Super Rats and Giant Rats – Fact or Fiction?

pest control - super rats and giant rats

Over the past couple of years, the news has been filled with stories of people spotting giant rats in their homes and businesses as well as tales of indestructible super rats. With all this media attention around these new “breeds” of rodents, I thought it was about time some truth was shon on these urban legends.

Click here to learn about Super Rats

Click here to learn about Giant Rats


Super Rats

super rats infographic

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The whole notion of super rats was developed through an idea that some species of rat have developed a resistance to the bait laid out by both homeowners and professional pest controllers.

When discussing the idea of a new super breed of immortal rats showing resistance to rodent bait we first need to understand what resistance actually means.

Resistance is Not…

Bait Shyness

Bait shyness relates to a rodent‘s natural instinct to be cautious of the new and unknown. This is not regarded as a resistance as once rodents overcome the shyness they will soon feast on the bait.

This has commonly been mistaken as a resistance as previous models of bait being were quick acting. This means that they relied on the rodent taking the bait as soon as it had been laid down. When the rats finally succumbed to accepting the bait it was usually useless and had no effect on the rodent in question.

Poor Palatability

Poor palatability often gets mistaken for resistance. Sometimes rats just simply dislike the taste of the bait laid down and, therefore, do not accept it. Although rats aren’t really picky when it comes to food, there are some instances where some substances just aren’t to their liking.

Did You Know unlike us, rats can’t vomit? Because of this, they tend to lick new food/bait before consuming it in order to test if it is safe to eat.


Rats are very hesitant creatures, they will often feed on the same, trusted, sources and only search for new places if they have to. On top of this rats learn food preference from others, so will eat the same food, from the same places as each other.

It is well known that rats suffer from a fear new things (neophobia). When it comes to baiting this can be an issue when a new bait or bait boxes are introduced. If rats avoid the new product entirely, it makes this rodent control method completely ineffective.

Excuse for Poor Pest Control Practices

In some instances where rodent resistance has been reported, it is actually a case of poor pest control practices.

Factors leading to ineffective rodent control:

  • Not successfully discovering all parts of an infestation
  • Not laying down a sufficient amount of bait
  • Not laying down bait in every infested area
  • Not waiting long enough for rodents to start feeding
  • Not waiting long enough for bait to become effective
  • Not replenishing bait often enough
  • Not doing everything possible to ensure a re-infestation doesn’t happen.

All these factors can be the result of a failed pest control service, and not because of a rat developing a resistance to anticoagulants (bait).

Resistance is…


A rodent’s resistance to pest control techniques comes down to genetics. Resistance is based on a selection of genetic mutations to which, after all, the necessary and correct pest control services are carried out, the rodent in question has a reduced sensitivity to bait due to their genetics.

Just like antibiotics, a rodents resistance to bait has been increased through poor pest control practices such as the continuous use of weaker baits as well as under baiting.

All these factors combined makes rodents partially susceptible to the bait.

Do Super Rats Exist?

To answer it simply, yes. But not in the sense that these ‘super rats’ are unstoppable.

It mainly means that there is a handful of rats which have accumulated a resistance to certain baits.

However it is worth noting that there is no such thing as an ideal rodent bait, this mainly due to the necessary factors that need to be complied to.

In cases where the rodents occupying a property are resisting the regular forms of rat control, other techniques such as proofing have to be introduced.


Giant Rats

Giant rats infographic

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You may have read news stories online such as this one about people finding giant rats in their homes. But are these stories just urban myths or do giant rats actually exist?

Urban Rats

When people talk about giant rats, they are actually talking about urban rats. Urban rats, unsurprisingly refer to rats living in urban environments such as cities and towns. Compared to rats found in rural areas (parkland rats), urban rats tend to be a lot bigger in size.

A study conducted in Baltimore USA between 1984 and 1986 saw 850 rats captured, 167 caught in parklands and 683 were collected in urban areas. The urban rats were significantly heavier than those captured in parklands and the males were much larger than the females in both habitats.

How Can Urban Rats Get So Big?

According to the British Pest Control Association (BPCA), diet is key to larger rats. Rats living in urban areas such as large towns and cities have unlimited access to food. This results in a higher reproduction rate and a longer life span.

Rats living in urban environments tend to grow more rapidly than those in rural areas, which has an increasing effect on their survival. Urban rats continue to gain weight as they age, which allows them to reach a higher body mass.

One of the main contributors to an increase in larger sized rats is a combination of food and milder weather. Urban areas are filled with shops, cafes, and restaurants, all of which provide a high supply of food not only within these premises but also the food they dispose of at the end of the day.

During the colder seasons, the growth rate of urban rats is still quite high. This is mainly down to food waste. The majority of the food wasted in urban areas are those high and sugars and fats. This is the main, stable, source of food for urban rats throughout the year, and the colder weather slows down the rate of decay. This allows said food to be available for longer, providing rodents with a steady flow of feed which is easily, and constantly accessible.

Do Giant Rats Exist?

In a way, yes, but this is not a new breed of rodent. Essentially what you have is a species of rat which come in a range of different sizes – just like humans. For example, you could have a fully grown adult who is only 5ft whilst another could be well over 6ft. Giant rats are simply rats at the extreme end of the size spectrum, rather than a new breed entirely.

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