They are voracious nibblers and gnawers, promiscuous spreaders of disease and a right nuisance. Their population in the UK is rising, with pest controllers lobbying for the use of more deadly poisons, but can we ever tackle the rat menace?
We live cheek by furry jowl with rats.
And we don't like it. Rats are unhygienic, they spread disease and they spoil food. And in the UK at least, it seems their population is rising.
According to the National Pest Technicians Association's annual rodent survey, callouts to brown rat infestations rose 15% between 2006/7 and 2007/8. It suggests that numbers must also be rising significantly.
There are numerous factors blamed for this burgeoning population. We have had mild winters in much of the UK in recent years, the rubbish we put out is changing, and many people have compost heaps. Even our love of decking provides happy habitat for the rat.
Rats also thrive on food put out on bird tables and are happy to scavenge among the cornucopia of polystyrene fast food containers littering our streets.
If we encounter a rat in our house, garden or street, our first port of call is usually the council. Pest controllers come out and they put down anticoagulant poison. Within a fortnight any rats who have eaten enough bait die.
But those in the rat-catching business fear we are seeing the rise of super-rat, resistant to traditional anticoagulants and they want the rules changed to allow the use of more powerful poisons.
Some in the industry blame householders trying to do their own rat poisoning and getting the doses wrong.
"Rodents aren't given sufficient bait. It's sub-lethal dosing. If you constantly feed them small doses you build up an immunity," says Oliver Madge, chief executive of the British Pest Control Association.
"Rats can produce every six weeks and they can have six-to-eight offspring."
So it doesn't take many years for resistance to start to take hold.
The industry wants the government to allow wider use of brodifacoum and flocoumafen, deadlier poisons - or rodenticides - that are not permitted to be used outside.
Of course, resistance to poison is not the only thing causing the rat menace.
Some newspapers have seized on rising rat numbers as evidence of the foolishness of fortnightly waste collection. And an NPTA survey of rat problems in south-west England found 28% could be attributed to bird feeding.
Decreased use of poison in sewers has also been blamed.
But the answer may be even simpler than that.
"Rats are opportunistic animals. They have survived because they have worked out how to live in close association with man," says Dr Gai Murphy, urban pest researcher at the University of Salford.
Thus it is perhaps not surprising that as our numbers grow, and the amount of food and waste we produce rises, so rat numbers grow.
"Numbers are going up. They go up in response to food and harbourage, as urbanisation and agriculture intensifies," says Dr Steve Belmain, an ecologist and expert on small mammals at the University of Greenwich.
"Littering and leaving food out for the ducks, all those sorts of urban behaviours all encourage their population to expand."
And some might be worried by the authorities' response. No government department takes responsibility for monitoring national rat numbers. It is all done at local authority level, with no national collation of figures. In short, there is no national rat strategy - no rat tsar.
And yet there is a danger from the rise of the rat.
Many will have heard of Weil's Disease, also known as leptospirosis. But that isn't all.
"Rats have notoriously weak bladders. Any surface they have walked on will have a trail of urine on it," says Dr Murphy.
"A lot of it is about mechanical [spreading of disease]. They are feeding on foodstuffs that have gone off, with salmonella and listeria and they deposit these bugs as they walk."
You can scrupulously clean everything in your kitchen, but if a rat rummages through some discarded chicken in your next door neighbour's bins and then walks over the clean pans in your cupboards, you could be in trouble.
And rats have the capability to cause electrical fires and other types of damage.
"It is a big problem in hospitals with wiring, getting into the walls and damaging expensive equipment," says Dr Belmain.
And yet, as Dr Murphy notes, many local authorities are now charging to deal with rat infestations.
"Sometimes councils see pest control services as a way of generating revenue. They start by charging, demand goes down and they review the service and say nobody seems to want it. Then they close it."
This means the loss of valuable knowledge.
And part of the problem is cultural. The brown rat - Rattus norvegicus - is a disgusting animal. Even its name, the "Norwegian rat" is an inaccurate attempt to emphasise the foreignness of the creature.
References to "rat" as an insult go back to at least the 16th Century, the Oxford English Dictionary says. Other uses include "to smell a rat", "like rats deserting a sinking ship", "rat" as a term for the smallest or inferior of a group, and "rat" as someone who informs or sneaks on a colleague.
It's perhaps understandable that some people in power would prefer to play down the issue of rats.
"They don't really want to talk with rat [experts]. People want to sweep it under the carpet," says Dr Belmain.
Just two months ago, newspapers reported that Flamborough in north Yorkshire was suffering a plague of rats. Now, with the infestation suppressed, the residents are not keen to reminisce about their rodent problem. It keeps the tourists away, explains one local.
And perhaps that's the problem. We're disgusted by rats but we don't quite have the motivation to tackle them at a national level.
Below is a selection of your comments.
Rats have never had it so good. Look at the rubbish on the pavements, leftover burgers, chips etc. If there were more bins they'd be less for rats to eat. I can walk for over a mile where I live and not see a bin. There should be one at every bus stop and one in between. Community police should be able to issue on-the-spot fines for littering, and concerns like McDonald's should contribute to the cost of clearing litter up.
Tina Pointing, Manchester
Our local council has a scheme where waste food is collected in a plastic box with a lid, therefore the food is not throw in the rubbish bags which causes rats to tear the bags open. The rubbish bags are also put into big wheelie bins. This has seen a massive decrease in rats in our area. Don't blame the rats, they also need to eat like humans. It's the humans that encourage rat infestation by not putting rubbish in the bin and being lazy by throwing it on the streets instead.
KS, Ealing, London
Rats are not dirty but they do thrive on the waste left by dirty people.
