The Guardian (London)

February 21, 1998 LENGTH: 5292 words

Planet Rat

BY: DAVID NEWNHAM

Rats are nasty, filthy vermin from a dark underworld, spreading disease wherever they go. Or so we are led to
believe. Yet throughout history, wherever man has gone, the rat has followed, our lives grudgingly synchronized.
Indeed, the rat has become a barometer of man's progress - a fact we'd do well to heed.



The creature is always as big as a cat. 'Guess what?' says the eye-witness. 'I just saw a gigantic rat.' It was in that
gloomy gap between platform and track, or crouching like a demon behind the wheely bin. It was lurking behind a
restaurant, where the food waste is stacked. Worse still, it was IN THE HOUSE! 'It just sat there, looking at me with
beady little eyes.' And it was large, you say? 'It was as big as a cat.' Had the thing been a fox, say - a fox or a hare, a
hedgehog or a badger - it would be a different story. The tone would be one of fascination, the undertone one of
respect. For the rat stands alone among our wild mammals. It is as popular as a slug in a salad bowl, as welcome as a
cockroach in a carrycot. Look up 'vermin' in the dictionary and what is the first example you see? Rat.

If, on the other hand, you look up 'rat' in the Encyclopaedia Britannica, a rather different image springs off the page. It
comes after the technical details ('there are 500 named forms of the genus Rattus, family Muridae, order Rodentia')
and after the bit about their having 'pointed noses and naked feet and tails'. Rats, says the fount of all facts (no prior
knowledge is taken for granted) 'are similar to, but generally larger than, mice'. Then comes the surprise: 'These are
aggressive, active, omnivorous, adaptable and fecund animals that live with man and have accompanied him almost
throughout the world.'

Almost? The sole exception is Antarctica - and even there, no one can swear that the odd family of fecund and
pointy-nosed omnivores has not taken up residence in the corner of a research station, having hitched a lift on some cosy supply ship. Because that's what they do - they stow away. And that's how we have unwittingly taken rats along with us on our world tour, introducing them first to Australia, and then to America, acting out our love-hate story on a global stage.

Ah no, you say. Love doesn't come into it - just hate. But how easy it would be for a Martian scientist to get a
contrary impression. Looking across at the next-door planet, would she not see two species locked in a close
embrace? Parasites, you say - mere parasites. Like the fleas they carry in their own fur, the rats cling to us for warmth
and food, bringing us, in return, nothing but disease. And that, I confess, is how I once saw the relationship, when first
I set out in search of the genus Rattus. But now I'm not at all sure.

It was the sewer stories that first caught my attention. Beneath our city streets, said all the newspapers one morning, the rodent population is exploding out of control. It seemed too bad to be true, like some Old Testament punishment for all that privatization and under-investment. The physical and political foundations of our public- health system are fast disintegrating, I quickly gathered. All over the country, water companies and local councils are squabbling over who should poison which rats, and when. There is no co-ordination any more. Meanwhile, the creatures, drawn by an accumulation of half-eaten fast-food, are burrowing up to street level, having gnawed through new-fangled plastic pipes or extruded their flexible bodies through improbably small gaps in our cracked and ruptured drains. Nearly a million homes in England alone suffer from rat infestation.

From time to time, a further detail would float to the surface of this unwholesome stew. 'Plague rats still alive,' said one headline. 'The black rat, infamous for spreading the devastating Great Plague and thought to have died out, is alive and well and living in east London, a TV documentary claims.' And, of course, there was Super Rat - 'big, smart and immune to poison'. Super Rat, said the papers, could soon become the norm. And then what would become of us?

In London, it was claimed for the umpteenth time, there is a rat within 20 yards of every man, woman and child.
Except that some sources reckoned it is 20 feet, and others omitted children from the count. On one point, though,
everyone was agreed: rats are on the increase. A female rat, you see, can begin breeding after just three months, and
thereafter can produce seven litters a year, with up to 22 young in each litter. Anyone with a grasp of compound
interest will be able to calculate that a single pair can produce a colony of 2,000 inside 12 months.

