or just the absolute distress that an infestation of rats can cause, the best action is to prevent them from ever happening in the first place. This is often a lot easier said than done, but if you follow some simple steps and take the right precautions, your home should remain free from rats.

The first way to keep rats away is to remove one of the primary attractions that your home has for them and stop it from becoming a source of food. Rats will feast on just about anything so every step you can take to stop scraps and even crumbs of food being easily available to a rat will help.

Areas around your trash cans are the most obvious place to start, and anytime you are throwing away food waste make sure all of it goes into the can. More than that, ensure the lid of the trash is securely in place.

If you have any pets which you feed outdoors, you may want to reconsider that, or at least make sure once they have eaten you clear away any mess they may have made.

Wherever food is prepared or eaten should always be cleaned thoroughly after use, whether this is indoors or outdoors if you perhaps have a barbecue on your patio. Food storage containers should be kept tightly sealed and any spillages wiped away as soon as possible.

While rats need food to survive, they also require water to survive too, and you can take steps to eliminate this if you can. Outdoor taps, hoses, and pipes should all be checked for leaks and turned off fully after use. You might also want to remove any bird baths or pet water bowls from outside too, as these make great sources of water for rats.

Having denied the rats a ready source of food and water you can now stop them entering your property. Look for cracks or holes on the exterior of your home, including walls, window sills, lintels, and even external drainage pipes. Materials such as steel wool are ideal for these tasks.

The last task is to make sure there are no obvious places around your property that will make an ideal home for a rat. It’s also an ideal opportunity to tidy away or even get rid of any rubbish and clutter that has accumulated in your attic or cellar. Other storage areas such as a garage or garden shed should also be tidied out as well.

A spot of gardening such as trimming overhanging tree branches, cutting the grass, and tidying up shrubs and vegetation will make your premises less appealing to any rat who is thinking of moving in.

Infestations in rental homes: Is the landlord responsible?

Unfortunately, you could be in the situation where the problem has already ready happened so rather than prevention you are now thinking about a cure. If the property is your own, then you are the person who is going to have to make the decision of how you want to deal with it. However, if you live in a rental property, the question must be asked whether or not your landlord is responsible, and if they are, how they are going act upon that?

Whilst we cannot address every tenancy scenario, the general position is that any reputable landlord must make their property habitable, and as result, an infestation of rats is an obvious situation where they are responsible for dealing with it.

Of course, one should always check a tenancy agreement prior to signing, but most standard agreements will put the onus on them to maintain the property in terms of rodent control. Should they fail to do so, they can face large fines, and there are even examples of lawsuits being granted against landlords who fail to meet this requirement.

There will obviously be some onus on the tenant too, in terms of keeping the property clean, so do not expect a landlord to foot the bill if the sink is always full of dirty dishes, and the lounge floor covered with half-full takeaway food containers. Other matters such as taking the trash out regularly, and even reporting any faults or leaks, are also down to the tenant.

If a landlord employs a pest controller they will receive feedback from them on the cause of the infestation. If it is obvious that the tenant has acted in ways that have directly lead to the rats infesting the property, the landlord may ask for a partial or even full contribution towards the costs of the extermination.

While landlords are likely to use professional pest controllers to deal with a rat infestation, as a property owner you may choose to deal with it yourself. While there are many ways you can do so, such as traps, and poisons, if you are trying to deal with a whole colony of rats, it may take some time, and might not always eradicate every single rat.

Infestation solutions

Remember the numbers from earlier regarding how many rats can be born within a colony, and you may find yourself trying to get rid of hundreds or even thousands of them. Therefore, it is recommended that a professional pest control company should be approached to deal with rat infestations.

Before they even come up with a solution, a pest control expert will be able to identify the type of rat that has infested your home. This will most likely either be the Roof Rat, or the Norway Rat. Based on this identification the action they may first recommend is thorough sanitation so that no further rats are attracted to your property.

To eliminate the rats that already exist, a pest controller will have a combination of solutions such as the use of baited traps and poisons including rodenticide. They will set up a number of these traps throughout your property, especially in locations where there’s clear evidence of rat activity. Variations will include the use of tamper-resistant traps if there are children or pets living in the property.

Depending on the success of their initial trap set-up, an exterminator can arrange to re-visit your property to follow up and may adjust several factors such as the position of the traps, the bait they are using, or even alter the poison type. Each adjustment they make should improve the success of the extermination.

Clean up afterward

Once the extermination is complete and all the rats eliminated, any decent pest controller will agree to clean up afterward. This will include removing all the dead rats and ensuring that any of their nests are destroyed. The cleanup should also cover those areas around the trap positions to make sure no poison or bait is left behind.