Rats may keep themselves clean but they leave a filthy, smelly mess behind them. They rummage through the sheds, knock containers off shelves, chew anything that's plastic or cardboard and leave a sticky residue all over tools, etc. I find I cannot store anything outside. They constantly chew through the live freezer cables and I've spent a small fortune in replacing/repairing cables, running them through PVC pipes (thicker than normal conduits) and the expense of wasted defrosted food. They chew holes through wooden or plastic sheds and chewed their way into a 10kg bucket of rat poison and ate it all in one or two sittings. Obviously not intelligent enough to read the large label marked RAT POISON. At considerable expense I had a brick rubbish store built outside my house but they chewed through the heavy marine ply lid to get to the rubbish bags stored inside. Incidentally, my bags never contain foodstuff as our small amount of waste goes to the dogs. I am waging a one-woman war against these creatures. It's me or them. Rats are a real problem which the authorities are not taking seriously enough.
Marie Severn-Kumar, Ely, Cambridgeshire
I have kept rats as pets, intelligent and vey clever. The suggestion from the Peta website is as pathetic as they are. All you are doing is making your problem someone else's. Rats need to be controlled wherever found because of the danger they pose to us and our wildlife. I don't believe in poison but trapping and the use of dogs is effective. As for trapped rats taking one minute to die - this means you are not doing it right or you aren't using the correct equipment.
My two cats died last year and this spring I noticed a rat in my garden, after the bird food in the feeders hanging in the tree. I live in the countryside and am aware that there are rats around, always have been, but not coming into the garden. I think my cats kept them out. Very soon there were half a dozen babies running about. I have now got another cat from the Cat's Protection League and hope that this will scare them away as I don't particularly want to kill or have them killed. And I have changed my way of feeding the birds. I put only a little in the feeders rather than fill them up, as I would still like to have birds (and the red squirrels we still have) come into the garden.
Anne Halket, Montrose, Scotland
I would like to refute a very important point that you made: Rats are not disgusting animals. They spend most of their days cleaning themselves meticulously, washing their paws and using them to clean their bodies. Rats do not cause disease - unlike marmots which actually create the "bubonic plague" bacteria in their bodies. Any diseases they spread are those present in their environments that they pick up, no different than a stray dog or cat. Actually, unlike cat and dogs, brown rats themselves cannot contract the plague - even if bitten by fleas carrying the bacteria.
They are very intelligent animals that are merely taking advantage of the unclean environment that we humans create.
Anyone who keeps a pet rat will tell you they make great loving pets. They are very clean and intelligent animals. Its filthy human hygiene we should do more about. Not leaving food takeaways in the streets for starters. Why else do wild animals (and not just rats, but foxes et al) come so close to humans other than a free lunch?
Not everyone is "disgusted by rats", as you say. I have kept one as a pet and my brother has two. They happen to be extremely intelligent and very clean animals. And who exactly are you to say that they are a "disgusting animal". How exactly are they more a "disgusting nuisance" than a human being? Humans regularly throw food and rubbish to the floor; relieve themselves and vomit on the streets every night of the week and freely pass diseases amongst themselves without the help of any rat. An increase in rats is simply the consequence of our own filthy habits. We are the ones that are overpopulating and making the mess here.
We have had a problem with rats in our cavity walls for almost 8 months! It's very stressful and upsetting. Our local council did send pest control to us free of charge but they did not want to help us find out how they were getting in and each visit only lasted a max of 10 mins. We got fed up and are now paying out for a private company to help us which seems to be getting us closer to the root cause and their visits last 1 hour! Note the difference. I'm outraged at the lack of interest, action and help the council has given us.
It is historical fact that it was black rats that carried the fleas that spread the plague in the middle ages. The brown rat's dominance has helped to curtail black rat numbers. I for one don't want to see a resurgence.
Mike Manship, Swindon, UK
I found a way of keeping rats away on the PETA website. A mixture of Cayenne pepper, horseradish, garlic and salad oil. Leave to steep and then spray around bins etc., it works.
Helen Faulkes, Solihull
Having moved from the city I had rats in my roof (a mid terrace) when I moved to a small town in Wales. I tried to raise the issue with neighbours, but they refused to acknowledge there was a problem (worried about the effect it might have if others found out or didn't see it as a problem). 15-20 rats later over a couple of years - caught in traps in the loft - I just sold up. The final straw came when I caught a rat by its nose in a trap and had to listen to it squealing and banging in the roof space. I had to head into the dark loft space with a torch and drop a brick on it. As the property was mid-terraced - the rats had a run of the walls and the eves of the roof space of all the houses in the row. None of the current methods of pest control seems humane - when caught by the trap it could take up to a minute to die.
Alun Jones, UK
We have been infested by rats over the last five years in our garden. each time the council have put "Poison Bran Bait" in the areas of garden where we had a rat run. We have this year removed and burnt all the decking, as the nests were growing. We were constantly finding the drowned bodies in the water feature, on our return from work. Apparently the poisoned rats run to the nearest water source, and then drown themselves. At last, five summers later, a newly-laid "gravel garden", all exits and entrances blocked, we are looking forward to a rat-free zone, for now.
Gill Smith, St Neots
I'm absolutely fed up with people who bang on about fortnightly bin collections causing problems. It really is simple, plastic can be recycled, glass can be recycled, cans & foil packaging, paper & card it can all be recycled. Anything left over? Oh yes, that old favourite, waste food. Well what about this, don't waste food. Plan out your menu, then buy what you need. Anything that does get left over can be incorporated into the next days meal (soups, stews, bubble & squeak).
Mark Revill, Sheffield, UK