Keeping the lid on the rat population, therefore, is a task akin to painting the Forth Bridge. And as most public-health
experts now agree that we are painting less briskly than we were 40 years ago (despite the fact that water companies
devote more than pounds 2 million a year to rodent control), it comes as no surprise to learn that there are now more
rats in Britain than there were only a short while ago. The current estimate is 70 million, and rising. Which, as any
Martian scientist worth her salt could tell you, is greater than the number of people - including children. More rats than people? Perhaps it's time we were formally introduced.

Rodents, in one sense, are considerably bigger than cats. The order Rodentia (from the Latin verb rodere, 'to gnaw')
comprises 34 families, 354 genera and 1,685 known species. These figures are interesting if only because they add up to more genera and species than all the other mammals put together. Rodents can be arboreal (tree rats, squirrels),
aquatic (water rats, coypu), gliders (gliding squirrels), burrowers (mole rats), terrestrial . . . Of the 34 families of
rodent, the second largest, the Muridae, has 100 genera, totaling 460 species. One of those 100 genera is called
Rattus, and within that category are the two species - just two - that we commonly refer to as rats. Meet the black rat
and the Norway rat.

With chisel-like front teeth that grow continuously in order to cope with a diet of coarse vegetable matter (if a rat stops wearing down its front teeth, they grow so long that it dies), rats are veritable gnawing machines. They can even keep waste material out of their mouths while they bite through material such as wood, by using their split upper lips to form a seal behind their incisors. This gnawing ability, combined with legendary dexterity - the black rat can run up a stucco wall, and leap a five-foot gap - gains them access to the parts of our world that other mammals cannot reach. Small wonder that they are the most successful animals in history. Even a water-filled u-bend presents no obstacle . . .

Rats probably originated in southern Asia, migrating first to the Mediterranean and thence to Africa. The black rat was the first species to establish itself in Europe, hence the fearful symmetry of its Latin name, Rattus rattus. It is also called the roof rat, attic rat, house rat, Alexandrine rat, climbing rat and grey rat, the last being a more accurate assessment of its color. The black rat's head and body measure about 20cm, and the tail is even longer. Its climbing and jumping abilities are awesome.

The more adaptable Norway rat, Rattus norvegicus, is also called the brown rat, barn rat, sewer rat and wharf rat.
It has proportionately smaller ears and a more robust body than the black rat, and its head and body are larger - up to 25cm long. It tends to be brown, but can be grey, white, black or pied.

I could devote much effort to itemizing the differences between these two species. I could tell you (although you may
not wish to know), for example, that black rat droppings have pointed ends, while those of the Norway rat have
smooth, round ends.

I could explain how, when black and Nor-way rats live in the same building, the former live on the upper floors while
the latter occupy the lower (persons of nervous disposition ought not to dwell on this image). But I would be wasting
your time.

In Britain - throughout northern Europe, in fact - the only difference that matters is that one species has been successful where the other has more or less given up. Here, Norway rats are going from strength to strength. But, while black rats are plentiful in the US and Africa, in this country they are reduced to a handful of colonies (some of which do indeed live in east London).

So the 'plague rat' is virtually extinct in northern Europe? Well, yes, except that this plague-rat business is a little
misleading. True, it is the black rat whose fleas infected our forebears with bubonic plague. But that's only because
Norway rats, which are equally adept at harboring disease, did not arrive in Europe until the 18th century.

In 1727, vast hordes of them were seen by the naturalist Pallas swimming westwards across the Volga, and it was long believed that this visible migration marked their first arrival from central Asia. One thing is certain: once here, they
spread so rapidly that they became known as the Wanderratte, or migratory rat. And being more advanced and more
aggressive than black rats, they quickly became the dominant species. Today, the rat in your alley is almost certainly
Rattus norvegicus.