Large Scale Infestations

We have spoken so far about domestic rat infestations which you may be surprised to know are considered ‘small-scale’ infestations. It might seem odd that the several hundred rats that invaded your home is considered a small infestation but think about an infestation of rats that happens on a city scale.

Cities with the worst infestation problems

There are many cities around the world that suffer from rat infestations that seem almost biblical. New York is estimated to have one rat for every four people who live there, so with a human population of over 8.5 million, you won’t need a calculator to realize that means there are over 2 million rats living in the Big Apple.

Other cities in the USA who suffer large rat infestations include Philadelphia, Chicago, Dallas, Los Angles, and Washington DC who are all in the top 10 of the rat league. And it is not just cities in the USA which suffer from a rat infestation. London is estimated to have upwards of 7 million rats, and recent floods in France have seen the rat population in Paris increase to around 4 million.

How cities are dealing with infestations

Of course, the way in which cities deal with rat infestations is a lot different not only in terms of scale but also in the methodology used than would be the case with small-scale domestic ones. The idea of setting rat traps on every street corner might amuse, but it certainly won’t deal with the rats.

One thing which cities have put ever-increasing resources into is research on the rat population, to establish numbers, breeding patterns, and movements of rat colonies throughout the city. This information makes the decisions on how to treat the problem more informed, and more effective.

Preventative measures such as rodent-proof trash cans and waste receptacles for domestic and commercial properties is one advancement. The use of devices that emit ultra-high-frequency sounds is also another deterrent for rats.

One aspect of dealing with rats is research showing that the way to eliminate them in one part of the city may be completely different than in other parts. Based on this data, the most appropriate baiting and poisons are utilized where they have been shown to work well.

Another recent method that was introduced was the use of dry ice. This is placed into rat burrows and as the dry ice melts, carbon dioxide is released which suffocates the rodents. There have also been trials of a compound that causes females rats to prematurely enter menopause thus preventing them from breeding and giving birth to more offspring.

Islands that have/had major infestation battles

While cities seem to have their hands full looking for ways to eliminate rats, there are several locations around the world that might be the last place you’d think would need to deal with a rat problem. In particular, there are many islands that have had their fair share of rat infestations as well as places where you’d wouldn’t expect rats would want to call home.

A remote and idyllic atoll in the South Pacific called Henderson saw its rat population rise from a few hundred to over 100,000 and the irony is that the island had just been scattered with 80 tons of cereal pellets designed to poison the rat population. Unfortunately, heavy rainfall at the time of the airdrop saw the island’s vegetation grow at an incredible rate to the extent that the rats had no need to eat the poisoned cereal pellets and thrived.

Another island that is situated within Alaska’s Aleutian Islands was even given the name ‘Rat Island’ such as the size of the rat population that had existed there since the 18th century. The decision was taken in 2007 to eradicate the rats not least because of the adverse effect they were having on the island’s other wildlife. In 2009 the island was airdropped with brodifacoum rat poison for over a week which completely wiped out the rat population. This was not without its problems though as other animals and wildlife were killed too.

The worst infestation ever

The worst ever infestation of rats occurs every 48 years in the Indian regions of Mizoram and Manipur, which are located in the Northeast of the country. The rats thrive due to the phenomenon of a bamboo plant flowering across vast areas and they then feast upon the seeds that are created. Such is the increase in the rat population that it is known as a ‘rat flood’ and the locals call it Mauzum which translates to ‘bamboo death’, and it is an apt name.

Once the rats have finished gorging on the bamboo seeds they then satisfy their hunger by eating crops. This means local farmers are left with neither a livelihood, nor sustenance, and thus famine occurs in the area. The number of rats that cause these issues is estimated to be several million, and the devastation that they cause makes many of the city infestations we mentioned previously seem like minor irritations.

Long Term Forecast

As cities around the world expand to even greater sizes due to population growth, as industrialization increases exponentially in many countries, including China, and with growing evidence of global warming, we must be concerned that rat infestation will continue to increase and whether it can ever be completely controlled.

It may shock you to know that the worldwide rat population is 7 billion, which is just about one rat for every man, woman, and child on our planet. There is an undeniable fact that as the human population grows so does the rat population, but it is the rate of growth of the rat population that is alarming.

In 2001 the estimated rat population was 4 billion, and at the time humans numbered just over 6 billion. Given that the two populations are almost equal now it doesn’t take a math genius to work out which of the two is rising at a much greater rate. As such it appears that rat infestations are going to be here for some time to come, and if their population growth can’t be curtailed, we will soon find that rats outnumber humans in the not too distant future.

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