The same can be said for the rat on Carol Steele's shoulder. Galaxy Satin Cinnabar is the color of cinnamon, which is partly why he's called Cinnabar. And the other reason? 'Because I like the cinnabar moth,' says Carol. Which leaves Galaxy and Satin. 'Galaxy is the name of my rat stud,' says Carol. Rat what? 'I did say it was complicated.' We agree to skip the Satin, and move on to the delectable Mr. Chin. He is called Mr. Chin because he has a chinchilla coat - a soft fur of silvery grey. And then there are the others: Siamese, opal, buff - and too many to name individually.

Carol has three cats (she carefully avoids a war, though she reckons the rats wouldn't necessarily be on the losing side) and a number of rabbits, too. But it's clear that the rats rule her heart. Why? 'Because they're absolutely gorgeous (big sigh). They're intelligent and interested, and you can bring them out and tickle them, and they'll climb around and sit on your shoulder so you can walk around with them . . .' She's keen on them then? 'I'd never be without them.' And as it turns out, these little creatures changed her life.

It began 12 years ago, in an Essex lane. Carol was 18. But although she lived in the countryside, and although there
are more rats in Britain than there are people, she, like many of us, had never laid eyes on one. 'There was this poor,
sad, little thing at the side of the road, and I'm so soft I couldn't leave it there. Because I'd been brought up with this
belief that rats are huge, horrendous, terrifying things and mice are little, tiny things, it seemed like a mouse to me.

I think the mother had been killed, and this little one was not doing too well on its own. So I took it home and fed it,
and it curled up on my lap and was so lovely that I fell completely in love with it.' In fact, it was a wild rat. 'I didn't
know that, and when I found out, I had to let it go. But I missed it dreadfully. So a few months later, my mum bought
me one from the pet shop, and that was it.'

One rat led to another and, before long, Carol was breeding them and showing them at all the shows. Then, one day,
she got bored with winning cups and rosettes, and decided to take the hobby a step further. By this time, she was
working as an auxiliary nurse, but in her spare time she set herself the challenge of breeding a 'blue' rat. A rat with
bluish fur had been discovered in a pet shop, but other rat enthusiasts were finding it almost impossible to reproduce
the variety. Carol set to work learning about rat genetics, and before long had proved the doubters wrong. 'I felt sure it could be done, if it was tackled in the right way,' she says. 'So I spent four years just doing that. And now they're a
standardized variety.'

And Carol? Well, she's not an auxiliary nurse any more. 'Working with the rats, I discovered that I loved genetics so
much that I should really learn about it properly.' Today, she is a full-time student of cell and molecular biology at
Essex University, and all because of her rats. 'See?' she says. 'They really are amazing creatures.'

Her enthusiasm is far from unique. Fancy rats, all of them bred from Rattus norvegicus, are becoming increasingly
popular as pets. The National Rat Fancy Society has around 400 members, and the appeal is as multinational as the
rats themselves. A quick dip into the internet (just search for the word 'rat') instantly reveals the extent of the
phenomenon. 'My name is Rene van der Mark,' a typical entry begins. 'I am 37 years old and I live with my girlfriend,
Henny, in a small fishermen's village in Holland. One of our hobbies is keeping pet rats in our living room. On these
pages I will tell you all about it.'

Rene goes on to extol the virtues and attractions of his favored species, and is at pains to dispel all manner of myths
surrounding the genus Rattus. 'In the wild,' he says, 'rats do live on waste-dumps and among dirt. But consider this: It's our dirt and not theirs.' At home, he says, he has 'a small colony of rats'. And, to prove it, he peppers his thesis with family snapshots: 'Spot and Bianca', 'Rat sisters Patch and Happy', 'Spot, close-up', 'Mickey, standing at the door', say the captions. 'Scary and dangerous? People killed thousands of rats,' says Rene, 'and rats never killed people.'

It must have been happening for thousands of years. There's no way of knowing, or of counting up the victims. The
first written record comes from the time of the Byzantine emperor Justinian, so they call it the Plague Of Justinian. In
the city of Constantinople alone, 70,000 people died between AD542-543 - at one point, the inhabitants were dying
at a rate of 10,000 a week. Eventually, the disease burned itself out, following the trade routes to Italy and France,
continuing in fits and starts for the next half century and putting paid, some maintain, to Justinian's attempts to
re-establish the western Roman Empire.

The word 'plague' refers to any widespread disease that is very contagious and has a high fatality rate. But just as
'vermin' equates with rats, so 'plague' most often means bubonic plague, a disease that afflicts rats (among other
rodents) and that is transmitted by fleas. The chief villain here is a bacterium called Yersinia pestis, the word pestis
being Latin for 'plague', and Yersinia referring to Alexandre Yersin, who identified the organism in 1894. In parts of
Asia, Africa, and North and South America, rat populations act as reservoirs for Yersinia pestis. Most of the time,
only a small number of rodents actually become ill with the disease, but every so often they succumb in greater
numbers, leaving their fleas in need of alternative hosts on whom to feed. When this happens, the risk to other species, including humans, increases. So it was with the Plague Of Justinian.

Two to six days after being bitten by an infected flea, or sometimes after coming into contact with infected material, the human victim of bubonic plague begins to shiver and vomit, to suffer headaches, giddiness and intolerance to light, and finally to develop 'buboes' - hot and painful swellings of the lymph nodes in the groin, neck and armpits. After a while, blood vessels rupture beneath the skin, causing patches of tissue to die and turn black.

While today the disease is easily treated with antibiotics, if caught early enough, in 75 per cent of untreated cases it
proves fatal. Before antibiotics were developed, treatments included bathing in human urine, wearing excrement,
placing dead animals in victims' homes, applying leeches and drinking preparations of gold or ground emeralds. Such
were the precursors to a painful death - a death made all the more terrifying for those who witnessed it by the
gangrenous blackening of the victim's skin. In time, it came to be called the Black Death.

In the early 1330s, there was an outbreak of bubonic plague in China. The events that followed were to change the
course of history. From China, the disease was carried west, possibly by Tartars laying siege to the Crimean
cathedral town of Kaffa and by the residents of Kaffa who subsequently fled the siege. In October 1347, a number of
Italian merchant ships returning from the Black Sea docked in Sicily. Aboard the ships were people dying of bubonic
plague. By 1348, the disease had moved north, engulfing Italy and most of France and killing so swiftly that
Boccaccio in Florence wrote of people who 'ate lunch with their friends and dinner with their ancestors in paradise'.

At the height of the Vietnam war, Henry Kissinger vowed to bomb the enemy 'back into the Stone Age'. Kissinger's
phraseology conveys something of the impact of the Black Death on the medieval world. From the Mediterranean to
Russia, 25 million people - one third of the entire population - died, and a civilization that was blooming again after the centuries-long winter that followed the collapse of Rome was pushed right back to the brink of the abyss. Cultivated land returned to wilderness.

It was August 1348 when the pestilence turned up in the British Isles. In England alone, 1,000 villages were
permanently wiped out. Arguably, certain benefits flowed from all this suffering - a massive labor shortage tipped the
balance of power against the landowners, and everywhere people questioned feudal values and the authority of the
Church. But the downside went as deep as any downside can go. Jews were blamed, and massacred accordingly, and a general obsession with death tinged every aspect of life, so that even the art of the period became, once again,
cautious and stiff. The disease was to pick away at the carcass of society until the end of the century, dying down in
the winters as the fleas became dormant, but always returning with the warmer weather.

Then, in 1665, it came back properly. Infected rats were seen leaving ships docked at Weymouth in Dorset, and the
disease quickly spread to the capital. By the end of the year, the Great Plague of London had killed 17,440 people -
15 per cent of the population - before the Great Fire of London effectively sterilized the city.

Two hundred years later, in the 1860s, there was a third major outbreak. Again it started in the Far East, and again it
spread by ship. By the time it reached San Francisco, it had killed some 12,600,000 people. Yet it was the 1890s
before we began to work out what was going on.

First Yersin identified the bacillus. Then a Japanese scientist, Professor M Ogata, found the organism in the fleas of
infected rats. And, at last, the penny dropped. It was a short step to proving that fleas spread the disease from rats to
humans, and to developing a vaccine that would inoculate those most at risk of infection. Not that this was the end of
the matter. Far from it.

Los Angeles was to suffer an epidemic in 1924-1925, and in the 1960s Vietnam was reporting 10,000 deaths per
year, thanks, in all probability, to the destruction wrought by Dr Kissinger's bombs.

In recent years, outbreaks have occurred regularly in Africa, Asia and South America. In 1992, India was hit by a
pneumonic version of the plague, in the wake of the Maharashtra earthquake. Studies have suggested that the rat
population increased rapidly owing to the inadequacy of public-health services allied to the presence of uncollected
bodies.

The lessons, then, are clear: whenever things get messy - be it through war or some natural disaster - rats move in.
And when large numbers of rats come into contact with large numbers of people, disease crosses over into the human
population.

And rats have so much more to offer than bubonic plague. In America, some doctors believe that high rates of kidney
disease among the urban poor are linked to hantavirus, a serious, often deadly respiratory disease carried by the
rising rodent population and transferred to humans through rat saliva and droppings. One of the most dangerous
cross-over diseases, passed on by rat urine, is Weil's disease, which children can contract simply by swimming in
lakes and reservoirs - even splashing through puddles in high-risk areas. If the flu-like symptoms are not treated,
jaundice, kidney failure and death can follow.

Rats can also pass on tuberculosis, salmonella, listeria, Q fever and Lyme disease. Recent research on colonies of
rural rats suggests that they carry more disease- causing parasites than previously realized, and that many of the
diseases can be transmitted to people via their household pets. London Zoo was recently forced to call in outside
pest exterminators because of the danger of infection to some of their rarest species. Frank Wheeler, head keeper of
mammals, told television reporters that rats and mice 'carry a host of parasites and diseases that can wipe out an
animal in 48 hours'.

Long before they were implicated in the spread of specific diseases, rats had acquired the status of vermin, to be kept
down and kept out. Why? Because, given half a chance, rats eat everything in sight - crops, provisions, animal feed,
even poultry and young livestock. And the more food they can get their teeth into, the more they multiply, until they
themselves become a plague, like the Old Testament locusts that descended on Egypt.

'Rats!' wrote Robert Browning in his verse version of the 13th-century German folk tale, The Pied Piper Of Hamelin.

They fought the dogs and killed the cats, And bit the babies in the cradles, And ate the cheeses out of the vats, And
licked the soup from the cooks' own ladles, Split open the kegs of salted sprats, Made nests inside men's Sunday hats, And even spoiled the women's chats By drowning their speaking With shrieking and squeaking In fifty different sharps and flats.

The piper who led the rats away, but wasn't paid for his pains, returned to play a different tune on his flute. This time, it was the town's children who followed him, all except for a little lame boy. And every year, on June 26, Hamelin
commemorates the events with a procession of children dressed as rats.

Rats! Today, we offer them bait laced with 'rodenticides' - anticoagulants that prevent their blood from clotting so that
they hemorrhage and bleed to death (some 'super rats' have indeed become resistant to such drugs). We construct
elaborate traps (a rat caught in a spring trap may emit a loud, almost human scream) and lay glue boards in their path
(an animal stuck in glue may pull and pull until its leg or tail comes away from its body).

In the middle ages, the enemy was the black rat. Unlike Rattus norvegicus, the black rat's burrowing, low-living,
sewer-loving successor in Europe, Rattus rattus, is partial to houses and barns, to stables and outhouses. Once
established in a household, the black rat was virtually impossible to dislodge. In the absence of anticoagulants, sufferers were urged by the Church to seek assistance from St Gertrude of Nivelles. Today, in her native Belgium, the
7th-century virgin abbess is still invoked against rodent infestation, and water from her well and cakes baked in her
convent are believed to keep the creatures at bay.

In medieval England, dead cats had mouse corpses stuffed into their mouths before being buried in the foundations of houses. If this didn't keep rodents at bay (and obviously it didn't), traps and poisoned bait were used - cakes of
powdered aconite, or hellebore root mixed with honey and wheat flour. One writer advised householders, 'It is good
to cut up little pieces of sponge, and then if they swallow these and drink afterwards, they will swell up and die.' Don't
try this at home, children.

Europeans couldn't rid their towns of vermin, nor could they keep them off their ships when they decided not to be
Europeans any more. Rats went aboard with the provisions, and disembarked for a new life in the colonies.
Archaeologists examining the remains of a colonial Spanish ship off Emanuel Point, Florida, recently came upon the
bones of at least 21 black rats. The ship is believed to have been part of the 1559 expedition of Tristan de Luna,
which was the first attempt by Europeans to colonize Florida. The fleet was destroyed at anchor by a hurricane.

Rats have proved unusually adept at independent travel, moving between land masses on natural rafts of floating
vegetation (the process has the cute name 'waif dispersal'). But there's nothing like a good, well-provisioned ship.
Captain Cook introduced rats to Polynesia. He hadn't planned to, but when the exploding population of rodent
stowaways on board his ship became intolerable, he simply dropped anchor off an island near Tahiti and encouraged
the creatures to land by setting up plank walkways for them. Once ashore, rats invariably proved themselves ruthless
colonizers - almost as ruthless as their two-legged accomplices. Frequently, they destroyed native flora and fauna
before getting to work on the new crops. In Hawaii, they virtually wiped out indigenous species and wreaked havoc on the sugar plantations. So, in 1883, 72 mongooses were introduced. But this new species hunted by day, while the rats were nocturnal. The result? The mongooses ate all the native, ground-nesting birds and the rats carried on as before.

And, as if eating us out of house and homestead weren't enough, it turned out that the creatures had been infecting us
with deadly diseases all the while. Small wonder, then, that rats have pride of place in our nightmares - that when
Winston Smith, the hero of Orwell's 1984, finally encounters his greatest fear in Room 101, it turns out to be . . . but
you'll have read the book, of course. And you'll have read those celebrity questionnaires, too. Favourite smell?
'Fresh-mown grass.' Most hated person? 'Margaret Thatcher.' Worst fear? 'Rats!' The most successful mammal in
history is part of our shared mental landscape, like Hell and the Devil. It's even part of our language, although the line in the 1931 film Taxi was 'You dirty, yellow-bellied rat', not the stripped-down 'You dirty rat' so beloved of Cagney
impersonators.

From Werner Herzog's Nosferatu The Vampyre to Sondra Locke's Ratboy, the genus Rattus is a regular star of the
cinema screen. Remember Willard? 'Where your nightmares end,' went the line on the posters, 'Willard begins.' And
above the words, a toothy, pointed face stared out at the crowds and made them shudder in anticipation of all that
delicious revulsion.

It wasn't quite like that in 1990, though, when Hollywood ventured into the New York sewers to make a moralistic
martial-arts film for children. For the four reptilian heroes of Teenage Mutant Ninja Turtles deferred to a mammalian
mastermind - a wise old hero from the East in the form of a rat. Surprising? To Western eyes, perhaps. But in Chinese mythology, rats and mice are revered. As Rene van der Mark explains in his internet apologia for the species, 'Rats and mice are even believed to have occult knowledge. According to an old folk tale, rats can reach the very old age of 300 years. At the age of 100 years, the rat's fur turns white and the rat acquires the gift of prophesy.'

Hindus believe that Ganesh, the elephant-headed god of prosperity, is accompanied by a rat on his travels (even gods
aren't immune, it seems). Rat worship takes place at many sites in India, and some shrines are inhabited by tens of
thousands of rodents, which are fed and protected by dedicated priests. Hindus even feed rats in city parks, despite
the fact that they are reckoned to consume nearly a quarter of India's agricultural produce. This veneration of rats, and the fact that Hindus are supposed not to kill any creature, is thought to have contributed to the plague in Maharashtra.

The wise rat - the white rat that knows the future . . . is it such a foreign notion in the West? At first glance, yes. As I
sifted through the annals of rat/human relations, it seemed clear that our species is split into two irreconcilable camps,
East and West, with only a few rat fanciers on our side to moderate the universal loathing of the genus Rattus. And
then I saw the document. It was an American defence thing (they spelled it 'defense') and it had to do with research
into Gulf-war syndrome. 'Acute oral toxicity study of pyridostigmine bromide and DEET in the laboratory rat,' said the title.

They came thick and fast after that. 'New hope found for spine damage' detailed a series of experiments on lab rats
that will undoubtedly benefit paralysed humans. 'Hormone disruptors - how they work' explained what our neurologists can deduce by feeding rats with salmon from a polluted lake. In Cambridgeshire, somebody had spent 59 months cloning rat genes to further our knowledge of organ transplantation. And a Dr Joseph LeDoux was tracing the routes of fear - our fear - by threatening lab rats with electric shocks (they emit high-frequency screams to warn their fellows), then using chemical stains to track the flow of terror through their little brains.

The list of experiments was endless. And while nobody seemed to be claiming that the lab rat - an albino strain of our
friend Rattus norvegicus - had a great deal of wisdom in its pointed head (and it's certainly no prophet), it was clear
that the creature had important things to tell us. In short, when we want to know something about ourselves, we often
turn to rats for the answer.

One scientist I spoke to summed up the advantages of the species. 'They are big enough to do physiological studies
on, but they are small enough to be cheap to keep,' she said. She described a standard experiment, involving platforms submerged in opaque, milky liquid. How quickly does a rat learn to find the platform? How well does it remember the lesson? And how does its performance alter when parts of its brain are interfered with? It's our own brains that are being investigated, of course, but only the likes of Dr Mengele experiment with live human beings. 'Rats are big enough that you can find an area of the brain and insert an electrode into it, then measure the brain's response to drugs or trauma,' said the scientist. 'Also, they're calm, reasonably intelligent and nice to handle.' Nice to handle? 'They don't savage people.'

But then, they wouldn't really - at least not on purpose. They might have wiped out a third of Europe, but that wasn't
intentional. They might eat a farmer out of a year's food - even gnaw their way through his paper money - but only
because they are hungry. As for 'going for the throat like a cornered rat' . . . well, it's just not their style. 'They'll maybe give you a nip if you trap their tail in the door,' said Carol Steele. 'But a cat will do that.'

The fact is, the rat doesn't mean us any harm. Then again, neither did smallpox. We even depend on the creature to
some extent, as a pet, as a subject of our laboratory experiments - even, perhaps, as an embodiment of our fears. In
an ideal world, rats and people would live happily side by side. Even smallpox could join in the fun, so long as he
agreed to behave.

But, in reality, rats are so successful and so adaptable that we have no choice but to keep the lid on them. Their place
must be in the sewer, out of sight and out of mind. Don't worry. It's nice and cosy down there. They probably like it.
And when, from time to time, they do emerge, busting in droves out of broken drains and milling, big as cats, around
discarded burgers, they might even be doing us a service - acting as a kind of barometer, if you like. For the visible rat - the rat on the surface - is telling us something about ourselves. 'All is not well,' he says. And we would do well to
listen.